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Seismic Collapse Safety of Reinforced ConcreteBuildings.II:Comparative Assessment of Nonductile and Ductile Moment FramesAbbie B.Liel,M.ASCE 1;Curt B.Haselton,M.ASCE 2;and Gregory G.Deierlein,F.ASCE 3Abstract:This study is the second of two companion papers to examine the seismic collapse safety of reinforced concrete frame buildings,and examines nonductile moment frames that are representative of those built before the mid-1970s in California.The probabilistic assessment relies on nonlinear dynamic simulation of structural response to calculate the collapse risk,accounting for uncertainties in ground-motion characteristics and structural modeling.The evaluation considers a set of archetypical nonductile RC frame structures of varying height that are designed according to the seismic provisions of the 1967Uniform Building Code.The results indicate that nonductile RC frame structures have a mean annual frequency of collapse ranging from 5to 14×10À3at a typical high-seismic California site,which is approximately 40times higher than corresponding results for modern code-conforming special RC moment frames.These metrics demonstrate the effectiveness of ductile detailing and capacity design requirements,which have been introduced over the past 30years to improve the safety of RC buildings.Data on comparative safety between nonductile and ductile frames may also inform the development of policies for appraising and mitigating seismic collapse risk of existing RC frame buildings.DOI:10.1061/(ASCE)ST.1943-541X .0000275.©2011American Society of Civil Engineers.CE Database subject headings:Structural failures;Earthquake engineering;Structural reliability;Reinforced concrete;Concrete structures;Seismic effects;Frames.Author keywords:Collapse;Earthquake engineering;Structural reliability;Reinforced concrete structures;Buildings;Commercial;Seismic effects.IntroductionReinforced concrete (RC)frame structures constructed in Califor-nia before the mid-1970s lack important features of good seismic design,such as strong columns and ductile detailing of reinforce-ment,making them potentially vulnerable to earthquake-induced collapse.These nonductile RC frame structures have incurred significant earthquake damage in the 1971San Fernando,1979Imperial Valley,1987Whittier Narrows,and 1994Northridge earthquakes in California,and many other earthquakes worldwide.These factors raise concerns that some of California ’s approxi-mately 40,000nonductile RC structures may present a significant hazard to life and safety in future earthquakes.However,data are lacking to gauge the significance of this risk,in relation to either the building population at large or to specific buildings.The collapse risk of an individual building depends not only on the building code provisions employed in its original design,but also structuralconfiguration,construction quality,building location,and site-spe-cific seismic hazard information.Apart from the challenges of ac-curately evaluating the collapse risk is the question of risk tolerance and the minimum level of safety that is appropriate for buildings.In this regard,comparative assessment of buildings designed accord-ing to old versus modern building codes provides a means of evalu-ating the level of acceptable risk implied by current design practice.Building code requirements for seismic design and detailing of reinforced concrete have changed significantly since the mid-1970s,in response to observed earthquake damage and an in-creased understanding of the importance of ductile detailing of reinforcement.In contrast to older nonductile RC frames,modern code-conforming special moment frames for high-seismic regions employ a variety of capacity design provisions that prevent or delay unfavorable failure modes such as column shear failure,beam-column joint failure,and soft-story mechanisms.Although there is general agreement that these changes to building code require-ments are appropriate,there is little data to quantify the associated improvements in seismic safety.Performance-based earthquake engineering methods are applied in this study to assess the likelihood of earthquake-induced collapse in archetypical nonductile RC frame structures.Performance-based earthquake engineering provides a probabilistic framework for re-lating ground-motion intensity to structural response and building performance through nonlinear time-history simulation (Deierlein 2004).The evaluation of nonductile RC frame structures is based on a set of archetypical structures designed according to the pro-visions of the 1967Uniform Building Code (UBC)(ICBO 1967).These archetype structures are representative of regular well-designed RC frame structures constructed in California between approximately 1950and 1975.Collapse is predicted through1Assistant Professor,Dept.of Civil,Environmental and Architectural Engineering,Univ.of Colorado,Boulder,CO 80309.E-mail:abbie .liel@ 2Assistant Professor,Dept.of Civil Engineering,California State Univ.,Chico,CA 95929(corresponding author).E-mail:chaselton@csuchico .edu 3Professor,Dept.of Civil and Environmental Engineering,Stanford Univ.,Stanford,CA 94305.Note.This manuscript was submitted on July 14,2009;approved on June 30,2010;published online on July 15,2010.Discussion period open until September 1,2011;separate discussions must be submitted for individual papers.This paper is part of the Journal of Structural Engineer-ing ,V ol.137,No.4,April 1,2011.©ASCE,ISSN 0733-9445/2011/4-492–502/$25.00.492/JOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .nonlinear dynamic analysis of the archetype nonductile RC frames,using simulation models capable of capturing the critical aspects of strength and stiffness deterioration as the structure collapses.The outcome of the collapse performance assessment is a set of measures of building safety and relating seismic collapse resistance to seismic hazard.These results are compared with the metrics for ductile RC frames reported in a companion paper (Haselton et al.2011b ).Archetypical Reinforced Concrete Frame StructuresThe archetype nonductile RC frame structures represent the expected range in design and performance in California ’s older RC frame buildings,considering variations in structural height,configuration and design details.The archetype configurations explore key design parameters for RC components and frames,which were identified through previous analytical and experimental studies reviewed by Haselton et al.(2008).The complete set of archetype nonductile RC frame buildings developed for this study includes 26designs (Liel and Deierlein 2008).This paper focuses primarily on 12of these designs,varying in height from two to 12stories,and including both perimeter (P )and space (S )frame lateral resisting systems with alternative design details.All archetype buildings are designed for office occupancies with an 8-in.(20-cm)flat-slab floor system and 25-ft (7.6-m)column spacing.The 2-and 4-story buildings have a footprint of 125ft by 175ft (38.1m by 53.3m),and the 8-and 12-story buildings measure 125ft (38.1m)square in plan.Story heights are 15ft (4.6m)in the first story and 13ft (4.0m)in all other stories.Origi-nal structural drawings for RC frame buildings constructed in California in the 1960s were used to establish typical structural configurations and geometry for archetype structures (Liel and Deierlein 2008).The archetypes are limited to RC moment frames without infill walls,and are regular in elevation and plan,without major strength or stiffness irregularities.The nonductile RC archetype structures are designed for the highest seismic zone in the 1967UBC,Zone 3,which at that time included most of California.Structural designs of two-dimensional frames are governed by the required strength and stiffness to satisfy gravity and seismic loading combinations.The designs also satisfy all relevant building code requirements,including maximum and minimum reinforcement ratios and maximum stirrup spacing.The 1967UBC permitted an optional reduction in the design base shear if ductile detailing requirements were employed,however,this reduction is not applied and only standard levels of detailing are considered in this study.Design details for each structure areTable 1.Design Characteristics of Archetype Nonductile and Ductile RC Frames Stucture Design base shear coefficient a,bColumn size c (in :×in.)Column reinforcementratio,ρColumn hoop spacing d,e (in.)Beam size f (in :×in.)Beam reinforcementratios ρ(ρ0)Beam hoop spacing (in.)Nonductile2S 0.08624×240.0101224×240.006(0.011)112P 0.08630×300.0151530×300.003(0.011)114S 0.06820×200.0281020×260.007(0.014)124P 0.06824×280.0331424×320.007(0.009)158S 0.05428×280.0141424×260.006(0.013)118P 0.05430×360.0331526×360.008(0.010)1712S 0.04732×320.025926×300.006(0.011)1712P 0.04732×400.032930×380.006(0.013)184S g 0.06820×200.028 6.720×260.007(0.014)84S h 0.06820×200.0281020×260.007(0.014)1212S g 0.04732×320.025626×300.006(0.011)1112S h 0.04732×320.025926×300.006(0.011)17Ductile2S 0.12522×220.017518×220.006(0.012) 3.52P 0.12528×300.018528×280.007(0.008)54S 0.09222×220.016522×240.004(0.008)54P 0.09232×380.016 3.524×320.011(0.012)58S 0.05022×220.011422×220.006(0.011) 4.58P 0.05026×340.018 3.526×300.007(0.008)512S 0.04422×220.016522×280.005(0.008)512P0.04428×320.0223.528×380.006(0.007)6aThe design base shear coefficient in the 1967UBC is given by C ¼0:05=T ð1=3Þ≤0:10.For moment resisting frames,T ¼0:1N ,where N is the number of stories (ICBO 1967).bThe design base shear coefficient for modern buildings depends on the response spectrum at the site of interest.The Los Angeles site has a design spectrumdefined by S DS ¼1:0g and S D1¼0:60g.The period used in calculation of the design base shear is derived from the code equation T ¼0:016h 0:9n ,where h n isthe height of the structure in feet,and uses the coefficient for upper limit of calculated period (C u ¼1:4)(ASCE 2002).cColumn properties vary over the height of the structure and are reported here for an interior first-story column.dConfiguration of transverse reinforcement in each member depends on the required shear strength.There are at least two No.3bars at every location.eConfiguration of transverse reinforcement in ductile RC frames depends on the required shear strength.All hooks have seismic detailing and use No.4bars (ACI 2005).fBeam properties vary over the height of the structure and are reported here are for a second-floor beam.gThese design variants have better-than-average beam and column detailing.hThese design variants have better-than-average joint detailing.JOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011/493D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .summarized in Table 1,and complete documentation of the non-ductile RC archetypes is available in Liel and Deierlein (2008).Four of the 4-and 12-story designs have enhanced detailing,as described subsequently.The collapse performance of archetypical nonductile RC frame structures is compared to the set of ductile RC frame archetypes presented in the companion paper (Haselton et al.2011b ).As sum-marized in Table 2,these ductile frames are designed according to the provisions of the International Building Code (ICC 2003),ASCE 7(ASCE 2002),and ACI 318(ACI 2005);and meet all gov-erning code requirements for strength,stiffness,capacity design,and detailing for special moment frames.The structures benefit from the provisions that have been incorporated into seismic design codes for reinforced concrete since the 1970s,including an assort-ment of capacity design provisions [e.g.,strong column-weak beam (SCWB)ratios,beam-column and joint shear capacity design]and detailing improvements (e.g.,transverse confinement in beam-column hinge regions,increased lap splice requirements,closed hooks).The ductile RC frames are designed for a typical high-seismic Los Angeles site with soil class S d that is located in the transition region of the 2003IBC design maps (Haselton and Deierlein 2007).A comparison of the structures described in Table 1reflects four decades of changes to seismic design provisions for RC moment frames.Despite modifications to the period-based equation for design base shear,the resulting base shear coefficient is relatively similar for nonductile and ductile RC frames of the same height,except in the shortest structures.More significant differencesbetween the two sets of buildings are apparent in member design and detailing,especially in the quantity,distribution,and detailing of transverse reinforcement.Modern RC frames are subject to shear capacity design provisions and more stringent limitations on stirrup spacing,such that transverse reinforcement is spaced two to four times more closely in ductile RC beams and columns.The SCWB ratio enforces minimum column strengths to delay the formation of story mechanisms.As a result,the ratio of column to beam strength at each joint is approximately 30%higher (on average)in the duc-tile RC frames than the nonductile RC frames.Nonductile RC frames also have no special provision for design or reinforcement of the beam-column joint region,whereas columns in ductile RC frames are sized to meet joint shear demands with transverse reinforcement in the joints.Joint shear strength requirements in special moment frames tend to increase the column size,thereby reducing axial load ratios in columns.Nonlinear Simulation ModelsNonlinear analysis models for each archetype nonductile RC frame consist of a two-dimensional three-bay representation of the lateral resisting system,as shown in Fig.1.The analytical model repre-sents material nonlinearities in beams,columns,beam-column joints,and large deformation (P -Δ)effects that are important for simulating collapse of frames.Beam and column ends and the beam-column joint regions are modeled with member end hinges that are kinematically constrained to represent finite joint sizeTable 2.Representative Modeling Parameters in Archetype Nonductile and Ductile RC Frame Structures Structure Axial load a,b (P =A g f 0c )Initial stiffness c Plastic rotation capacity (θcap ;pl ,rad)Postcapping rotation capacity (θpc ,rad)Cyclicdeterioration d (λ)First mode period e (T 1,s)Nonductile2S 0.110:35EI g 0.0180.04041 1.12P 0.030:35EI g 0.0170.05157 1.04S 0.300:57EI g 0.0210.03333 2.04P 0.090:35EI g 0.0310.10043 2.08S 0.310:53EI g 0.0130.02832 2.28P 0.110:35EI g 0.0250.10051 2.412S 0.350:54EI g 0.0290.06353 2.312P 0.140:35EI g 0.0450.10082 2.84S f 0.300:57EI g 0.0320.04748 2.04S g 0.300:57EI g 0.0210.03333 2.012S f 0.350:54EI g 0.0430.09467 2.312S g 0.350:54EI g 0.0290.06353 2.3Ductile2S 0.060:35EI g 0.0650.100870.632P 0.010:35EI g 0.0750.1001110.664S 0.130:38EI g 0.0570.100800.944P 0.020:35EI g 0.0860.100133 1.18S 0.210:51EI g 0.0510.10080 1.88P 0.060:35EI g 0.0870.100122 1.712S 0.380:68EI g 0.0360.05857 2.112P0.070:35EI g0.0700.1001182.1a Properties reported for representative interior column in the first story.(Column model properties data from Haselton et al.2008.)bExpected axial loads include the unfactored dead load and 25%of the design live load.cEffective secant stiffness through 40%of yield strength.dλis defined such that the hysteretic energy dissipation capacity is given by Et ¼λM y θy (Haselton et al.2008).eObtained from eigenvalue analysis of frame model.fThese design variants have better-than-average beam and column detailing.gThese design variants have better-than-average joint detailing.494/JOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .effects and connected to a joint shear spring (Lowes and Altoontash 2003).The structural models do not include any contribution from nonstructural components or from gravity-load resisting structural elements that are not part of the lateral resisting system.The model is implemented in OpenSees with robust convergence algorithms (OpenSees 2009).As in the companion paper,inelastic beams,columns,and joints are modeled with concentrated springs idealized by a trilinear back-bone curve and associated hysteretic rules developed by Ibarra et al.(2005).Properties of the nonlinear springs representing beam and column elements are predicted from a series of empirical relation-ships relating column design characteristics to modeling parame-ters and calibrated to experimental data for RC columns (Haselton et al.2008).Tests used to develop empirical relationships include a large number of RC columns with nonductile detailing,and predicted model parameters reflect the observed differences in moment-rotation behavior between nonductile and ductile RC elements.As in the companion paper,calibration of model param-eters for RC beams is established on columns tested with low axial load levels because of the sparse available beam data.Fig.2(a)shows column monotonic backbone curve properties for a ductile and nonductile column (each from a 4-story building).The plastic rotation capacity θcap ;pl ,which is known to have an important influence on collapse prediction,is a function of the amount of column confinement reinforcement and axial load levels,and is approximately 2.7times greater for the ductile RC column.The ductile RC column also has a larger postcapping rotation capacity (θpc )that affects the rate of postpeak strength degradation.Fig.2(b)illustrates cyclic deterioration of column strength and stiffness under a typical loading protocol.Cyclic degradation of the initial backbone curve is controlled by the deterioration parameter λ,which is a measure of the energy dissipation capacity and is smaller in nonductile columns because of poor confinement and higher axial loads.Model parameters are calibrated to the expected level of axial compression in columns because of gravity loads and do not account for axial-flexure-shear interaction during the analysis,which may be significant in taller buildings.Modeling parameters for typical RC columns in nonductile and ductile archetypes are summarized in Table 2.Properties for RC beams are similar and reported elsewhere (Liel and Deierlein 2008;Haselton and Deierlein 2007).All element model properties are calibrated to median values of test data.Although the hysteretic beam and column spring parameters incorporate bond-slip at the member ends,they do not account for significant degradations that may occur because of anchorage or splice failure in nonductile frames.Unlike ductile RC frames,in which capacity design require-ments limit joint shear deformations,nonductile RC frames may experience significant joint shear damage contributing to collapse (Liel and Deierlein 2008).Joint shear behavior is modeled with an inelastic spring,as illustrated in Fig.1and defined by a monotonic backbone and hysteretic rules (similar to those shown in Fig.2for columns).The properties of the joint shear spring are on the basisofFig.1.Schematic of the RC frame structural analysismodel(a)(b)Fig.2.Properties of inelastic springs used to model ductile and non-ductile RC columns in the first story of a typical 4-story space frame:(a)monotonic behavior;(b)cyclic behaviorJOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011/495D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .selected subassembly data of joints with minimal amounts of trans-verse reinforcement and other nonductile characteristics.Unfortu-nately,available data on nonconforming joints are limited.Joint shear strength is computed using a modified version of the ACI 318equation (ACI 2005),and depends on joint size (b j is joint width,h is height),concrete compressive strength (f 0c ,units:psi),and confinement (γ,which is 12to 20depending on the configu-ration of confining beams)such that V ¼0:7γffiffiffiffif 0c p b j h .The 0.7modification factor is on the basis of empirical data from Mitra and Lowes (2007)and reflects differences in shear strength between seismically detailed joints (as assumed in ACI 318Chap.21)and joints without transverse reinforcement,of the type consid-ered in this study.Unlike conforming RC joints,which are assumed to behave linear elastically,nonductile RC joints have limited duc-tility,and shear plastic deformation capacity is assumed to be 0.015and 0.010rad for interior and exterior joints,respectively (Moehle et al.2006).For joints with axial load levels below 0.095,data from Pantelides et al.(2002)are used as the basis for a linear increase in deformation capacity (to a maximum of 0.025at zero axial load).Limited available data suggest a negative postcapping slope of approximately 10%of the effective initial stiffness is appropriate.Because of insubstantial data,cyclic deterioration properties are assumed to be the same as that for RC beams and columns.The calculated elastic fundamental periods of the RC frame models,reported in Table 2,reflect the effective “cracked ”stiffness of the beams and columns (35%of EI g for RC beams;35%to 80%of EI g for columns),finite joint sizes,and panel zone flexibility.The effective member stiffness properties are determined on the basis of deformations at 40%of the yield strength and include bond-slip at the member ends.The computed periods are signifi-cantly larger than values calculated from simplified formulas in ASCE (2002)and other standards,owing to the structural modeling assumptions (specifically,the assumed effective stiffness and the exclusion of the gravity-resisting system from the analysis model)and intentional conservatism in code-based formulas for building period.Nonlinear static (pushover)analysis of archetype analysis mod-els shows that the modern RC frames are stronger and have greater deformation capacities than their nonductile counterparts,as illus-trated in Fig.3.The ASCE 7-05equivalent seismic load distribu-tion is applied in the teral strength is compared on the basis of overstrength ratio,Ω,defined as the ratio between the ultimate strength and the design base shear.The ductility is com-pared on the basis of ultimate roof drift ratio (RDR ult ),defined as the roof drift ratio at which 20%of the lateral strength of the structure has been lost.As summarized in Table 3,for the archetype designs in this study,the ductile RC frames have approximately 40%more overstrength and ultimate roof drift ratios three times larger than the nonductile RC frames.The larger structural deformation capacity and overstrength in the ductile frames results from (1)greater deformation capacity in ductile versus nonductile RC components (e.g.,compare column θcap ;pl and θpc in Table 2),(2)the SCWB requirements that promote more distributed yielding over multiple stories in the ductile frames,(3)the larger column strengths in ductile frames that result from the SCWB and joint shear strength requirements,and (4)the required ratios of positive and negative bending strength of the beams in the ductile frames.Fig.3(b)illustrates the damage concentration in lower stories,especially in the nonductile archetype structures.Whereas nonlin-ear static methods are not integral to the dynamic collapse analyses,the pushover results help to relate the dynamic collapse analysis results,described subsequently,and codified nonlinear static assessment procedures.Collapse Performance Assessment ProcedureSeismic collapse performance assessment for archetype nonductile RC frame structures follows the same procedure as in the companion study of ductile RC frames (Haselton et al.2011b ).The collapse assessment is organized using incremental dynamic analysis (IDA)of nonlinear simulation models,where each RC frame model is subjected to analysis under multiple ground motions that are scaled to increasing amplitudes.For each ground motion,collapse is defined on the basis of the intensity (spectral acceleration at the first-mode period of the analysis model)of the input ground motion that results in structural collapse,as iden-tified in the analysis by excessive interstory drifts.The IDA is repeated for each record in a suite of 80ground motions,whose properties along with selection and scaling procedures are de-scribed by Haselton et al.(2011b ).The outcome of this assessment is a lognormal distribution (median,standard deviation)relating that structure ’s probability of collapse to the ground-motion inten-sity,representing a structural collapse fragility function.Uncer-tainty in prediction of the intensity at which collapse occurs,termed “record-to-record ”uncertainty (σln ;RTR ),is associated with variation in frequency content and other characteristics of ground-motion records.Although the nonlinear analysis model for RC frames can simulate sidesway collapse associated with strength and stiffness degradation in the flexural hinges of the beams andcolumnsFig.3.Pushover analysis of ductile and nonductile archetype 12-story RC perimeter frames:(a)force-displacement response;and (b)distri-bution of interstory drifts at the end of the analysis496/JOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .and beam-column joint shear deformations,the analysis model does not directly capture column shear failure.The columns in the archetype buildings in this study are expected to yield first in flexure,followed by shear failure (Elwood and Moehle 2005)rather than direct shear failure,as may be experienced by short,squat nonductile RC columns.However,observed earthquake damage and laboratory studies have shown that shear failure and subsequent loss of gravity-load-bearing capacity in one column could lead to progressive collapse in nonductile RC frames.Column shear failure is not incorporated directly because of the difficulties in accurately simulating shear or flexure-shear failure and subsequent loss of axial load-carrying capacity (Elwood 2004).Collapse modes related to column shear failure are therefore detected by postprocessing dynamic analysis results using compo-nent limit state ponent limit state functions are devel-oped from experimental data on nonductile beam-columns and predict the median column drift ratio (CDR)at which shear failure,and the subsequent loss of vertical-load-carrying capacity,will occur.Here,CDR is defined similarly to interstory drift ratio,but excludes the contribution of beam rotation and joint deforma-tion to the total drift because the functions are established on data from column component tests.Component fragility relationships for columns failing in flexure-shear developed by Aslani and Miranda (2005),building on work by Elwood (2004),are employed in this study.For columns with nonductile shear design and detailing in this study and axial load ratios of P =A g f 0c between 0.03and 0.35,Aslani and Miranda (2005)predict that shear failure occurs at a median CDR between 0.017and 0.032rad,depending on the properties of the column,and the deformation capacity decreases with increasing axial load.Sub-sequent loss of vertical-carrying capacity in a column is predicted to occur at a median CDR between 0.032and 0.10rad,again depending on the properties of the column.Since the loss of vertical-load-carrying capacity of a column may precipitate progressive structure collapse,this damage state is defined as collapse in this assessment.In postprocessing dynamic analysis results,the vertical collapse limit state is reached if,during the analysis,the drift in any column exceeds the median value of that column ’s component fragility function.If the vertical collapse mode is predicted to occur at a smaller ground-motion intensity than the sidesway collapse mode (for a particular record),then the collapse statistics are updated.This simplified approach can be shown to give comparable median results to convolving the probability distribution of column drifts experienced as a function of ground-motion intensity (engineering demands)with the com-ponent fragility curve (capacity).The total uncertainty in the col-lapse fragility is assumed to be similar in the sidesway-only case and the sidesway/axial collapse case,as it is driven by modeling and record-to-record uncertainties rather than uncertainty in the component fragilities.Incorporating this vertical collapse limit state has the effect of reducing the predicted collapse capacity of the structure.Fig.4illustrates the collapse fragility curves for the 8-story RC space frame,with and without consideration of shear failure and axial failure following shear.As shown,if one considers collapse to occur with column shear failure,then the collapse fragility can reduce considerably compared to the sidesway collapse mode.However,if one assumes that shear failure of one column does not constitute collapse and that collapse is instead associated with the loss in column axial capacity,then the resulting collapse capac-ity is only slightly less than calculations for sidesway alone.For the nonductile RC frame structures considered in this study,the limit state check for loss of vertical-carrying capacity reduces the median collapse capacity by 2%to 30%as compared to the sidesway collapse statistics that are computed without this check (Liel and Deierlein 2008).Table 3.Results of Collapse Performance Assessment for Archetype Nonductile and Ductile RC Frame Structures Structure ΩRDR ult Median Sa ðT 1Þ(g)Sa 2=50ðT 1Þ(g)Collapse marginλcollapse ×10À4IDR collapse RDR collapseNonductile 2S 1.90.0190.470.800.591090.0310.0172P 1.60.0350.680.790.85470.0400.0284S 1.40.0160.270.490.541070.0540.0284P 1.10.0130.310.470.661000.0370.0178S 1.60.0110.290.420.68640.0420.0118P 1.10.0070.230.310.751350.0340.00912S 1.90.0100.290.350.83500.0340.00612P 1.10.0050.240.420.561190.0310.0064S a 1.40.0160.350.490.72380.0560.0244S b 1.60.0180.290.490.60890.0610.02612S a 1.90.0120.330.350.93350.0390.00912S b 2.20.0120.460.351.32160.0560.012Ductile 2S 3.50.085 3.55 1.16 3.07 1.00.0970.0752P 1.80.0672.48 1.13 2.193.40.0750.0614S 2.70.047 2.220.87 2.56 1.70.0780.0504P 1.60.038 1.560.77 2.04 3.60.0850.0478S 2.30.028 1.230.54 2.29 2.40.0770.0338P 1.60.023 1.000.57 1.77 6.30.0680.02712S 2.10.0220.830.44 1.914.70.0550.01812P1.70.0260.850.471.845.20.0530.016a These design variants have better-than-average beam and column detailing.bThese design variants have better-than-average joint detailing.JOURNAL OF STRUCTURAL ENGINEERING ©ASCE /APRIL 2011/497D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S u l t a n Q a b o o s U n i v e r s i t y o n 06/21/14. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .。

Spring相关的外文文献和翻译(毕设论文必备)

Spring相关的外文文献和翻译(毕设论文必备)

附录1 外文原文Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory”lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole world view on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution forall middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container. It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that canbe used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classes for O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlyingO/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remoteservices without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is included for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entire configuration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (andrelevant even in a book on “J2EE without EJB”) because the use of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice. Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transaction coordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is alsopopular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in theWEB-INF directory, containing bean defini-tions according to the “spring-beans”DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource”bean, a “myInventoryManager”bean, and a “myProductManager”bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource”class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager”class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager”class=”ebusiness.DefaultProductManager”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton”scope: one instance per context. The “myInventoryManager”bean will automatically be wired up with the defined DataSource, while “myProductManager”will in turn receive a reference to the “myInventoryManager”bean. Those objects (traditionally called “beans”in Spring terminology) need to expose only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener </listener-class></listener>...</web-app>After initialization of the web app, the root web application context will beavailable as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web.context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasiveapplication framework.Fundamental InterfacesThe fundamental lightweight container interface isorg.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not found in the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be usedstan-dalone if no other Spring services are required.附录2 中文译文Spring框架介绍Spring框架:这是一个流行的开源应用框架,它可以解决很多问题。

钢结构毕业设计论文(中英)

钢结构毕业设计论文(中英)

浅谈钢结构现在,钢以一种或者形式逐渐成为全球应用最广泛的建筑材料。

对于建筑构架,除了很特殊的工程之外,钢材几乎已经完全取代了木材,总的来说,对于桥梁和结构骨架,钢也逐渐代替了铸铁和炼铁。

最为现代最重要的建筑材料,钢是在19世纪被引入到建筑中的,钢实质上是铁和少量碳的合金,一直要通过费力的过程被制造,所以那时的钢仅仅被用在一些特殊用途,例如制造剑刃。

1856年贝塞麦炼钢发发明以来,刚才能以低价大量获得。

刚最显著的特点就是它的抗拉强度,也就是说,当作用在刚上的荷载小于其抗拉强度荷载时,刚不会失去它的强度,正如我们所看到的,而该荷载足以将其他材料都拉断。

新的合金又进一步加强了钢的强度,与此同时,也消除了一些它的缺陷,比如疲劳破坏。

钢作为建筑材料有很多优点。

在结构中使用的钢材成为低碳钢。

与铸铁相比,它更有弹性。

除非达到弹性极限,一旦巴赫在曲调,它就会恢复原状。

即使荷载超出弹性和在很多,低碳钢也只是屈服,而不会直接断裂。

然而铸铁虽然强度较高,却非常脆,如果超负荷,就会没有征兆的突然断裂。

钢在拉力(拉伸)和压力作用下同样具有高强度这是钢优于以前其他结构金属以及砌砖工程、砖石结构、混凝土或木材等建筑材料的优点,这些材料虽然抗压,但却不抗拉。

因此,钢筋被用于制造钢筋混凝土——混凝土抵抗压力,钢筋抵抗拉力。

在钢筋框架建筑中,用来支撑楼板和墙的水平梁也是靠竖向钢柱支撑,通常叫做支柱,除了最底层的楼板是靠地基支撑以外,整个结构的负荷都是通过支柱传送到地基上。

平屋面的构造方式和楼板相同,而坡屋顶是靠中空的钢制个构架,又成为三角形桁架,或者钢制斜掾支撑。

一座建筑物的钢构架设计是从屋顶向下进行的。

所有的荷载,不管是恒荷载还是活荷载(包括风荷载),都要按照连续水平面进行计算,直到每一根柱的荷载确定下来,并相应的对基础进行设计。

利用这些信息,结构设计师算出整个结构需要的钢构件的规格、形状,以及连接细节。

对于屋顶桁架和格构梁,设计师利用“三角剖分”的方法,因为三角形是唯一的固有刚度的结构。

本科毕业设计外文文献翻译

本科毕业设计外文文献翻译

(Shear wall st ructural design ofh igh-lev el fr ameworkWu Jiche ngAbstract : In t his pape r the basic c oncepts of man pow er from th e fra me sh ear w all str uc ture, analy sis of the struct ur al des ign of th e c ont ent of t he fr ame she ar wall, in cludi ng the seism ic wa ll she ar spa本科毕业设计外文文献翻译学校代码: 10128学 号:题 目:Shear wall structural design of high-level framework 学生姓名: 学 院:土木工程学院 系 别:建筑工程系 专 业:土木工程专业(建筑工程方向) 班 级:土木08-(5)班 指导教师: (副教授)nratiodesign, and a concretestructure in themost co mmonly usedframe shear wallstructurethedesign of p oints to note.Keywords: concrete; frameshearwall structure;high-risebuildingsThe wall is amodern high-rise buildings is an impo rtant buildingcontent, the size of theframe shear wall must comply with building regulations. The principle is that the largersizebut the thicknessmust besmaller geometric featuresshouldbe presented to the plate,the force is close to cylindrical.The wall shear wa ll structure is a flatcomponent. Itsexposure to the force along the plane level of therole ofshear and moment, must also take intoaccountthe vertical pressure.Operate under thecombined action ofbending moments and axial force andshear forcebythe cantilever deep beam under the action of the force levelto loo kinto the bottom mounted on the basis of. Shearwall isdividedinto a whole walland theassociated shear wall in theactual project,a wholewallfor exampl e, such as generalhousingconstruction in the gableor fish bone structure filmwalls and small openingswall.Coupled Shear walls are connected bythecoupling beam shear wall.Butbecause thegeneralcoupling beamstiffness is less thanthe wall stiffnessof the limbs,so. Walllimb aloneis obvious.The central beam of theinflection pointtopay attentionto thewall pressure than the limits of the limb axis. Will forma shortwide beams,widecolumn wall limbshear wall openings toolarge component atbothen ds with just the domain of variable cross-section ro din the internalforcesunder theactionof many Walllimb inflection point Therefore, the calcula tions and construction shouldAccordingtoapproximate the framestructure to consider.The designof shear walls shouldbe based on the characteristics of avariety ofwall itself,and differentmechanical ch aracteristicsand requirements,wall oftheinternalforcedistribution and failuremodes of specific and comprehensive consideration of the design reinforcement and structural measures. Frame shear wall structure design is to consider the structure of the overall analysis for both directionsofthehorizontal and verticaleffects. Obtain theinternal force is required in accordancewiththe bias or partial pull normal section forcecalculation.The wall structure oftheframe shear wall structural design of the content frame high-rise buildings, in the actual projectintheuse of themost seismic walls have sufficient quantitiesto meet thelimitsof the layer displacement, the location isrelatively flexible. Seismic wall for continuous layout,full-length through.Should bedesigned to avoid the wall mutations in limb length and alignment is notupand down the hole. The sametime.The inside of the hole marginscolumnshould not belessthan300mm inordertoguaranteethelengthof the column as the edgeof the component and constraint edgecomponents.Thebi-direc tional lateral force resisting structural form of vertical andhorizontalwallconnected.Each other as the affinityof the shear wall. For one, two seismic frame she ar walls,even beam highratio should notgreaterthan 5 and a height of not less than400mm.Midline columnand beams,wall midline shouldnotbe greater tha nthe columnwidthof1/4,in order toreduce thetorsional effect of the seismicaction onthecolumn.Otherwisecan be taken tostrengthen thestirrupratio inthe column tomake up.If theshear wall shearspan thanthe big two. Eventhe beamcro ss-height ratiogreaterthan 2.5, then the design pressure of thecut shouldnotmakeabig 0.2. However, if the shearwallshear spanratioof less than two couplingbeams span of less than 2.5, then the shear compres sion ratiois notgreater than 0.15. Theother hand,the bottom ofthe frame shear wallstructure to enhance thedesign should notbe less than200mmand notlessthanstorey 1/16,otherpartsshouldnot be less than 160mm and not less thanstorey 1/20. Aroundthe wall of the frame shear wall structure shouldbe set to the beam or dark beamand the side columntoform a border. Horizontal distributionofshear walls can from the shear effect,this design when building higher longeror framestructure reinforcement should be appropriatelyincreased, especially in the sensitiveparts of the beam position or temperature, stiffnesschange is bestappropriately increased, thenconsideration shouldbe givento the wallverticalreinforcement,because it is mainly from the bending effect, andtake in some multi-storeyshearwall structurereinforcedreinforcement rate -likelessconstrained edgeofthecomponent or components reinforcement of theedge component.References: [1 sad Hayashi,He Yaming. On the shortshear wall high-rise buildingdesign [J].Keyuan, 2008, (O2).高层框架剪力墙结构设计吴继成摘要: 本文从框架剪力墙结构设计的基本概念人手, 分析了框架剪力墙的构造设计内容, 包括抗震墙、剪跨比等的设计, 并出混凝土结构中最常用的框架剪力墙结构设计的注意要点。

本科毕业设计(论文)英文翻译

本科毕业设计(论文)英文翻译

本科毕业设计(论文)英文翻译要求
英文原文和翻译均作为毕业论文附录,同时给出英文原文的出处,如果是网上下载的原文请给出网址。

具体要求如下:
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外文翻译应包括,外文题目,作者、出版日期和出版社,翻译内容的起止页码,外文原文,然后是中文题目,作者、出版日期和出版社,中文翻译。

外文翻译所用的文献,应主要选自学术期刊或学术会议的文章,其次是教科书或其他书籍。

(撰写论文时,要求参考文献中要有1-2篇外文文献。


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框架结构的抗震设计思路外文文献翻译

框架结构的抗震设计思路外文文献翻译

文献信息:文献标题:Frame Structure Anti-earthquake Design Way of Thinking (框架结构的抗震设计思路)国外作者:Theodore V.Galambos文献出处:《Journal of Constructional Concrete Research》,2000, 55:289-303 字数统计:英文4451单词,22990字符;中文5601汉字外文文献:Frame Structure Anti-earthquake Design Way of ThinkingAbstract Currently, the anti-earthquake norms all round the world almost adopt to a kind of way of thinking: The adoption presses the earthquake strong or weak of possible situation to divide the line earthquake cent area; According to everyplace the history occurrence of the area earthquake of covariance result or to geology structure of the history investigate to have to explicit statistics the meaning establish the sport peak in waterproof and quasi-ground value acceleration; Make use of again the reaction acceleration that the acceleration reaction composes different period; Get a design to use acceleration level through earthquake dint adjust met coefficient R. In the meantime, most nations all approve such point,establishing to defend the earthquake intensity level can take to use a different value, choosing to use to establish to defend the earthquake intensity level more and highly, the ductility request of the structure also more low, choose to use to establish to defend earthquake intensity level more and lowly, structure of ductility request more high. The structure ductility guarantee of precondition is the ductility of the member, pass again an effectively reasonable conjunction in adopting a series of measure guarantee member the foundation of the ductility, the structure system choice is reasonable in the meantime, the degree just distributes reasonable of under condition ability basic assurance structure of ductility.Keywords: frame structure; anti-earthquake design; design way of thinking1.Simple Review of Anti-earthquake Design Way of ThinkingThe development that constructs the structure anti- earthquake is along with people all the earthquake move with the structure characteristic of the understanding is continuously thorough but develop gradually, however, from is born up to now the history of a hundred years, have mostly several to develop a stage as follows:(1) Quiet dint stage: It first from a Japanese professor passed to harm to prognosticate the anti- earthquake design theories that put forward with the theories understanding at that time to the limited earthquake, being applicable to only just rigid body structure. It didn't think characteristic and the place difference to consider structure to the influence that constructs structure.(2) Respond the table stage: Along with vibrate to record of obtain and the development of the structure dynamics theories, the Biota professor of the United States put forward flexibility to respond the concept of the table in 1940, respond the table is list the freely flexible system, it was obtain of numerous earthquakes record of encourage, the structure period or respond of the relation, include the acceleration reaction table, the speed responded a table, moved to respond a table. It consider the motive characteristic of the structure, it still is the foundation that all countries norm design earthquake dint takes a value up to now. The calculation of the earthquake function dint usually use shears with the bottom and flaps a decomposition to respond a table a method, flapping a decomposition to respond a table a method of basic define: Suppose the building structure is the line flexibility more freedom degree system, making use principle of flap a decomposition and flap a type, it will solve a freedom degree the earthquake of the flexible system to respond to resolve for solve an independence of etc. the effect single freedom degree flexible system most the heavy earthquake respond. Then begging should in each function affect that flaps a type. At this time, according to consider the way dissimilarity of the earthquake function, adopt a different array, group method, order flexible system to many qualities of the flat surface vibration, it can use a SRSS method, it is according tosuppose the importation earthquake as steady random process, each of a flap reaction is independent mutually but deduce to get; For consider even-twists many qualities that the lotus connect to order flexible system, the adoption CQC method, it lies in with the main differentiation of the SRSS method: Suppose when flat surface vibrate each flap a type independent mutually, and each contribution that flap a type increased along with the frequency high but lower;But even-twist lotus connect hour each flap a frequency span very small, close together and higher flap the frequency of the type and may near to this relativity that will consider a dissimilarity to flap a very much, also have influence of turn round the weight and not necessarily increase along with the frequency high but lower, sometimes higher flap the influence possibility of the type big in lower flap the influence of the type, it will consider more influences that flap a type while comparing SRSS. The bottom shears the dint method in consideration of the special of the structure system to the simplification that flaps a decomposition to respond to compose a method, be the building height not big, took shearing to slice to transform as the lord and the quality to follow height to distribute more even structure with degree just, the structure vibration moved to respond usually with the first flapped a type for lord, and when the first flapped a type to near to in the straight line, can flap a decomposition method simplification to shear the dint method calculation formula for the basic bottom. The level earthquake function that each quality that this basic formula calculation get order can better reflection just degree bigger structure, but when structure the basic period was long, the place characteristic period to compare with hour, the calculation income coping earthquake function be partial to small. of course , the Anti-earthquake Norm provision, be the structure basic period more than 1.4 place characteristic period, at coping additional level earthquake function.(3)the motive theories stage: Along with move understanding and comprehend to the earthquake of deepen continuously, know to some shortage of the reaction table, such as to the earthquake move hold of influence consideration not week, and the exaltation of the calculator function, make the motive method develop gradually, its essence solves a square distance of motive directly, but because of earthquake theground sport acceleration is very irregular, it can't beg for differential calculus square distance, it shuts to match a solution, so adopt number integral calculus method more. Usual way of doing is carry on a continuous cent a segment a processing towards having already record of the earthquake wave, each data all see do the constant, then the function get to structure up, pass an equilibrium and square distance of motive to beg at the moment of the acceleration, speed, move reaction, moving with ex- the acceleration, speed, the segment to carry on folding to add immediately after folding the result for add as the beginning that descends at that time a segment to start a data, pushing according to this kind, end beg structure at the give for low week again and again the earthquake wave under of the acceleration, speed and move the dint reaction variety process.(4) At American Northridge earthquake in 1994 and Japanese Kobe earthquake in 1995 after, the beautiful day scholar put forward again according to the anti- earthquake design method of behavior, it was during the period of usage to make the building structure satisfy various requests that used function according to the basic thought of behavior. Tradition according to the design method dissimilarity of the dint, adjudicate to the structure function mainly is according to move standard, move index sign to come with the different to the structure function to carry on a different control. But descend structure because of the big earthquake of not- flexible transform hard and accurate estimate of, make to can stay around according to the design method of behavior theoretically. But put forward its aggressive meaning to have 2:00 at least:a. Emphasize the system and the society of the earthquake engineering;b. The part that knows an original anti- earthquake to design norm is unsuited to reasonableness.Conduct and actions according to the foundation of the function anti- earthquake design, should to the particular level earthquake function of a certain covariance meaning under of the structure move, the speed and acceleration carry on accurate valuation, should also have a reasonable of valuation method with available valuation tool. It is exactly because of this purpose, put forward and developed the Pushover method and ability to compose a method. The basic way of thinking of the Pushovermethod is an adoption the quiet dint add to carry, supposing the side of the some penny cloth form toward lotus to carry a function on the structure, adding to carry gradually until attain the structure control point target to move or the structure break, getting the level side of the control point to move to shear the dint relation curve with substrate thus, evaluating in order to the anti-vibration ability of the structure. The Pushover method depends on to distribute a form and play the plasticity reaction table target to move to really settle in the side force.2.Basic Way of Thinking of Frame Structure Anti-earthquake Design—ductility StandardAfter the flexibility respond table put forward, the people's detection computes to gain from here of the structure respond with the actual earthquake the breakage phenomenon of the structure contain certain antinomy, mainly is press the flexibility reaction table to calculate of the structure responded the acceleration as habitual to design the earthquake dint to take to be worth big quite a few at that time doubly, and took to settle according to the habitual of the function of the design earthquake dint descends the house structure of design, the harm of the structure system wasn't serious in the earthquake.60's last century, the New mark passed to start to the beginning of different period just degree homology of the single freedom degree the system carried on analysis under the situation that many waves input, put forward etc. moved the principle and etc. energy principle, and put forward the concept of the structure ductility. Studied single and free system to accept defeat the level and flexibility thoroughly again from the relation of flapped the biggest not- flexible motive in the period and structure to respond afterward, this be customarily say of the theories of the R-μ -T effect. Passing these researches, announcing to public the ductility ability and plasticity to consume an ability is a structure Be taking to use to accept defeat level under not high circumstance, at big earthquake under the structure doesn't take place severity to break and doesn't don't tumble down of assurance. Arrive here, concerning the design earthquake dint's taking the basic problem of the value size have to arrive understanding definitely, be the anti- earthquake the earthquake dinttake a value of the size isn't a number of assurance, but with the structure ductility function and consume the ability mechanism related quantity value. Here what to need to be explain BE, designed the earthquake dint to take a value to resolve a problem only, but to the structure ductility function guarantee of the measure have to can also promise, this will at underneath a section discuss.Currently, the anti- earthquake norms all round the world almost adopts so a kind of way of thinking: The adoption presses the earthquake strong or weak of possible situation to divide the line earthquake cent area; According to everyplace the history occurrence of the area earthquake of covariance result or to geology structure of the history investigate to have to explicit statistics the meaning establish the sport peak value in waterproof and quasi- ground value acceleration; Make use of again the reaction acceleration that the acceleration reaction composes different period to descend structure to; get a design to use acceleration level through the earthquake dint adjustment coefficient R. In the meantime, most nations all approve such standpoint, establishing to defend the earthquake intensity level can take to use a different value, choosing to use to establish to defend the earthquake intensity level more and highly, the ductility request of the structure also more low, choose to use to establish to defend the earthquake intensity level more and lowly, structure of ductility request more high. The structure ductility guarantee of precondition is the ductility of the member, pass again an effectively reasonable conjunction in adopting a series of measure guarantee member the foundation of the ductility, the structure system choice is reasonable in the meantime, the degree just distributes reasonable of under condition ability basic assurance structure of ductility.Underneath this kind of discusses the our country anti- earthquake norm mostly way of thinking, the current Chinese norm didn't adopt a variety to establish to defend the earthquake intensity level to take to use, but don’ Ted add a distinction of unify an adoption of the earthquake dint adjustment coefficient R=1/0.35;In the meantime, mostly according to establish a dissimilarity of defend the earthquake intensity, divide the line the different anti- earthquake grade, fix attention on in establish to defend earthquake intensity differently, adopt the anti- earthquake measure of the differentassurance ductility. Very obvious here exist a misunderstanding of concept, also be according to the theories of the R-μ-T effect, the little more than earthquake dint adjustment coefficient R=1/0.35, should give the same ductility guarantee measure to the structure, but the Chinese norm adopt the different ductility guarantee measure, along with anti- earthquake the exaltation of the grade, ductility guarantee the ability correspond to strengthen. This kind of usefulness of the way of doing under way and not the line motive respond of verification, can describe so as a result mostly: For the district of 8 degrees 0.3 g and 9 degrees 0.4 g, because of correspond of the anti- earthquake grade is higher, the measure of the guarantee ductility is also stronger, so generally and more safe; And for the district of 6 degrees 0.05 g and 7 degrees 0.1 g, gain from here to of the level earthquake effect be partial to small, the general lotus carries an array, group is carried the control function by the gravity lotus, although to should of the measure of the guarantee ductility isn't very strong, can also guarantee structure generally under the big earthquake of not- flexible transform of function; But to the district of 7 degrees 0.15 g and 8 degrees 0.2 g, circumstance another the person worry, because of at the lotus carry an array, group, the earthquake function can have generally control function, but correspond measure of guarantee the ductility and be partial to weak, so difficult don't need to exist certain potential safety hazard to suffer from. See again other national earthquake dint adjustment coefficient R to choose to use, in order to have kept concrete understanding of view:The earthquake dint adjustment coefficient of all countries norm provision3.Ability Design MethodTop a part emphasized to discuss the design earthquake dint to take the problem of the value, but wanted to promise structure under the big earthquake of function, also need to establish the valid anti- earthquake measure, make the structure really have need of keep vertical loading under the dint condition not- flexible transform an ability, this be the so-called ability design method.Ability design method from New Zealand the reinforced concrete anti- earthquake expert scholars such as the T. Parlay and the R. Park etc. development with initiate, main way of thinking is to the member occasionally member dissimilarity inside the piece is subjected to the dint form of the loading ability differ of control, promise the reinforced concrete structure formation the beam swing joint organization and ductility bigger is cut noodles to be subjected to the dint breakage appearance, make the structure have to play plasticity to transform function enough, promise big earthquake hour have an enough ability to consume to spread function, avoid creation brittleness to break and appear disadvantageous of organization form. The key of the ability design method is the anti- earthquake design that leads the control concept into structure, there is the leading formation of the purpose to the beneficial breakage mechanism is to the structure and break mode, avoid not reasonable of the structure break appearance, and try assurance to anticipate to break part to play plasticity to transform an ability.The ability design method mainly passes the following three kinds of measure to give assurance:1. Enlarge pillar opposite in the anti- of the beam-curved ability, artificial of leading of the structure swing joint part.2. Raise opposite in is cut the noodles loading dint of the anti- shear ability, avoiding appearing non- ductility to shear to slice breakage.3. To the part that appears the plasticity swing probably, the adoption corresponds of structure measure, assurance necessity of not- flexible transform function.First, the reasonable part of the swing joint carry on a discussion, all countriesmostly of the way of thinking inclines toward to make the project that the beam carries first to carry to appear in the pillar about and all. This kind of swing joint project has a following advantage: The ductility of the beam is easy to a control, and under general circumstance compare pillar of the ductility is big; The whole plasticity of the beam swing joint ratio pillar swing joint formation transform small; The plasticity of the beam swing joint organization formation transform more stable. There are also two kinds of different design methods while admit the premise of have the initiative the formation beam swing joint, a kind of from is a representative New Zealand of, incline toward the formation ideal beam swing joint organization, be promise the beam carries to appear the plasticity swing, but in addition to first floor, the post all doesn't appear the plasticity swing, at this time to in addition to the first floor pillar give post opposite compare bigger and super and strong coefficient(probably 2.0) in the beam, the advantage is a post(in addition to first floor) and doesn't need to be carry on to go together with hoop complicatedly at this time, because of adopt such coefficient can promise a swing joint very explicit. But is exactly because this kind of design method pursues the ideal beam swing joint organization to cause the first floor post compare weaker, the possibility for throng will be a swing joint, the plasticity that correspond and then have to adopt the structure measure to promise this part transforms function. In the meantime, such as if the first floor the influence of the swing joint upon the structure will compare greatly, once pressing and mating because structural whole tumble down, this has to be given guarantee up from the structure, increasing a structure of difficulty. Another project includes total body, Chinese etc. in the United States, Europe, this kind of project leading structure pillar swing joint the night appears in the beam swing joint, unlimited make the emergence of the swing joint in the meantime, but request structure and do not become the layer side to move structure, at this time to post of super go together with coefficient to compare with to request New Zealand of want to be small, goes together with the project that the stirrup takes in to control to the post adoption in the meantime. BE super to go together with coefficient to really settle problem comparison complications to the post adoption in fact: The beam carries thesuper influence for go together with for construct; The beam carries the plasticity swing to appear inside the dint is heavy to distribute of influence; Before accept defeat of the not- flexible characteristic may make the post bending moment physically big get in the flexibility analysis of bending moment ;The indetermination factor that the material difference bring; Growth of the structure not- flexible characteristic cause the influence etc. that the structure motive characteristic variety bring. According to the request of the ability design, the plastic hinge that shears the dint wall appears generally in the bottom of the wall limb. The joining beam shear the loading dint and ductility that the loading dint and ductility and entrance to cave of the dint wall connect beam contain very great relation, designing generally and possibly weak connect beam, the leading that has intention to know connects beam at earthquake accept defeat first, then is the bottom wall to accept defeat, also be anticipate the area of plastic hinge to accept defeat.Avoided appearing to shear reason of slice the breakage early easy, be because of shearing to slice to break to belong to the brittleness breakage, disadvantage in promise the ductility of the structure, promise of way be according to the dissimilarity of the anti- earthquake grade to all beams, pillars, wall etc. the adoption is opposite to bend in the anti- of different super go together with coefficient.The basic request that the anti- earthquake anti- shear is before the beam carry plastic hinge that big epicenter need turn to move and don't take place to shear to slice breakage, this sheared concept difference with the non- anti- earthquake anti-.For various different processing methods that the structure anti- of the member shears mechanism and the our country norm, there is the necessity elucidation here once. Beam: When anti- shake because of low week again and again the function made the beam appear to cross an inclined fracture, fissure, the inclined fracture, fissure distributed an anti- of come to a decision the anti- earthquake to shear the ability ratio not an anti- earthquake to have to descend, reason: The anti- shake of shear to slice to break occurrence after the end long tendon accept defeat, the fracture, fissure compare at this time greatly; The harm that crosses the emergence of the fracture, fissure to the concrete is more serious; The enlargement beam carried the number of the negativebending moment when anti- shake, cause bigger sheared the dint value to appear under the beam to carry, sprinkle plank now because of descending to carry to have no, break more easily. But at this time the function and function for non- anti- to shake of the stirrup differ only a few, in the norm to the consideration of this disadvantageous function is to adopt to resist to shear formula in to the concrete item 0.6 of fold to reduce, in the meantime, in order not to non- ductility of inclined break bad, while adopting to shake than the non- anti- more scathing restriction measure, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. Pillar: It resist earthquake in the norm the anti- of the pillar shear the processing principle of the formula similar, also is adopt to the concrete item 0.6 of fold and reduce coefficient, adopt more scathing measure to prevent from equally inclined break bad, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. But because of under general circumstance, the stalk pressure comparison of the pillar is big, this kind of pressure shears function to be partial to the anti- of the member after appearing the plastic hinge to the pillar emollient, according to this kind of way of thinking, pillar the adoption fold to reduce with beam similarly to seem to be not greatly reasonable. Wall: When the anti- shake, there is almost no related on trial data in domestic, is an adoption only the earthquake is to the non- anti- of the anti- sheared formula to adopt to the concrete item and the reinforcing bar items 0.8 of fold and reduce coefficient, in the meantime, in bar of and inclined break bad, adoption the restriction shear a way of press the ratio, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. What to need to be explaining BE, under general circumstance, the part that shears the dint wall anti- to shear a problem probably is a lower part are a few floors. Node: The main acceptance shears the dint member, the node shears dint mainly is depend on the truss organization, inclined press pole organization, the stirrup of the stipulation effect three organizations or path to bear. The truss organization mainly is resist the reinforcing bar lord to pull should dint, inclined press the pole organization mainly is the lord that resists the concrete and the reinforcing bar creation to press should dint, the stipulation effect of thestirrup then strengthens the anti- of the concrete to shear ability. Along with the node concrete inside the area not- line development, the truss the function of the structure lets up continuously, and then both of function but be strengthening continuously. Therefore, the main target of the node anti- earthquake is under the situation that be subjected to dint again and again, pass to strengthen inclined press the pole organization and the stirrup to control an effect to avoid the core area concrete inclined to press thus a diplomatic corps to order at attain to anticipate of the big earthquake respond before do not take place to shear to slice breakage.After shearing the discussion of mechanism to the above anti-earthquake, can be do with the function of the beam stirrup to tally up as follows: The first obvious function is to used for an anti- to shear; The second function controls concrete, this to guarantee the structure ductility contain count for much function, can also say literally here the obstacle that once high and strong concrete meet when used for anti- earthquake, this is related with the material of the high and strong concrete first, strength more high concrete more frailty, its should attain in the dint contingency relation biggest press should the contingency of the dint is smaller, this makes the design become the ductility member a difficulty with very great formation, is more high because of the strength of the concrete in the meantime, the stirrup rises the effect of the stipulation more bad, also can't the extreme limit of the enough valid exaltation concrete press a contingency, so cause to adopt the ductility of the structure member of the high and strong concrete hard get a guarantee; The third function is the stipulation function that carries to the beam lengthways reinforcing bar, prevent forming lengthways reinforcing bar lose steady, this has something to do with the special material of the reinforcing bar.中文译文:框架结构的抗震设计思路摘要目前,世界各国的抗震规范都采用这种思路:按可遇地震的强弱划分地震分区;根据各地区的历史发生地震的统计或对地质构造的考察得出设防水准地面的运动峰值加速度;再利用加速度反应谱给出不同周期下结构的反应加速度;通过地震力调整系数R得到设计加速度水准。

毕业论文框架结构

毕业论文框架结构

毕业论文框架结构毕业论文是一篇系统性的研究报告或学术论文,需要合理的结构安排才能更好地展示研究成果。

下面是一种常见的毕业论文框架结构:一、引言部分(Introduction)引言部分主要介绍研究背景、研究目的、研究方法和研究意义等内容。

同时,引言还可以包括文献综述,即对相关领域内已有研究成果的概述和评价。

二、研究方法部分(Methods)研究方法部分详细描述了研究所采用的方法和技术,包括实验设计、数据采集和处理方法等。

该部分的目的是确保研究的可靠性和可重复性。

三、结果与分析部分(Results and Analysis)结果与分析部分是整个论文的核心内容,展示了研究过程中所得到的数据和研究结果。

可以通过图表、数据统计和科学分析等方式进行展示,同时需要对结果进行客观的分析和解释。

四、讨论部分(Discussion)讨论部分是对结果与分析进行深入解读和探讨的部分。

可以分析研究结果与预期目标的一致性、存在的问题及原因等方面。

同时,可以提出自己的观点和建议,为学术界提供对于相关问题的参考和启示。

五、结论部分(Conclusion)结论部分是对整篇论文的总结和归纳,强调研究的创新点和成果,并指出对于未来研究的启示和建议。

六、参考文献(References)参考文献部分列出了研究过程中所引用的文献和资料信息,遵循相应的引用格式要求。

七、附录(Appendix)附录部分包括对于论文中某些细节的补充说明,如研究材料的详细描述、数据的原始记录、调查问卷等。

以上是一种常见的毕业论文框架结构,每部分的篇幅和重要性可以根据实际情况进行调整。

希望对你的论文写作有所帮助!。

框架结构设计外文翻译

框架结构设计外文翻译

南京理工大学紫金学院毕业设计(论文)外文资料翻译系:机械工程系专业:土木工程姓名:袁洲学号: 050105140 外文出处:Design of prestressed(用外文写)concrete structures 附件: 1.外文资料翻译译文;2.外文原文。

附件1:外文资料翻译译文8-2简支梁布局一个简单的预应力混凝土梁由两个危险截面控制:最大弯矩截面和端截面。

这两部分设计好之后,中间截面一定要单独检查,必要时其他部位也要单独调查。

最大弯矩截面在以下两种荷载阶段为控制情况,即传递时梁受最小弯矩M G的初始阶段和最大设计弯矩M T时的工作荷载阶段。

而端截面则由抗剪强度、支承垫板、锚头间距和千斤顶净空所需要的面积来决定。

所有的中间截面是由一个或多个上述要求,根它们与上述两种危险截面的距离来控制。

对于后张构件的一种常见的布置方式是在最大弯矩截面采用诸如I形或T形的截面,而在接近梁端处逐渐过渡到简单的矩形截面。

这就是人们通常所说的后张构件的端块。

对于用长线法生产的先张构件,为了便于生产,全部只用一种等截面,其截面形状则可以为I形、双T形或空心的。

在第5 、 6 和7章节中已经阐明了个别截面的设计,下面论述简支梁钢索的总布置。

梁的布置可以用变化混凝土和钢筋的办法来调整。

混凝土的截面在高度、宽度、形状和梁底面或者顶面的曲率方面都可以有变化。

而钢筋只在面积方面有所变化,不过在相对于混凝土重心轴线的位置方面却多半可以有变化。

通过调整这些变化因素,布置方案可能有许多组合,以适应不同的荷载情况。

这一点是与钢筋混凝土梁是完全不同的,在钢筋混凝土梁的通常布置中,不是一个统一的矩形截面便是一个统一的T形,而钢筋的位置总是布置得尽量靠底面纤维。

首先考虑先张梁,如图 8-7,这里最好采用直线钢索,因为它们在两个台座之间加力比较容易。

我们先从图(a)的等截面直梁的直线钢索开始讨论。

这样的布置都很简单,但这样一来,就不是很经济的设计了,因为跨中和梁端的要求会产生冲突。

毕设外文文献+翻译1

毕设外文文献+翻译1

外文翻译外文原文CHANGING ROLES OF THE CLIENTS、ARCHITECTSAND CONTRACTORS THROUGH BIMAbstract:Purpose –This paper aims to present a general review of the practical implications of building information modelling (BIM) based on literature and case studies. It seeks to address the necessity for applying BIM and re-organising the processes and roles in hospital building projects. This type of project is complex due to complicated functional and technical requirements, decision making involving a large number of stakeholders, and long-term development processes.Design/methodology/approach–Through desk research and referring to the ongoing European research project InPro, the framework for integrated collaboration and the use of BIM are analysed.Findings –One of the main findings is the identification of the main factors for a successful collaboration using BIM, which can be recognised as “POWER”: product information sharing (P),organisational roles synergy (O), work processes coordination (W), environment for teamwork (E), and reference data consolidation (R).Originality/value –This paper contributes to the actual discussion in science and practice on the changing roles and processes that are required to develop and operate sustainable buildings with the support of integrated ICT frameworks and tools. It presents the state-of-the-art of European research projects and some of the first real cases of BIM application in hospital building projects.Keywords:Europe, Hospitals, The Netherlands, Construction works, Response flexibility, Project planningPaper type :General review1. IntroductionHospital building projects, are of key importance, and involve significant investment, and usually take a long-term development period. Hospital building projects are also very complex due to the complicated requirements regarding hygiene, safety, special equipments, and handling of a large amount of data. The building process is very dynamic and comprises iterative phases and intermediate changes. Many actors with shifting agendas, roles and responsibilities are actively involved, such as: the healthcare institutions, national and local governments, project developers, financial institutions, architects, contractors, advisors, facility managers, and equipment manufacturers and suppliers. Such building projects are very much influenced, by the healthcare policy, which changes rapidly in response to the medical, societal and technological developments, and varies greatly between countries (World Health Organization, 2000). In The Netherlands, for example, the way a building project in the healthcare sector is organised is undergoing a major reform due to a fundamental change in the Dutch health policy that was introduced in 2008.The rapidly changing context posts a need for a building with flexibility over its lifecycle. In order to incorporate life-cycle considerations in the building design, construction technique, and facility management strategy, a multidisciplinary collaboration is required. Despite the attempt for establishing integrated collaboration, healthcare building projects still faces serious problems in practice, such as: budget overrun, delay, and sub-optimal quality in terms of flexibility, end-user’s dissatisfaction, and energy inefficiency. It is evident that the lack of communication and coordination between the actors involved in the different phases of a building project is among the most important reasons behind these problems. The communication between different stakeholders becomes critical, as each stakeholder possesses different setof skills. As a result, the processes for extraction, interpretation, and communication of complex design information from drawings and documents are often time-consuming and difficult. Advanced visualisation technologies, like 4D planning have tremendous potential to increase the communication efficiency and interpretation ability of the project team members. However, their use as an effective communication tool is still limited and not fully explored. There are also other barriers in the information transfer and integration, for instance: many existing ICT systems do not support the openness of the data and structure that is prerequisite for an effective collaboration between different building actors or disciplines.Building information modelling (BIM) offers an integrated solution to the previously mentioned problems. Therefore, BIM is increasingly used as an ICT support in complex building projects. An effective multidisciplinary collaboration supported by an optimal use of BIM require changing roles of the clients, architects, and contractors; new contractual relationships; and re-organised collaborative processes. Unfortunately, there are still gaps in the practical knowledge on how to manage the building actors to collaborate effectively in their changing roles, and to develop and utilise BIM as an optimal ICT support of the collaboration.This paper presents a general review of the practical implications of building information modelling (BIM) based on literature review and case studies. In the next sections, based on literature and recent findings from European research project InPro, the framework for integrated collaboration and the use of BIM are analysed. Subsequently, through the observation of two ongoing pilot projects in The Netherlands, the changing roles of clients, architects, and contractors through BIM application are investigated. In conclusion, the critical success factors as well as the main barriers of a successful integrated collaboration using BIM are identified.2. Changing roles through integrated collaboration and life-cycle design approachesA hospital building project involves various actors, roles, and knowledge domains. In The Netherlands, the changing roles of clients, architects, and contractors in hospital building projects are inevitable due the new healthcare policy. Previously under the Healthcare Institutions Act (WTZi), healthcare institutions were required to obtain both a license and a building permit for new construction projects and major renovations. The permit was issued by the Dutch Ministry of Health. The healthcare institutions were then eligible to receive financial support from the government. Since 2008, new legislation on the management of hospital building projects and real estate has come into force. In this new legislation, a permit for hospital building project under the WTZi is no longer obligatory, nor obtainable (Dutch Ministry of Health, Welfare and Sport, 2008). This change allows more freedom from the state-directed policy, and respectively, allocates more responsibilities to the healthcare organisations to deal with the financing and management of their real estate. The new policy implies that the healthcare institutions are fully responsible to man age and finance their building projects and real estate. The government’s support for the costs of healthcare facilities will no longer be given separately, but will be included in the fee for healthcare services. This means that healthcare institutions must earn back their investment on real estate through their services. This new policy intends to stimulate sustainable innovations in the design, procurement and management of healthcare buildings, which will contribute to effective and efficient primary healthcare services.The new strategy for building projects and real estate management endorses an integrated collaboration approach. In order to assure the sustainability during construction, use, and maintenance, the end-users, facility managers, contractors and specialist contractors need to be involved in the planning and design processes. The implications of the new strategy are reflected in the changing roles of the building actors and in the new procurement method.In the traditional procurement method, the design, and its details, are developed by the architect, and design engineers. Then, the client (the healthcare institution) sends an application to the Ministry of Healthto obtain an approval on the building permit and the financial support from the government. Following this, a contractor is selected through a tender process that emphasises the search for the lowest-price bidder. During the construction period, changes often take place due to constructability problems of the design and new requirements from the client. Because of the high level of technical complexity, and moreover, decision-making complexities, the whole process from initiation until delivery of a hospital building project can take up to ten years time. After the delivery, the healthcare institution is fully in charge of the operation of the facilities. Redesigns and changes also take place in the use phase to cope with new functions and developments in the medical world.The integrated procurement pictures a new contractual relationship between the parties involved in a building project. Instead of a relationship between the client and architect for design, and the client and contractor for construction, in an integrated procurement the client only holds a contractual relationship with the main party that is responsible for both design and construction. The traditional borders between tasks and occupational groups become blurred since architects, consulting firms, contractors, subcontractors, and suppliers all stand on the supply side in the building process while the client on the demand side. Such configuration puts the architect, engineer and contractor in a very different position that influences not only their roles, but also their responsibilities, tasks and communication with the client, the users, the team and other stakeholders.The transition from traditional to integrated procurement method requires a shift of mindset of the parties on both the demand and supply sides. It is essential for the client and contractor to have a fair and open collaboration in which both can optimally use their competencies. The effectiveness of integrated collaboration is also determined by the client’s capacity and strategy to organize innovative tendering procedures.A new challenge emerges in case of positioning an architect in a partnership with the contractor instead of with the client. In case of the architect enters a partnership with the contractor, an important issues is how to ensure the realisation of the architectural values as well as innovative engineering through an efficient construction process. In another case, the architect can stand at the client’s side in a strategic advisory role instead of being the designer. In this case, the architect’s responsibility is translating client’s requirements and wishes into the architectural values to be included in the design specification, and evaluating the contractor’s proposal against this. In any of this new role, the architect holds the responsibilities as stakeholder interest facilitator, custodian of customer value and custodian of design models.The transition from traditional to integrated procurement method also brings consequences in the payment schemes. In the traditional building process, the honorarium for the architect is usually based on a percentage of the project costs; this may simply mean that the more expensive the building is, the higher the honorarium will be. The engineer receives the honorarium based on the complexity of the design and the intensity of the assignment. A highly complex building, which takes a number of redesigns, is usually favourable for the engineers in terms of honorarium. A traditional contractor usually receives the commission based on the tender to construct the building at the lowest price by meeting the minimum specifications given by the client. Extra work due to modifications is charged separately to the client. After the delivery, the contractor is no longer responsible for the long-term use of the building. In the traditional procurement method, all risks are placed with the client.In integrated procurement method, the payment is based on the achieved building performance; thus, the payment is non-adversarial. Since the architect, engineer and contractor have a wider responsibility on the quality of the design and the building, the payment is linked to a measurement system of the functional and technical performance of the building over a certain period of time. The honorarium becomes an incentive to achieve the optimal quality. If the building actors succeed to deliver a higher added-value thatexceed the minimum client’s requirements, they will receive a bonus in accordance to the client’s extra gain. The level of transparency is also improved. Open book accounting is an excellent instrument provided that the stakeholders agree on the information to be shared and to its level of detail (InPro, 2009).Next to the adoption of integrated procurement method, the new real estate strategy for hospital building projects addresses an innovative product development and life-cycle design approaches. A sustainable business case for the investment and exploitation of hospital buildings relies on dynamic life-cycle management that includes considerations and analysis of the market development over time next to the building life-cycle costs (investment/initial cost, operational cost, and logistic cost). Compared to the conventional life-cycle costing method, the dynamic life-cycle management encompasses a shift from focusing only on minimizing the costs to focusing on maximizing the total benefit that can be gained. One of the determining factors for a successful implementation of dynamic life-cycle management is the sustainable design of the building and building components, which means that the design carries sufficient flexibility to accommodate possible changes in the long term (Prins, 1992).Designing based on the principles of life-cycle management affects the role of the architect, as he needs to be well informed about the usage scenarios and related financial arrangements, the changing social and physical environments, and new technologies. Design needs to integrate people activities and business strategies over time. In this context, the architect is required to align the design strategies with the organisational, local and global policies on finance, business operations, health and safety, environment, etc.The combination of process and product innovation, and the changing roles of the building actors can be accommodated by integrated project delivery or IPD (AIA California Council, 2007). IPD is an approach that integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to reduce waste and optimize efficiency through all phases of design, fabrication and construction. IPD principles can be applied to a variety of contractual arrangements. IPD teams will usually include members well beyond the basic triad of client, architect, and contractor. At a minimum, though, an Integrated Project should include a tight collaboration between the client, the architect, and the main contractor ultimately responsible for construction of the project, from the early design until the project handover. The key to a successful IPD is assembling a team that is committed to collaborative processes and is capable of working together effectively. IPD is built on collaboration. As a result, it can only be successful if the participants share and apply common values and goals.3. Changing roles through BIM applicationBuilding information model (BIM) comprises ICT frameworks and tools that can support the integrated collaboration based on life-cycle design approach. BIM is a digital representation of physical and functional characteristics of a facility. As such it serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its lifecycle from inception onward (National Institute of Building Sciences NIBS, 2007). BIM facilitates time and place independent collaborative working. A basic premise of BIM is collaboration by different stakeholders at different phases of the life cycle of a facility to insert, extract, update or modify information in the BIM to support and reflect the roles of that stakeholder. BIM in its ultimate form, as a shared digital representation founded on open standards for interoperability, can become a virtual information model to be handed from the design team to the contractor and subcontractors and then to the client.BIM is not the same as the earlier known computer aided design (CAD). BIM goes further than an application to generate digital (2D or 3D) drawings. BIM is an integrated model in which all process and product information is combined, stored, elaborated, and interactively distributed to all relevant building actors. As a central model for all involved actors throughout the project lifecycle, BIM develops andevolves as the project progresses. Using BIM, the proposed design and engineering solutions can be measured against the client’s requirements and expected building performance. The functionalities of BIM to support the design process extend to multidimensional (nD), including: three-dimensional visualisation and detailing, clash detection, material schedule, planning, cost estimate, production and logistic information, and as-built documents. During the construction process, BIM can support the communication between the building site, the factory and the design office– which is crucial for an effective and efficient prefabrication and assembly processes as well as to prevent or solve problems related to unforeseen errors or modifications. When the building is in use, BIM can be used in combination with the intelligent building systems to provide and maintain up-to-date information of the building performance, including the life-cycle cost.To unleash the full potential of more efficient information exchange in the AEC/FM industry in collaborative working using BIM, both high quality open international standards and high quality implementations of these standards must be in place. The IFC open standard is generally agreed to be of high quality and is widely implemented in software. Unfortunately, the certification process allows poor quality implementations to be certified and essentially renders the certified software useless for any practical usage with IFC. IFC compliant BIM is actually used less than manual drafting for architects and contractors, and show about the same usage for engineers. A recent survey shows that CAD (as a closed-system) is still the major form of technique used in design work (over 60 per cent) while BIM is used in around 20 percent of projects for architects and in around 10 per cent of projects for engineers and contractors.The application of BIM to support an optimal cross-disciplinary and cross-phase collaboration opens a new dimension in the roles and relationships between the building actors. Several most relevant issues are: the new role of a model manager; the agreement on the access right and Intellectual Property Right (IPR); the liability and payment arrangement according to the type of contract and in relation to the integrated procurement; and the use of open international standards.Collaborative working using BIM demands a new expert role of a model manager who possesses ICT as well as construction process know-how (InPro, 2009). The model manager deals with the system as well as with the actors. He provides and maintains technological solutions required for BIM functionalities, manages the information flow, and improves the ICT skills of the stakeholders. The model manager does not take decisions on design and engineering solutions, nor the organisational processes, but his roles in the chain of decision making are focused on:the development of BIM, the definition of the structure and detail level of the model, and the deployment of relevant BIM tools, such as for models checking, merging, and clash detections;the contribution to collaboration methods, especially decision making and communication protocols, task planning, and risk management;and the management of information, in terms of data flow and storage, identification of communication errors, and decision or process (re-)tracking.Regarding the legal and organisational issues, one of the actual questions is: “In what way does the intellectual property right (IPR) in collaborative working using BIM differ from the IPR in a traditional teamwork?”. In terms of combined work, the IPR of each element is at tached to its creator. Although it seems to be a fully integrated design, BIM actually resulted from a combination of works/elements; for instance: the outline of the building design, is created by the architect, the design for the electrical system, is created by the electrical contractor, etc. Thus, in case of BIM as a combined work, the IPR is similar to traditional teamwork. Working with BIM with authorship registration functionalities may actually make it easier to keep track of the IPR.How does collaborative working, using BIM, effect the contractual relationship? On the one hand,collaborative working using BIM does not necessarily change the liability position in the contract nor does it obligate an alliance contract. The General Principles of BIM A ddendum confirms: ‘This does not effectuate or require a restructuring of contractual relationships or shifting of risks between or among the Project Participants other than as specifically required per the Protocol Addendum and its Attachments’ (ConsensusDOCS, 2008). On the other hand, changes in terms of payment schemes can be anticipated. Collaborative processes using BIM will lead to the shifting of activities from to the early design phase. Much, if not all, activities in the detailed engineering and specification phase will be done in the earlier phases. It means that significant payment for the engineering phase, which may count up to 40 per cent of the design cost, can no longer be expected. As engineering work is done concurrently with the design, a new proportion of the payment in the early design phase is necessary.4. Review of ongoing hospital building projects using BIMIn The Netherlands, the changing roles in hospital building projects are part of the strategy, which aims at achieving a sustainable real estate in response to the changing healthcare policy. Referring to literature and previous research, the main factors that influence the success of the changing roles can be concluded as: the implementation of an integrated procurement method and a life-cycle design approach for a sustainable collaborative process; the agreement on the BIM structure and the intellectual rights; and the integration of the role of a model manager. The preceding sections have discussed the conceptual thinking on how to deal with these factors effectively. This current section observes two actual projects and compares the actual practice with the conceptual view respectively.The main issues, which are observed in the case studies, are:the selected procurement method and the roles of the involved parties within this method;the implementation of the life-cycle design approach;the type, structure, and functionalities of BIM used in the project;the openness in data sharing and transfer of the model, and the intended use of BIM in the future; and the roles and tasks of the model manager.The pilot experience of hospital building projects using BIM in the Netherlands can be observed at University Medical Centre St Radboud (further referred as UMC) and Maxima Medical Centre (further referred as MMC). At UMC, the new building project for the Faculty of Dentistry in the city of Nijmegen has been dedicated as a BIM pilot project. At MMC, BIM is used in designing new buildings for Medical Simulation and Mother-and-Child Centre in the city of Veldhoven.The first case is a project at the University Medical Centre (UMC) St Radboud. UMC is more than just a hospital. UMC combines medical services, education and research. More than 8500 staff and 3000 students work at UMC. As a part of the innovative real estate strategy, UMC has considered to use BIM for its building projects. The new development of the Faculty of Dentistry and the surrounding buildings on the Kapittelweg in Nijmegen has been chosen as a pilot project to gather practical knowledge and experience on collaborative processes with BIM support.The main ambition to be achieved through the use of BIM in the building projects at UMC can be summarised as follows:using 3D visualisation to enhance the coordination and communication among the building actors, and the user participation in design;integrating the architectural design with structural analysis, energy analysis, cost estimation, and planning;interactively evaluating the design solutions against the programme of requirements and specifications;reducing redesign/remake costs through clash detection during the design process; andoptimising the management of the facility through the registration of medical installations andequipments, fixed and flexible furniture, product and output specifications, and operational data.The second case is a project at the Maxima Medical Centre (MMC). MMC is a large hospital resulted from a merger between the Diaconessenhuis in Eindhoven and St Joseph Hospital in Veldhoven. Annually the 3,400 staff of MMC provides medical services to more than 450,000 visitors and patients. A large-scaled extension project of the hospital in Veldhoven is a part of its real estate strategy. A medical simulation centre and a women-and-children medical centre are among the most important new facilities within this extension project. The design has been developed using 3D modelling with several functionalities of BIM.The findings from both cases and the analysis are as follows. Both UMC and MMC opted for a traditional procurement method in which the client directly contracted an architect, a structural engineer, and a mechanical, electrical and plumbing (MEP) consultant in the design team. Once the design and detailed specifications are finished, a tender procedure will follow to select a contractor. Despite the choice for this traditional method, many attempts have been made for a closer and more effective multidisciplinary collaboration. UMC dedicated a relatively long preparation phase with the architect, structural engineer and MEP consultant before the design commenced. This preparation phase was aimed at creating a common vision on the optimal way for collaboration using BIM as an ICT support. Some results of this preparation phase are: a document that defines the common ambition for the project and the collaborative working process and a semi-formal agreement that states the commitment of the building actors for collaboration. Other than UMC, MMC selected an architecture firm with an in-house engineering department. Thus, the collaboration between the architect and structural engineer can take place within the same firm using the same software application.Regarding the life-cycle design approach, the main attention is given on life-cycle costs, maintenance needs, and facility management. Using BIM, both hospitals intend to get a much better insight in these aspects over the life-cycle period. The life-cycle sustainability criteria are included in the assignments for the design teams. Multidisciplinary designers and engineers are asked to collaborate more closely and to interact with the end-users to address life-cycle requirements. However, ensuring the building actors to engage in an integrated collaboration to generate sustainable design solutions that meet the life-cycle performance expectations is still difficult. These actors are contracted through a traditional procurement method. Their tasks are specific, their involvement is rather short-term in a certain project phase, their responsibilities and liabilities are limited, and there is no tangible incentive for integrated collaboration.From the current progress of both projects, it can be observed that the type and structure of BIM relies heavily on the choice for BIM software applications. Revit Architecture and Revit Structure by Autodesk are selected based on the argument that it has been widely used internationally and it is compatible with AutoCAD, a widely known product of the same software manufacturer. The compatibility with AutoCAD is a key consideration at MMC since the drawings of the existing buildings were created with this application. These 2D drawings were then used as the basis to generate a 3D model with the BIM software application. The architectural model generated with Revit Architecture and the structural model generated by Revit Structure can be linked directly. In case of a change in the architectural model, a message will be sent to the structural engineer. He can then adjust the structural model, or propose a change in return to the architect, so that the structural model is always consistent with the architectural one.Despite the attempt of the design team to agree on using the same software application, the MEP consultant is still not capable to use Revit; and therefore, a conversion of the model from and to Revit is still required. Another weakness of this “closed approach”, which is dependent to the use of the same software applications, may appear in the near future when the project further progresses into the construction phase. If the contractor uses another software application, considerable extra work will be needed to make the model creted during the design phase to be compatible for use in the construction phase.。

英文论文(外文文献)翻译成中文的格式与方法

英文论文(外文文献)翻译成中文的格式与方法

英文论文(外文文献)翻译成中文的格式与方法英文论文(外文文献)翻译成中文的格式与方法本文关键词:外文,英文,中文,翻译成,文献英文论文(外文文献)翻译成中文的格式与方法本文简介:在撰写毕业设计(论文)或科研论文时,需要参考一些相关外文文献,了解国外的最新研究进展,这就需要我们找到最新最具代表性的外文文献,进行翻译整理,以备论文写作时参考,外文文献中英文文献占绝大多数,因此英文论文准确的翻译成中文就显得尤为重要!一、外文文献从哪里下载1、从知网国际文献总库中找英文论文(外文文献)翻译成中文的格式与方法本文内容:在撰写毕业设计(论文)或科研论文时,需要参考一些相关外文文献,了解国外的最新研究进展,这就需要我们找到最新最具代表性的外文文献,进行翻译整理,以备论文写作时参考,外文文献中英文文献占绝大多数,因此英文论文准确的翻译成中文就显得尤为重要!一、外文文献从哪里下载1、从知网国际文献总库中找,该数据库中包含14,000多家国外出版社的文献,囊括所有专业的英文文献资料。

2、一些免费的外文数据库或网站,为了方便大家查找,编者整理成文档供大家下载:国外免费文献数据库大全下载3、谷歌学术检索工具,检索时设置成只检索英文文献,键入与专业相关的关键词即可检索。

二、英文论文翻译格式与要求翻译的外文文献的字符要求不少于1.5万(或翻译成中文后至少在3000字以上)。

字数达到的文献一篇即可。

翻译的外文文献应主要选自学术期刊、学术会议的文章、有关着作及其他相关材料,应与毕业论文(设计)主题相关,并作为外文参考文献列入毕业论文(设计)的参考文献。

并在每篇中文译文首页用"脚注"形式注明原文作者及出处,中文译文后应附外文原文。

需认真研读和查阅术语完成翻译,不得采用翻译软件翻译。

中文译文的编排结构与原文同,撰写格式参照毕业论文的格式要求。

参考文献不必翻译,直接使用原文的(字体,字号,标点符号等与毕业论文中的参考文献要求同),参考文献的序号应标注在译文中相应的地方。

结构设计--中英文翻译

结构设计--中英文翻译

外文翻译结构设计结构设计Augustine J.Fredrich摘要:结构设计是选择材料和构件类型,大小和形状以安全有用的样式承担荷载。

一般说来,结构设计暗指结构物如建筑物和桥或是可移动但有刚性外壳如船体和飞机框架的工厂稳定性。

设计的移动时彼此相连的设备(连接件),一般被安排在机械设计领域。

关键词:结构设计;结构分析;结构方案;工程要求Abstract: Structure design is the selection of materials and member type ,size, and configuration to carry loads in a safe and serviceable fashion .In general ,structural design implies the engineering of stationary objects such as buildings and bridges ,or objects that maybe mobile but have a rigid shape such as ship hulls and aircraft frames. Devices with parts planned to move with relation to each other(linkages) are generally assigned to the area of mechanical .Key words: Structure Design ;Structural analysis ;structural scheme ;Project requirementsStructure DesignStructural design involved at least five distinct phases of work: project requirements, materials, structural scheme, analysis, and design. For unusualstructures or materials a six phase, testing, should be included. These phases do not proceed in a rigid progression , since different materials can be most effective in different schemes , testing can result in change to a design , and a final design is often reached by starting with a rough estimated design , then looping through several cycles of analysis and redesign . Often, several alternative designs will prove quite close in cost, strength, and serviceability. The structural engineer, owner, or end user would then make a selection based on other considerations.Project requirements. Before starting design, the structural engineer must determine the criteria for acceptable performance. The loads or forces to be resisted must be provided. For specialized structures, this may be given directly, as when supporting a known piece of machinery, or a crane of known capacity. For conventional buildings, buildings codes adopted on a municipal, county , or , state level provide minimum design requirements for live loads (occupants and furnishings , snow on roofs , and so on ). The engineer will calculate dead loads (structural and known, permanent installations ) during the design process.For the structural to be serviceable or useful , deflections must also be kept within limits ,since it is possible for safe structural to be uncomfortable “bounce”Very tight deflection limits are set on supports for machinery , since beam sag can cause drive shafts to bend , bearing to burn out , parts to misalign , and overhead cranes to stall . Limitations of sag less than span /1000 ( 1/1000 of the beam length ) are not uncommon . In conventional buildings, beams supporting ceilings often have sag limits of span /360 to avoid plaster cracking, or span /240 to avoid occupant concern (keep visual perception limited ). Beam stiffness also affects floor “bounciness,” which can be annoying if not controlled. In addition , lateral deflection , sway , or drift of tall buildings is often held within approximately height /500 (1/500 of the building height ) to minimize the likelihood of motion discomfort in occupants of upper floors on windy days .Member size limitations often have a major effect on the structural design. For example, a certain type of bridge may be unacceptable because of insufficient under clearance for river traffic, or excessive height endangering aircraft. In building design,ceiling heights and floor-to-floor heights affect the choice of floor framing. Wall thicknesses and column sizes and spacing may also affect the serviceability of various framing schemes.Materials selection. Technological advances have created many novel materials such as carbon fiber and boron fiber-reinforced composites, which have excellent strength, stiffness, and strength-to-weight properties. However, because of the high cost and difficult or unusual fabrication techniques required , they are used only in very limited and specialized applications . Glass-reinforced composites such as fiberglass are more common, but are limited to lightly loaded applications. The main materials used in structural design are more prosaic and include steel, aluminum, reinforced concrete, wood , and masonry .Structural schemes. In an actual structural, various forces are experienced by structural members , including tension , compression , flexure (bending ), shear ,and torsion (twist) . However, the structural scheme selected will influence which of these forces occurs most frequently, and this will influence the process of materials selection.Tension is the most efficient way to resist applied loads ,since the entire member cross section is acting to full capacity and bucking is not a concern . Any tension scheme must also included anchorages for the tension members . In a suspension bridge , for example ,the anchorages are usually massive dead weights at the ends of the main cables . To avoid undesirable changes in geometry under moving or varying loads , tension schemes also generally require stiffening beams or trusses.Compression is the next most efficient method for carrying loads . The full member cross section is used ,but must be designed to avoid bucking ,either by making the member stocky or by adding supplementary bracing . Domed and arched buildings ,arch bridges and columns in buildings frames are common schemes . Arches create lateral outward thrusts which must be resisted . This can be done by designing appropriate foundations or , where the arch occurs above the roadway or floor line , by using tension members along the roadway to tie the arch endstogether ,keeping them from spreading . Compression members weaken drastically when loads are not applied along the member axis , so moving , variable , and unbalanced loads must be carefully considered.Schemes based on flexure are less efficient than tension and compression ,since the flexure or bending is resisted by one side of the member acting in tension while the other side acts in compression . Flexural schemes such as beams , girders , rigid frames , and moment (bending ) connected frames have advantages in requiring no external anchorages or thrust restrains other than normal foundations ,and inherent stiffness and resistance to moving ,variable , and unbalanced loads .Trusses are an interesting hybrid of the above schemes . They are designed to resist loads by spanning in the manner of a flexural member, but act to break up the load into a series of tension and compression forces which are resisted by individually designed tension and have excellent stiffness and resistance to moving and variable loads . Numerous member-to-member connections, supplementary compression braces ,and a somewhat cluttered appearance are truss disadvantages .Plates and shells include domes ,arched vaults ,saw tooth roofs , hyperbolic paraboloids , and saddle shapes .Such schemes attempt to direct all force along the plane of the surface ,and act largely in shear . While potentially very efficient ,such schemes have very strict limitations on geometry and are poor in resisting point ,moving , and unbalanced loads perpendicular to the surface.Stressed-skin and monologue construction uses the skin between stiffening ribs ,spars ,or columns to resist shear or axial forces . Such design is common in airframes for planes and rockets, and in ship hulls . it has also been used to advantage in buildings. Such a design is practical only when the skin is a logical part of the design and is never to be altered or removed .For bridges , short spans are commonly girders in flexure . As spans increase and girder depth becomes unwieldy , trusses are often used ,as well as cablestayed schemes .Longer spans may use arches where foundation conditions ,under clearance ,or headroom requirements are favorable .The longest spans are handled exclusively by suspension schemes ,since these minimize the crucial dead weight andcan be erected wire by wire .For buildings, short spans are handled by slabs in flexure .As spans increase, beams and girders in flexure are used . Longer spans require trusses ,especially in industrial buildings with possible hung loads . Domes ,arches , and cable-suspended and air –supported roofs can be used over convention halls and arenas to achieve clear areas .Structural analysis . Analysis of structures is required to ensure stability (static equilibrium ) ,find the member forces to be resisted ,and determine deflections . It requires that member configuration , approximate member sizes ,and elastic modulus ; linearity ; and curvature and plane sections . Various methods are used to complete the analysis .Final design . once a structural has been analyzed (by using geometry alone if the analysis is determinate , or geometry plus assumed member sizes and materials if indeterminate ), final design can proceed . Deflections and allowable stresses or ultimate strength must be checked against criteria provided either by the owner or by the governing building codes . Safety at working loads must be calculated . Several methods are available ,and the choice depends on the types of materials that will be used .Pure tension members are checked by dividing load by cross-section area .Local stresses at connections ,such as bolt holes or welds ,require special attention . Where axial tension is combined with bending moment ,the sum of stresses is compared to allowance levels . Allowable : stresses in compression members are dependent on the strength of material, elastic modulus ,member slenderness ,and length between bracing points . Stocky members are limited by materials strength ,while slender members are limited by elastic bucking .Design of beams can be checked by comparing a maximum bending stress to an allowable stress , which is generally controlled by the strength of the material, but may be limited if the compression side of the beam is not well braced against bucking .Design of beam-columns ,or compression members with bending moment ,mustconsider two items . First ,when a member is bowed due to an applied moment ,adding axial compression will cause the bow to increase .In effect ,the axial load has magnified the original moment .Second ,allowable stresses for columns and those for beams are often quite different .Members that are loaded perpendicular to their long axis, such as beams and beam-columns, also must carry shear. Shear stresses will occur in a direction to oppose the applied load and also at right angles to it to tie the various elements of the beam together. They are compared to an allowable shear stress. These procedures can also be used to design trusses, which are assemblies of tension and compression members. Lastly, deflections are checked against the project criteria using final member sizes.Once a satisfactory scheme has been analyzed and designed to be within project criteria, the information must be presented for fabrication and construction. This is commonly done through drawings, which indicate all basic dimensions, materials, member sizes, the anticipated loads used in design, and anticipated forces to be carried through connections.结构设计结构设计包含至少5个不同方面的工作:工程要求,材料,结构方案,分析和设计。

框架结构毕业设计外文文献翻译(外文原文中文翻译)

框架结构毕业设计外文文献翻译(外文原文中文翻译)

附录1:外文原文外文翻译附录2:外文翻译钢筋混凝土建筑在地震中的抗倒塌安全性研究(二):延性和非延性框架的对比分析(Abbie B. Liel1, Curt B. Haselton2, and Gregory G. Deierlein3)摘要:本文是两篇配套论文的第二篇,旨在探讨钢筋混凝土框架结构在地震中的抗倒塌安全性,并检验加利福尼亚州在20世纪70年代中期之前所建非延性框架结构建筑的可靠性。

基于对结构响应的非线性动态模拟进行概率评估,以此来计算对应于不同的地运动特性和结构类型时结构倒塌的危险。

评估的对象是一套不同高度的非延性钢筋混凝土框架结构原型,它们是根据1967年版《统一建筑规范》中的抗震规定设计的。

结果表明,当处于一个典型的加利福尼亚高震场地时,非延性钢筋混凝土框架结构发生倒塌的年平均频率范围为(5~14)×10-3,这比按现代规范设计的结果高出约40倍。

这些数据表明新规范对延性构造和能力设计要求是行之有效的,这使得在过去的30年中新建的钢筋混凝土建筑物的安全性得到明显改善。

通过对延性和非延性结构的安全性比较,有助于出台新的规章来评估和减轻现有的钢筋混凝土框架结构建筑物地震倒塌的危险。

关键词:倒塌;地震工程;结构可靠度;钢筋混凝土结构;建筑;商业;地震影响。

引言20世纪70年代中期以前加利福尼亚州建设的钢筋混凝土框架结构缺乏好的抗震设计理念(例如:加强柱子、钢筋延性构造),这使得它们很容易在地震中发生倒塌。

这些非延性钢筋混凝土框架结构在经历了加利福尼亚州1971年圣费尔南多大地震,1979年英皮里尔谷大地震,1987年惠蒂尔纳罗斯大地震,1994年北山大地震和世界上其他地方发生的无数地震之后,已经遭受了很严重的地震损害。

这些因素促使人们关注加利福尼亚州的近40000栋钢筋混凝土建筑,其中的一部分在未来地震中可能会发生倒塌而危害生命财产安全。

然而,我们缺乏足够的数据来衡量建筑的危险程度,因而无法确定是大量的建筑均存在这种危险,还是只有特定的建筑物才存在危险。

图书馆框架结构设计外文翻译六

图书馆框架结构设计外文翻译六

图书馆框架结构设计外文翻译六文档编制序号:[KK8UY-LL9IO69-TTO6M3-MTOL89-FTT688]南 京 理 工 大 学 紫 金 学 院毕业设计(论文)外文资料翻译系: 机械工程系专 业: 土木工程姓 名: 袁洲学 号: 0外文出处: Design of prestressed concrete structures附 件: 1.外文资料翻译译文;2.外文原文。

注:请将该封面与附件装订成册。

(用外文写)附件1:外文资料翻译译文8-2简支梁布局一个简单的预应力混凝土梁由两个危险截面控制:最大弯矩截面和端截面。

这两部分设计好之后,中间截面一定要单独检查,必要时其他部位也要单独调查。

最大弯矩截面在以下两种荷载阶段为控制情况,即传递时梁受最小弯矩MG 的初始阶段和最大设计弯矩MT时的工作荷载阶段。

而端截面则由抗剪强度、支承垫板、锚头间距和千斤顶净空所需要的面积来决定。

所有的中间截面是由一个或多个上述要求,根它们与上述两种危险截面的距离来控制。

对于后张构件的一种常见的布置方式是在最大弯矩截面采用诸如I形或T形的截面,而在接近梁端处逐渐过渡到简单的矩形截面。

这就是人们通常所说的后张构件的端块。

对于用长线法生产的先张构件,为了便于生产,全部只用一种等截面,其截面形状则可以为I形、双T形或空心的。

在第5 、6 和7章节中已经阐明了个别截面的设计,下面论述简支梁钢索的总布置。

梁的布置可以用变化混凝土和钢筋的办法来调整。

混凝土的截面在高度、宽度、形状和梁底面或者顶面的曲率方面都可以有变化。

而钢筋只在面积方面有所变化,不过在相对于混凝土重心轴线的位置方面却多半可以有变化。

通过调整这些变化因素,布置方案可能有许多组合,以适应不同的荷载情况。

这一点是与钢筋混凝土梁是完全不同的,在钢筋混凝土梁的通常布置中,不是一个统一的矩形截面便是一个统一的T形,而钢筋的位置总是布置得尽量靠底面纤维。

首先考虑先张梁,如图 8-7,这里最好采用直线钢索,因为它们在两个台座之间加力比较容易。

Spring框架-毕业论文外文文献翻译

Spring框架-毕业论文外文文献翻译

外文文献翻译SpringFrameworkSpring is an open source framework, and Spring was launched in 2003 as a lightweight Java development framework created by Rod Johnson.In a nutshell, Spring is a hierarchical, JavaSE/EEfull-stack (one-stop) lightweight open source framework.The powerful JavaBeans based configuration management using the Inversion of Control (IoC) principle makes application components faster and easier.1.facilitate decoupling and simplify developmentThrough the IoC container provided by Spring, we can control dependencies between objects by Spring, avoiding excessive program coupling caused by hard coding.With Spring, users do not have to write code for the bottom tier requirements of single instance schema classes, properties, file parsing, and so on, and can focus more on top tier applications.2.AOP programming supportThrough the Spring functionality provided by AOP, it is easy to implement face oriented programming, and many features that are not easily implemented with traditional OOP can be easily handled by AOP.3.declarative transaction supportIn Spring, we can extricate ourselves from tedious and tedious transaction management code and flexibly manage the transaction through declarative manner, so as to improve the efficiency and quality of development.4.convenience program testingAlmost all test work can be done in a non container dependent programming manner, and in Spring, testing is no longer expensive, but something to do.For example, Spring supports Junit4 and can easily test Spring programs by annotations.5.convenient integration of various excellent frameworkSpring does not exclude all kinds of excellent open source framework, on the contrary, Spring can reduce the difficulty of the use of Spring framework, provides a framework for a variety of excellent (such as Struts, Hibernate, Hessian, Quartz) directly support the.6.reduce the difficulty of using Java EE APISpring provides a thin layer of encapsulation for many difficult Java, EE, API (such as JDBC, JavaMail, remote calls, etc.), and the use of these Java EE API is greatly reduced through the simple package of Spring.7.Java source code is a classic example of learningSpring source code, clear structure, exquisite design originality, embodies the master of the Java design pattern and the flexible use of Java technology accomplishment.Spring framework source code is undoubtedly the best practice example of Java technology.If you want to quickly improve your Java skills and application development level in a short time, learning an.The role of MVC - Spring is integration, but not just integration, and the Spring framework can be seen as a framework for enterprise solution levels.The client sends a request, the server controller (implemented by DispatcherServlet) to complete the request forwarding, call a controller for mapping class HandlerMapping, the class is used to map requests to the corresponding processor to process the request.HandlerMapping will request is mapped to the corresponding processor Controller (equivalent to Action) in Spring if you write some processor components, the general implementation of the Controller interface in Controller, you can call Service or DAO to operate data from the DAO ModelAndView used to store the retrieved data, some data can also be stored in response to the view.If you want to return the result to the user, it also provides a view of ViewResolver component in Spring framework, the component labeled Controller returns according to, find the corresponding view, the response response back to the user.Each module (or component) that makes up the Spring framework can exist alone, or can be implemented in conjunction with one or more other modules.Each module has the following functions: 1, the core container: the core container provides the basic functionality of the Spring framework (Spring, Core).The main component of the core container is BeanFactory, which is implemented in factory mode.BeanFactory uses the control inversion (IOC) pattern to separate application configuration and dependency specifications from theactual application code.Spring框架Spring是一个开源框架, Spring是于2003 年兴起的一个轻量级的Java 开发框架, 由Rod Johnson创建。

(完整版)哈佛分析框架外文文献及翻译

(完整版)哈佛分析框架外文文献及翻译

经营分析与估值克雷沙·G.帕利普保罗·M.希利摘自书籍“Business Analysis and Valuation”第五版第一章节1.简介本章的目的是勾勒出一个全面的财务报表分析框架。

因为财务报表提供给公共企业经济活动最广泛使用的数据,投资者和其他利益相关者依靠财务报告评估计划企业和管理绩效率。

各种各样的问题可以通过财务状况及经营分析解决,如下面的示例所示:一位证券分析师可能会对问:“我的公司有多好?这家公司是否符合我的期望?如果没有,为什么不呢?鉴于我对公司当前和未来业绩的评估,该公司的股票价值是多少?”一位信贷员可能需要问:“这家公司贷款给这家公司有什么贷款?公司管理其流动性如何?公司的经营风险是什么?公司的融资和股利政策所产生的附加风险是什么?“一位管理顾问可能会问:“公司经营的行业结构是什么?该策略通过在工业各个企业追求的是什么?不同企业在行业中的相对表现是什么?”公司经理可能会问:“我的公司是正确的估值的投资者吗?是我们在通信程序中有足够的投资者来促进这一过程?”财务报表分析是一项有价值的活动,当管理者在一个公司的战略和各种体制因素完成后,他们不可能完全披露这些信息。

在这一设置中,外部分析师试图通过分析财务报表数据来创建“中端信息”,从而获得有价值的关于该公司目前业绩和未来前景的展望。

了解财务报表分析所做的贡献,这是很重要的理解在资本市场的运作,财务报告的作用,形成财务报表制度的力量。

因此,我们首先简要说明这些力量,然后我们讨论的步骤,分析师必须执行,以提取信息的财务报表,并提供有价值的预测。

2.从经营活动到财务报表企业管理者负责从公司的环境中获取物理和财务资源,并利用它们为公司的投资者创造价值。

当公司在资本成本的超额投资时,就创造了价值。

管理者制定经营战略,实现这一目标,并通过业务活动实施。

企业的经营活动受其经济环境和经营战略的影响。

经济环境包括企业的产业、投入和产出的市场,以及公司经营的规章制度。

毕业设计论文外文文献翻译计算机科学与技术微软VisualStudio中英文对照

毕业设计论文外文文献翻译计算机科学与技术微软VisualStudio中英文对照

外文文献翻译(2012届)学生姓名学号********专业班级计算机科学与技术08-5班指导教师微软Visual Studio1微软Visual StudioVisual Studio 是微软公司推出的开发环境,Visual Studio可以用来创建Windows平台下的Windows应用程序和网络应用程序,也可以用来创建网络服务、智能设备应用程序和Office 插件。

Visual Studio是一个来自微软的集成开发环境IDE(inteqrated development environment),它可以用来开发由微软视窗,视窗手机,Windows CE、.NET框架、.NET精简框架和微软的Silverlight支持的控制台和图形用户界面的应用程序以及Windows窗体应用程序,网站,Web应用程序和网络服务中的本地代码连同托管代码。

Visual Studio包含一个由智能感知和代码重构支持的代码编辑器。

集成的调试工作既作为一个源代码级调试器又可以作为一台机器级调试器。

其他内置工具包括一个窗体设计的GUI应用程序,网页设计师,类设计师,数据库架构设计师。

它有几乎各个层面的插件增强功能,包括增加对支持源代码控制系统(如Subversion和Visual SourceSafe)并添加新的工具集设计和可视化编辑器,如特定于域的语言或用于其他方面的软件开发生命周期的工具(例如Team Foundation Server的客户端:团队资源管理器)。

Visual Studio支持不同的编程语言的服务方式的语言,它允许代码编辑器和调试器(在不同程度上)支持几乎所有的编程语言,提供了一个语言特定服务的存在。

内置的语言中包括C/C + +中(通过Visual C++),(通过Visual ),C#中(通过Visual C#)和F#(作为Visual Studio 2010),为支持其他语言,如M,Python,和Ruby等,可通过安装单独的语言服务。

同济大学土木工程本科毕业设计-框架结构设计翻译(译文)

同济大学土木工程本科毕业设计-框架结构设计翻译(译文)
Ase

d0 4
0.9743 nt
2
这里, 是每英寸的螺栓数。 R3.1 ACI 318 附录 D 要求用于地震作用下的锚栓,能抵抗模拟的循环地震作用。 经验表明受到典型地震作用的钢筋混凝土结构, 其塑性铰区的裂缝宽度发展大大超出了 ACI 355.2 中的预期。
混凝土中后置式机械锚栓的 试验步骤
R6
R6.3 R6.3.1………………………………………………………………...…………………………….. 12
毕业设计(论文)报告纸 R7
R7.2……………………………………………………………...……………………………………....12 R7.2.1…………………...………………………………………………...……………………….. ..12 R7.3 R7.3.1……………………………………………...……………………...……………………….. .12 R7.3.2……………………………...………………………………..….………………………….... 12
R5
R5.1…………………………………………………………………...……………………………….... 7 R5.1.1………………...…………………………………..…...……..……………….……………..…7 R5.1.2………………...……………………………………...……..………………….……………….7 R5.1.3………………...……………………………………...……..………………….……………….7 R5.2 R5.2.2………………...……………………...……………………..…………………….…………….9 R5.2.3………………...……………………...……..…………………………………….…………….9 R5.2.3.1………………...……………………...…………………………………….…………….10 R5.2.3.4………………...…………………...……..……………………………….…………….10 R5.4……………………………………………………………………...……………………………....10 R5.5 R5.5.1………………...…………………………………...……..…………………… .…………….10 R5.5.3………………...…………………………………...……..…………………… .…………….10 R5.5.3.2………………...…………………………………...……………………….…………….12

框架结构外文文献

框架结构外文文献

框架结构外文文献标题:框架结构的研究综述摘要:框架结构是一种广泛应用于建筑工程中的结构设计模式,它能够提供良好的承载能力和抗震性能。

本文通过综述国内外的相关研究文献,总结了框架结构在建筑工程中的应用、设计方法和优化技术等方面的研究成果。

研究发现,随着计算机技术的发展,框架结构的设计方法和优化技术也得到了很大的改进和提升,利用数值模拟和优化算法可以实现更加精确和高效的框架结构设计。

但是,目前对于框架结构的材料使用、施工工艺以及环境友好性等方面的研究还较少,有待进一步深入研究和探索。

关键词:框架结构、设计方法、优化技术、建筑工程1.引言框架结构是一种常用的建筑结构模式,它具有良好的承载能力、刚度和抗震性能,广泛应用于各种建筑工程中。

框架结构的设计和优化是一个复杂的问题,涉及到结构力学、材料力学和计算机技术等多个领域。

本文通过对国内外相关研究文献的综述,总结了框架结构的应用、设计方法和优化技术等方面的研究成果,并提出未来研究的方向和建议。

2.框架结构的应用框架结构广泛应用于建筑工程中,包括住宅、办公楼、商业中心、桥梁等各类建筑物。

它可以通过组合不同形状的框架单元,实现不同尺度和功能的建筑设计。

框架结构在建筑工程中的应用研究主要集中在结构形态设计、材料选择和施工工艺等方面。

3.框架结构的设计方法框架结构的设计是一个复杂的过程,需要综合考虑结构形态、材料性能和施工工艺等因素。

传统的设计方法主要是基于经验公式和手工计算,存在设计效率低、精度不高的问题。

近年来,随着计算机技术的发展,基于数值模拟和优化算法的框架结构设计方法逐渐成为研究的热点。

数值模拟方法可以对框架结构进行力学分析和性能评估,优化算法可以实现结构的最优设计。

研究发现,利用数值模拟和优化算法可以得到更加精确和高效的框架结构设计。

4.框架结构的优化技术框架结构的优化是为了实现结构的最优设计和性能的最大化。

目前广泛应用的优化技术包括遗传算法、粒子群优化算法、模拟退火算法和人工神经网络等。

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附录1:外文原文附录2:外文翻译钢筋混凝土建筑在地震中的抗倒塌安全性研究(二):延性和非延性框架的对比分析(Abbie B. Liel1, Curt B. Haselton2, and Gregory G.Deierlein3)摘要:本文是两篇配套论文的第二篇,旨在探讨钢筋混凝土框架结构在地震中的抗倒塌安全性,并检验加利福尼亚州在20世纪70年代中期之前所建非延性框架结构建筑的可靠性。

基于对结构响应的非线性动态模拟进行概率评估,以此来计算对应于不同的地运动特性和结构类型时结构倒塌的危险。

评估的对象是一套不同高度的非延性钢筋混凝土框架结构原型,它们是根据1967年版《统一建筑规范》中的抗震规定设计的。

结果表明,当处于一个典型的加利福尼亚高震场地时,非延性钢筋混凝土框架结构发生倒塌的年平均频率范围为(5~14)×10-3,这比按现代规范设计的结果高出约40倍。

这些数据表明新规范对延性构造和能力设计要求是行之有效的,这使得在过去的30年中新建的钢筋混凝土建筑物的安全性得到明显改善。

通过对延性和非延性结构的安全性比较,有助于出台新的规章来评估和减轻现有的钢筋混凝土框架结构建筑物地震倒塌的危险。

关键词:倒塌;地震工程;结构可靠度;钢筋混凝土结构;建筑;商业;地震影响。

引言20世纪70年代中期以前加利福尼亚州建设的钢筋混凝土框架结构缺乏好的抗震设计理念(例如:加强柱子、钢筋延性构造),这使得它们很容易在地震中发生倒塌。

这些非延性钢筋混凝土框架结构在经历了加利福尼亚州1971年圣费尔南多大地震,1979年英皮里尔谷大地震,1987年惠蒂尔纳罗斯大地震,1994年北山大地震和世界上其他地方发生的无数地震之后,已经遭受了很严重的地震损害。

这些因素促使人们关注加利福尼亚州的近40000栋钢筋混凝土建筑,其中的一部分在未来地震中可能会发生倒塌而危害生命财产安全。

然而,我们缺乏足够的数据来衡量建筑的危险程度,因而无法确定是大量的建筑均存在这种危险,还是只有特定的建筑物才存在危险。

一栋建筑物发生倒塌的危险大小,不仅取决于其原设计采用的建筑规范中的规定,也取决于结构布置、施工质量、建筑位置和场地的地震特性。

除了需要准确评估倒塌的风险之外,选择合适的危险承受值和最低的安全标准也是需要考虑的问题。

在这方面,通过比较评估根据新老建筑规范设计出的建筑物,能帮我们找到一种评估手段来确定目前设计能够接受的风险水平。

20世纪70年代中期以来,随着对地震破坏和钢筋延性的深入了解,建筑规范中对于钢筋混凝土抗震设计和构造措施的要求发生了显著变化。

同老式非延性钢筋混凝土框架结构相比,现代规范要求在高地震地区的框架结构要进行各种能力设计来防止或延缓不利的破坏形式(如柱剪切破坏,梁柱节点破坏)。

虽然人们普遍同意对于建筑规范的这些修改是适当的,但还是缺少足够的数据以量化其对地震安全性的改善程度。

这项研究采用基于性能的地震工程方法,以评估地震引起非延性钢筋混凝土框架结构倒塌的可能性。

基于性能的地震工程提供了一个概率框架,利用非线性时程模拟将地面运动强度与结构响应和建筑性能联系起来。

对非延性钢筋混凝土框架结构的评估基于原型结构所做的测试,这套结构是根据1967年《统一建筑规范》设计的。

这些原型结构代表了1950年至1975年间在加州建造的普通钢筋混凝土框架结构。

通过对非延性混凝土框架结构原型的非线性动态分析可以预测倒塌的发生,而在结构倒塌过程中利用仿真模型能够捕获强度和刚度的变化特征。

抗倒塌性能评估的成果是一系列保障建筑安全的措施,并将地震中抗倒塌能力与地震灾害联系到一起。

我们将这些结果与另一篇配套论文中的关于延性钢筋混凝土框架结构的数据进行比较。

原型钢筋混凝土框架结构这些非延性钢筋混凝土框架结构原型考虑了结构高度的变化,结构布置和细部设计,能够覆盖加州旧钢筋混凝土框架结构建筑物设计和性能的的预期范围。

制作原型时,我们查阅了钢筋混凝土部件和框架的关键参数,这些参数是由哈兹尔顿等人通过分析和实验获得的。

本项研究共制作了26个非延性钢筋混凝土框架原型建筑物。

本文主要侧重于这些设计中的12个,高度从2层到12层变化,并包括具有可替换设计细节的周边和空间框架侧向抵抗系统。

原型建筑均设计为有着20厘米平面楼板系统和7.6米柱间距的办公楼房。

2层和4层建筑的平面尺寸为38.1m×53.3m,8层和12层建筑的平面尺寸为38.1m×38.1m。

建筑首层层高4.6m,其余层层高4.0m。

我们参考了20世纪60年代在加州建设的钢混建筑的原结构图,来为原型结构选择典型的结构部置和几何形状。

原型仅限于无填充墙的钢筋混凝土框架,并且在高度和平面上比较规则,没有出现明显的强度或刚度突变。

非延性钢混原型结构是按照1967年《统一建筑规范》中的最高地震烈度区(3区)设计的,那个时代加州的大部分都属于这个烈度区。

二维框架的结构设计是由所需的强度和刚度控制的,应满足重力和地震荷载组合的要求。

设计也符合所有相关的建筑规范要求,包括最大和最小配筋率和最大箍筋间距。

1967年《统一建筑规范》规定,如果采用了延性构造措施,可以适当地减小基底剪应力。

然而,本研究并没有进行这种折减,只考虑标准的细部构造。

表1总结了每个结构的设计细节,在Liel 和Deierlein处可以获得非延性钢混原型的完整资料。

有4个4层和12层的原型做了细部加强,这会在随后的文章里作介绍。

我们将非延性原型钢混框架结构的抗倒塌性能与配套论文中的延性原型钢混结构做了对比。

如表2总结,这些延性框架的设计依据了《国际建筑规范》(ICC 2003)、ASCE 7 (ASCE 2002),、和 ACI 318 (ACI 2005)中的规定,并符合所有相关规范中关于强度,刚度,承载能力和特殊框架构造的要求。

这些结构得益于自20世纪70年代以来钢筋混凝土抗震设计规范不断增加的条款,包括各种关于能力设计的规定(例如:强柱弱梁,节点抗剪承载力设计)和构造措施的改进(例如,在梁柱塑性铰区增加横向约束,提高对搭接的要求,闭合箍筋)。

这套延性钢混框架是按照在土壤类型为Sd类的典型高震洛杉矶场地设计的,它处在2003版IBC设计地图的过渡区域。

表1 原型延性和非延性框架的设计属性附注:a)1967年《统一建筑规范》(UBC)中设计基底剪切系数取值为C=0.05T(13)≤0.10。

对于抵抗力矩的框架T=0.1N,N是层数(ICBO 1967);b)现代建筑的设计基底系数根据设计场地的反应谱取值。

洛杉矶场地的设计反应谱SDS=1.0g,SD1=0.60g。

计算式采用的周期根据规范公式算得,是结构的高度(英尺),并且规定了计算周期的上限()(ASCE 2002);c)柱子的属性沿结构高度变化,此处列出的是首层柱子的属性;d)各构件横向钢筋的配置由所需的剪切强度确定。

每个位置至少有两根3号钢筋;e)延性钢筋混凝土框架横向钢筋的配置由所需的剪切强度确定。

所有的弯锚都有抗震构造,并使用4号钢筋(ACI 2005);f)梁属性沿结构的高度变化,此处列出的是第二层梁的属性;g)所设计结构的梁柱构造优于平均水平;h)所设计结构的节点构造由于平均水平。

表2 原型延性和非延性框架的建模参数附注:a)此处列出的是首层柱的参数;b)轴向荷载包括恒荷载和25%的活荷载;c)有效割线刚度为通过40%屈服强度时的割线刚度;d)滞后能量耗散的计算公式为;e)参数获得于对结构模型的特征值分析;f)所设计结构梁柱的构造优于平均水平;g)所设计结构的节点构造优于平均水平。

对比表1所示的结构,我们可以看出在过去四十年间钢筋混凝土框架抗震设计规范的变化。

尽管对设计基底剪力的方程进行了修改,但对于相同高度的延性和非延性钢混框架结构,计算的结果还是相当接近的,只有在计算最矮的结构时才有较大的偏差。

两组建筑物之间明显的差别是部件的设计和构造措施,特别是在数量、布局、和横向加固方面。

现代钢混框架结构受剪切能力设计规定的影响,对于箍筋间距有着更严格的限制,例如:在延性钢筋混凝土梁和柱中横向钢筋要加密2到4倍。

最小配箍率保证了柱子有足够的强度来延缓楼层机构的形成。

因此,在节点处柱强度与梁强度的比值延性钢筋混凝土框架结构平均比非延性钢筋混凝土框架结构高出约30%。

非延性钢混框架结构对于梁柱节点区域的设计或加固也没有特别规定,而延性钢混框架结构的柱子则要求规定的尺寸并添加横向钢筋,以满足节点剪力的需要。

为满足特殊框架结构对节点剪切强度的要求,通常增加柱子的尺寸,从而减小轴压比。

非线性仿真模型每个原型非延性钢混框架的非线性分析模型,都包括一个二维三开间的侧向抗力系统,如图1所示。

分析模型能够体现柱子、梁、梁柱节点材料的非线性和大尺寸效应(P-Δ效应),这对于模拟框架的倒塌时十分重要的。

我们用端部部分铰接的构件模拟梁、柱及其节点,这些铰被部分约束以模拟真实情况,类似于弹簧铰。

结构模型不包括任何非结构构件或支撑重力荷载的部件,它们都不属于横向支撑系统。

本模型是在OpenSees 中建造的,该软件具有强大的计算功能。

图 1. 钢筋混凝土框架结构分析模型示意图在另一篇配套论文中,用集中弹簧模拟非弹性的梁、柱、节点,它们是根据三线图和伊瓦拉等人的滞后原则理想化而来的。

根据一系列经验关系,我们对代表梁和柱构件的非线性弹簧特性进行了预测,这些关系将柱子的设计特征同建模参数联系起来,并与实验数据进行了校核。

用于改进经验关系的试验,包括大量非延性构造的钢筋混凝土柱。

预测的模型参数反映非延性和延性钢筋混凝土构件的弯矩-转角行为的差异。

正如配套论文中所说的,由于缺少足够的梁的数据,对于钢筋混凝土梁的模型参数的校核是建立在柱子在低轴压水平下被测试的基础上的。

图2(a)显示了延性及非延性柱(均为4层建筑)的单调骨干曲线的性质。

众所周知,最大塑性转角θcap,pl对预测倒塌的发生有重要影响,它是柱子约束钢筋和轴压水平的函数,延性钢筋混凝土柱比非延性钢筋混凝土柱大约大2.7倍。

延性钢筋混凝土柱还有更强的后期旋转能力(θpc),这决定了的柱子屈服后强度退化的速度。

图2(b)表明在一个典型的地震加载过程中,柱的强度和刚度不断下降。

起始曲线的减弱过程由弱化参数λ控制,这是一个耗能的过程。

在非延性柱中由于缺少足够的约束,并且轴压荷载更大,其耗能的能力要比延性柱小很多。

模型参数需要校准到预期的水平。

在分析时需计入重力荷载,并忽略轴向、弯曲、剪切变形之间的相互作用,而这些因素对高层建筑物的影响是十分明显的。

图 2. 用非弹性弹簧模拟位于4层框架结构首层中的钢筋混凝土柱,其特点是:(a)单调;(b)循环。

表2中为非延性和延性的原型钢筋混凝土柱的建模参数。

钢筋混凝土梁的属性也是类似的,它们在其他地方被列出。

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