毕业设计 某花园公寓楼设计与招投标文件编制英文翻译

毕业设计某花园公寓楼设计与招投标文件编制英文翻译毕业设计泛美花园公寓楼设计与招投标文件编制英文文献翻译外文资料:Spread footing foundationA spread footing (also known as footer or simply a footing) is an enlargement at the bottom of a column or bearing wall that spreads the applied structural loads over a sufficiently large soil area. Typically, each column and each bearing wall has its own spread footing, so each structure may include dozens of individual footings.Spread footings are by far the most common type of foundation, primarily because of their low cost and ease of construction. They are most often used in small-to medium-size structure on sites with moderate to good soil conditions.Spread footings may be built in different shapes and sizes to accommodate individual needs, as shown in Fig. 13.1. These include the following:(1)Square spread footings (or simply square footings) have plan dimensions of B×B. The depth from the ground surface to the bottom of the footings is D and the thickness is T. Square footings usually support a single centrally-located column;(2)Rectangular spread footings have plan dimensions of B×L, whereL is the longest dimension. These are useful when obstructions prevent construction of a square footing with a sufficiently large base area and when large moment loads are present;(3)Circular spread footings are round in plan view. These are most frequently used as foundations for light standards, flagpoles, and power transmission lines. If these foundations extend to a large depth (i.e., D/B greater than about 3), they may behave more like a deep rge cylindrical above ground surface storage tanks also will behave as a circular foundation. Although the walls may be supported on an annular-shaped continuous footing(ring footing) and the roof may be supported by columns founded on square footings, the contents of the tank will be distributed evenly across the tank floor;(4)Continuous spread footings (also known as wall footings or strip footings) are used to support bearing walls;(5)Combined footings are those that support more than one column. These are useful when columns are located too close together for each to have its own footing. Sometimes, its is necessary to build spread footings very close to a property line, another structure. Because such a footing cannot be centered beneath the column, the load is eccentric. This can cause the footing to rotate and thus produce undesirable moments and displacements in the column.One solution to this problem is to use a strap footing (also known as a cantilever footing), which consists of an eccentrically loaded footing under the exterior column connected to the first interior column using a grade beam. Thisarrangement, which is similar to a combined footing, provides the necessary moment in the exterior footing to counter the eccentric load. Sometimes grade beams connect all of the spread footings; provide a more rigid foundation system.Bored concrete piles and steel pilesBored concrete piles are concrete columns cast inside the soil in a hole. The hole is drilled with various types of drilling tools whose choice depends the kind of soil in question. Bored piles are especially useful for applications in which vibration caused by driving should be eliminated. Piles with diameters of 300 to 500mm, 10 to 30m long and with design loads of 200to 400KN are in use. Piles with diameters larger than 600mm are termed drilled piers. The bored piles have the following advantages:(1) they are installed by drilling, which is preferred in stiff clays,;and wherever adjacent buildings and the inside of structures are apt to be damaged by vibration produced by driving;(2) they may be installed in practically unlimited lengths;(3) since they do not displace the soil, they are not accompanied by heave， they can be spaced as close as 1.75d apart.However, compared to the driven piles, they have a limited bearing capacity unless they bear on a rock.. This limited bearing capacity is contingent to the fact that they produce no soil displacement and, consequently, the soil adjacent to the shaft and the below the base is not compacted. Moreover,they are frequently installed incorrectly and this circumstance impairs their reliability.The steel piles are steel columns driven into the ground. They are capable of withstanding hard driving thanks to their strength and to the fact that they displace only a small volume of soil, the latter property makes them suitable for driving through hard soils and to greatdepths.The steel piles with relatively thin walls penetrate the soil without setting up heavy vibrations which are detrimental to adjacent buildings. They can easily be spliced or cut off and this property is advantageous whenever their length varies considerably due to the irregularity of the surface, for example, in driving to a rock.. It is also this property that makes them well adapted to driving in a limited headroom, for they can be driven in short lengths and readily spliced by welding during the installation.On the other hand, steel piles are expensive, and their use is confined to cases in which their large bearing capacity can be exploited to the full, for example, when they are end-bearing on a rock. In addition, they are adapted to hard driving and depth over 15m, and provide excellent service under heavy lateral loads, as in marine structures, where their parts which protrude into the air double as columns.The durability of steel in the ground, which is sometimes a matterof dispute. No failure of steel piles driven into the ground, which can be attributed to corrosion, has been recorded, except in organic, acidand chemical plants. When steel piles are used for marine or river structures, their sections extending above the low water should be protected by concrete jackets. In waterfront structure, the protective coatings and/or cathodic protection systems are always recommended. The design of a foundationThe design of a foundation method depends on several factors which, in areas where no previous experience with foundations is available, cannot be determined without trial. As a rule, several solutions are possible.There are several factors involved in the choice of an appropriate type of foundation. ，Questions which we wish to answer is how to transmit the load of the superstructure to the subsoil, how to construct the chosen type of foundation and how to build it at a reasonable cost. The purpose of foundations is to transfer the required load safely to the subsoil; therefore, a foundation should be designed to perform this task without detrimental deformation of the superstructure or failure of the supporting soil or rock under the effect of static load, dynamic load, seepage forces, scour, etc.In choosing the method of foundation, the designer generally adopts the procedure of :(1) obtaining information concerning the type of the superstructure involved and the loads acting thereon;(2) procuring geological exploration;(3) investigating the engineering properties of the soil in questions;(4) studying the customary types of foundations in relation to the load or structure, sensitivity to settlement, case of construction and eliminating the unsuitable types;(5) designing the chosen type proceeding from detailed soil mechanics data and computations;(6) estimating the cost;(7) evaluating the time required for construction.Prestressing MethodsPrestressed members are often classified by how the steel isstressed and anchored to the concrete. The member is said to be pretensioned if the steel is positioned in the form and stressed before the concrete is cast. A member is said to be post-tensioned when the steel is stressed after the concrete has hardened to a specific design strength.Pretensioning is used primarily in precasting plants to mass-produce members whose size and weight are small enough to permit shipment to the site by truck. If pretensioning is carried out in the plant, the contractor is not required to supply equipment and trained personnel to prestress members in the field.In precast plants, members are commonly constructed on a long slab.These casting beds, which may be 400 to 500ft (122 to152 m) long, permit a number of members to be pretensioned simultaneously(Fig.11.3).Large abutments, positioned at each end of the casting bed,are constructed with fittings to stress and anchor the tendons.。