钢结构【英文】
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– Light weight, strong – Used extensively on roofs and floors
• Castellated beams – F14-7
Erection
• Usual process uses three crews
– Raising crew – lifts member into position and temp bolts it into position (safely) – OSHA regs – structural integrity – ability of structure to safely stand during erection
Structural Steel
– Camber and sweep
• Camber – looks like frown allows for beam to return to level position once load is applied • Sweep – curve in beam
Steel Construction
3 components
• 1) Advanced Planning
– Divisioning – dividing structure into units used to schedule fabrication and delivery
• Determined by order in which structure is erected • Joint effort between fabricator and erection manager
– Riveting – not used much today
Field Connections
• Fastening systems
– Welding
• All welders should be certified by American Welding Society • F 14-14 standard welding symbols • Welds must be tested & inspected for quality
• Safety regs - erection floor cannot be more than 8 floors above highest completed permanent floor, Not more than 4 floors of unfinished connections above highest permanently secured floor
• By size or by placement on structure • Want all material for a unit in one place
– Inspecting
• Welds, rust, warped or torqued
– Storing – store off ground, protect from dirt, grease, corrosion
– Shop drawings, steel type, built up or rolled section, connection method, camber
• 3) Delivery
Field Operations
• Receiving and unloading
– Sorting – shake out – id members with code
– Fitting crew – brings member into proper alignment and tightens enough bolts to hold it in place – Fastening crew – final connections
Lifting Equipment
Alignment of Steel
• Guys
– Cables used to align members – Do not overstress
• Erection of Steel Joists
– Require lateral bracing
• Cannot release joist from crane until braced
Safety
• Hard hats, gloves • Eye protection for welders, cutters, chipping ops • Harnesses if off ground level
– – – – And scaffolding Over 25’ – safety nets Tag lines on all hoisted beams to handle swing Surfaces of beams must be dry and suitable for walking
• Large members stored on truck until erection • Need a large enough storage area • Yarding – storing in a temp area and then moving to erection area
– Erecting
– Must check size and weight of members against plant capacity, transportation size, wt limits, erection equipment capacirication
– – – – Visual – quickest must be highly trained Destructive – used when questionable quality radiographic, ultrasonic provide image of weld magnetic particle, liquid penetrant inspection - show flaws
Structural Steel
• Types of Steel
– A36 carbon structural steel – most common – A572 High Strength – Low Alloy Structural Steel – A 588 Corrosion resistant High Strength – Low Alloy Structural Steel – Weathering steel – develops protective coating – no painting required
• Cranes, tower cranes • Small jobs may see F 14-9 ( old stuff)
Alignment of Steel
• Within tolerances of AISC Code of Standard of Practice
• Vertical or plumb error +/- 1 unit in 500 units of height • Outside columns cannot be more than 1” towards or 2” away from building line in 20 stories • Minimum clearance between members • Coping or blocking – notching beams to provide clearance when connecting beams to columns • Electrical and plumbing notches need to be designed
Field Operations
• Must be careful unloading steel
– Can damage surface coating, bend or torque members – Use double slings to avoid bending members – Must inspect for damage and conformance to shop drawings and tolerances – T14-1
Field Connections
• Fastening systems
– Bolting
• Two types of bolt systems
– Interference-body or interference-fit bolts » Oversized bolt driven into hole – holds bolt in place while tightened – Tension Control or tension set bolts » Bolt stem breaks when specified torque hit – In both cases need to make sure that bolts are tightened to specified torque – F14-11, 14-12
Structural Steel
– Standard Rolled Shapes
• F 14-2, T 14-2
– Built up members
• F14-3 • Used when common rolled shape is not available • Open web joists and joist girders, F14-5&6
• Castellated beams – F14-7
Erection
• Usual process uses three crews
– Raising crew – lifts member into position and temp bolts it into position (safely) – OSHA regs – structural integrity – ability of structure to safely stand during erection
Structural Steel
– Camber and sweep
• Camber – looks like frown allows for beam to return to level position once load is applied • Sweep – curve in beam
Steel Construction
3 components
• 1) Advanced Planning
– Divisioning – dividing structure into units used to schedule fabrication and delivery
• Determined by order in which structure is erected • Joint effort between fabricator and erection manager
– Riveting – not used much today
Field Connections
• Fastening systems
– Welding
• All welders should be certified by American Welding Society • F 14-14 standard welding symbols • Welds must be tested & inspected for quality
• Safety regs - erection floor cannot be more than 8 floors above highest completed permanent floor, Not more than 4 floors of unfinished connections above highest permanently secured floor
• By size or by placement on structure • Want all material for a unit in one place
– Inspecting
• Welds, rust, warped or torqued
– Storing – store off ground, protect from dirt, grease, corrosion
– Shop drawings, steel type, built up or rolled section, connection method, camber
• 3) Delivery
Field Operations
• Receiving and unloading
– Sorting – shake out – id members with code
– Fitting crew – brings member into proper alignment and tightens enough bolts to hold it in place – Fastening crew – final connections
Lifting Equipment
Alignment of Steel
• Guys
– Cables used to align members – Do not overstress
• Erection of Steel Joists
– Require lateral bracing
• Cannot release joist from crane until braced
Safety
• Hard hats, gloves • Eye protection for welders, cutters, chipping ops • Harnesses if off ground level
– – – – And scaffolding Over 25’ – safety nets Tag lines on all hoisted beams to handle swing Surfaces of beams must be dry and suitable for walking
• Large members stored on truck until erection • Need a large enough storage area • Yarding – storing in a temp area and then moving to erection area
– Erecting
– Must check size and weight of members against plant capacity, transportation size, wt limits, erection equipment capacirication
– – – – Visual – quickest must be highly trained Destructive – used when questionable quality radiographic, ultrasonic provide image of weld magnetic particle, liquid penetrant inspection - show flaws
Structural Steel
• Types of Steel
– A36 carbon structural steel – most common – A572 High Strength – Low Alloy Structural Steel – A 588 Corrosion resistant High Strength – Low Alloy Structural Steel – Weathering steel – develops protective coating – no painting required
• Cranes, tower cranes • Small jobs may see F 14-9 ( old stuff)
Alignment of Steel
• Within tolerances of AISC Code of Standard of Practice
• Vertical or plumb error +/- 1 unit in 500 units of height • Outside columns cannot be more than 1” towards or 2” away from building line in 20 stories • Minimum clearance between members • Coping or blocking – notching beams to provide clearance when connecting beams to columns • Electrical and plumbing notches need to be designed
Field Operations
• Must be careful unloading steel
– Can damage surface coating, bend or torque members – Use double slings to avoid bending members – Must inspect for damage and conformance to shop drawings and tolerances – T14-1
Field Connections
• Fastening systems
– Bolting
• Two types of bolt systems
– Interference-body or interference-fit bolts » Oversized bolt driven into hole – holds bolt in place while tightened – Tension Control or tension set bolts » Bolt stem breaks when specified torque hit – In both cases need to make sure that bolts are tightened to specified torque – F14-11, 14-12
Structural Steel
– Standard Rolled Shapes
• F 14-2, T 14-2
– Built up members
• F14-3 • Used when common rolled shape is not available • Open web joists and joist girders, F14-5&6