11/22/2017
Pre Cast Concrete (3)
Cast In Place Concrete (1)
• Mild reinforced concrete • Reinforcing Bar (rebar) ranges from #3 - #18 • Mild rebar ranges from #6 - #8 • Reinforcement in slabs ▫ Control cracking due to shrinkage • Reinforcement in beams, columns etc ▫ Control crack due to tensile forces
• Typical Buildings with CMU construction ▫ Correctional Facilities
▫ Office Buildings ▫ Retail Buildings ▫ Educational Facilities
Pre Stressed Concrete
Pre Cast Concrete (4)
Pre Tensioned
• Tilt Up Construction with Pre Cast Concrete ▫ Concrete elements are formed on a concrete slab ▫ Temporary casting surface near building footprint • After concrete is cured: ▫ Elements tilted to place ▫ Horizontal to Vertical with crane ▫ Braced into position
Post Tensioned
Typically Pre Cast
Bonded
Unbonded
Reinforcement tensioned by hydraulic jacks that push against the concrete
Reinforcement allowed to create a friction based bond with concrete
Reinforcement coated with grease to prevent friction based bond with concrete
Steel reinforcement is tensioned before the concrete is placed
Advantages
Purposes
Clear Spans Thinner slabs Slender members
Parking garages
Pre Cast Concrete (5)
Flexibility in column layout Span lengths Ramp configurations Slab-On-Ground and Mat Foundations
Lower overall building height floor-to-floor Significant reduction in building weight Reduced foundation load Advantage in seismic areas Slabs and Beams can be continuous Structurally efficient
• SigmaStud®
Expansive soils with low bearing capacity Reduce problems with cracking Reduce differential settlement
▫ Alternative to CMU ▫ Load bearing steel stud
• Advantages:
Geometry challenging bridges Complex curves
▫ Light weight ▫ Increase in load capacity ▫ Compatible with code changes ▫ Accelerated construction schedule
Variable super elevation Significant grade change
Long Span bridges
Without intermediate supports Minimizes impact on environment
• Complete Wall System: • StiffWall® (Shear Wall) • Wall Bridging • Jambs • Openings • Rigid Connectors
Rock and Soil Anchors
Tunneling and slope stabilization Tie backs for excavation
Crack free concrete Water tanks
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