Prestressed concrete

Prestressed concrete is concrete with deliberately induced internal compression that counteracts tensile stresses from applied loads. It allows slender structural members to span farther and control cracking better than ordinary reinforced concrete.

Pre-tensioned concrete: Prestressed concrete in which tendons are tensioned before concrete is cast and transfer force to it after hardening. It creates prestress by releasing tendons held against external abutments.
Concrete: A composite construction material made from cement, water, and aggregates that hardens into a stone-like mass. Prestressing works by exploiting concrete's strong resistance to compression.
Prestressed concrete bridge: A bridge whose concrete members are compressed by tensioned steel tendons. Bridge girders use prestressing to span gaps with controlled cracking and deflection.
Eugène Freyssinet: A French engineer who pioneered practical prestressed concrete structures in the early twentieth century. His work established high-strength steel and deliberate prestressing as a viable system.
Steel-reinforced concrete: Concrete strengthened with embedded steel bars that carry tension after cracking. Ordinary reinforcement responds to tension from loads instead of balancing it with initial compression.
Post-tensioned concrete: Prestressed concrete in which tendons are tensioned after the concrete has hardened. It introduces compression by stressing tendons anchored to the hardened member.
Reinforced concrete: Concrete containing embedded reinforcement that carries tensile forces the concrete handles poorly. It resists tension through bonded reinforcement rather than deliberately compressing the member beforehand.
Post-tensioned slab: A concrete floor or roof slab compressed by tendons tensioned after casting. Post-tensioning permits thinner slabs and longer column-free floor spans.
Philosophy of prestressed concrete: Eugène Freyssinet's 1933 account of the principles and practice of prestressed concrete. It set out the reasoning behind using prestress to control concrete cracking and deformation.
Unbonded post-tensioning: Post-tensioning in which tendons are sheathed and do not bond continuously to surrounding concrete. Its tendons transfer force chiefly through end anchorages, unlike bonded systems.

Linked from 13 pages