Prestressing is a broad engineering technique where steel reinforcement is tensioned to compress the concrete, counteracting the tensile stresses it will face in service. Concrete is strong in compression but weak in tension. By prestressing it, the entire cross-section remains in compression under load, preventing cracks. This category includes both pretensioning and post-tensioning methods.
The precast plant will prestress the bridge girders to ensure they can handle the highway traffic loads without deflecting.
Prestressing allows for much longer spans and thinner structural profiles than conventional rebar reinforcement.
Related terms
Pretension
To stretch steel reinforcement cables before the concrete is poured around them.
Post-tension
To apply tension to steel cables inside concrete after the concrete has hardened.
Tendon
The steel strand assembly in post-tensioned concrete that is pulled tight to precompress the member.
Compressive strength
The crushing load concrete can carry per unit area, the main property specified and tested for concrete.