nonprestressed

Nonprestressed refers to concrete elements that are not subjected to intentional precompression through prestressing tendons. In ordinary reinforced concrete, reinforcement consists of steel bars or wires placed in tension after the concrete has cured. The concrete carries compressive stresses, while the steel carries tensile stresses, and the composite section resists bending and shear without prestressing. Nonprestressed concrete is contrasted with prestressed concrete, where tendons are tensioned so that the member is placed in compression before loads are applied, reducing tensile cracking and allowing longer spans or lighter sections.

Construction and materials: Nonprestressed elements use normal concrete and reinforcement using ordinary reinforcing bars. The design focuses on concrete strength, reinforcement layout, bond between steel and concrete, and serviceability criteria such as crack widths and deflection. In practice, slabs, beams, columns, and foundations in buildings and infrastructure are frequently nonprestressed.

Performance and limitations: Without prestress, members rely on concrete's compressive strength and steel's tensile strength. They may exhibit wider cracks under service loads, greater deflections, and a lower ultimate bending capacity for a given cross-section compared with prestressed members. They are typically simpler to fabricate and inspect, with lower equipment and construction costs for many projects.

Terminology and use: The term nonprestressed is often used to distinguish ordinary reinforced concrete (ORC) from prestressed or post-tensioned systems. It remains common in codes and standards that treat reinforced concrete as the baseline, with prestressing considered a specialized enhancement.