Experimental Study of Prestressed Composite Beams

TLDR

Prestressing steel structures have recently gained attention, yet experimental verification of prestressed composite beams—especially under negative bending moments—is lacking. The study experimentally investigates the behavior of prestressed composite steel‑concrete beams. Two beams, one under positive and one under negative bending moments, were tested with load‑deflection curves and strain measurements of concrete, steel, and prestressing bars recorded. Predicted internal forces and deformations from equilibrium and compatibility equations closely matched the measured data.

Abstract

The concept of prestressing steel structures has only recently been widely considered, despite a long and successful history of prestressing concrete members. Several analytical studies of prestressed composite beams were reported in the literature, but much of that work was not experimentally verified. In particular, no test results were found on prestressed composite beams subjected to negative bending moment. This paper examines experimentally the behavior of prestressed, composite steel‐concrete beams. Two beams were tested, one subjected to positive bending moment and the other to negative bending moment. The load was plotted against the deflection, and the strains in the concrete, steel beam, and prestressing bars. The values predicted with the equations of internal force equilibrium and compatibility between the deformations of the bars and the composite beam were found to correlate well with the measured data.