Structural Behavior of Post-Tensioned Concrete Beams with Predefined Camber and Accidental Deflection

While predefined cambering is widely implemented in prestressed concrete (PSC) girder bridges to counterbalance dead load deflections, the literature addressing its direct influence on structural behavior remains limited. Existing research focuses primarily on providing the required camber during fabrication and accidental deflections, with sparse attention dedicated to the interactive effects of diverse predefined initial profiles on structural performance. In this paper, an experimental investigation on the effect of predefined camber and accidental deflection on the structural behavior of both reinforced and prestressed rectangular concrete girders under four-point bending loading is presented. Fourteen large-scale beam specimens were tested, including eleven prestressed and three conventional reinforced concrete (RC) girders having concrete compressive strengths of 30, 40, and 80 MPa with predefined initial profiles ranging from −30 mm to +30 mm on key structural parameters, including cracking propagation, stiffness degradation, structural efficiency, displacement ductility, and total energy absorption. Test results have shown that all girders failed in a ductile manner via progressive cracking. It has been observed that positive predefined cambers could positively affect the performance of prestressed girders to a large extent, as the +30 mm predefined camber improved the ultimate load capacity by 19.3%.