Bending behaviour experiment of a prestressed concrete beam with metal bellows

Abstract

ABSTRACT In this paper, grouting compactness and load forms are taken as control conditions, and the bending behaviour of 8 PCBs (prestressed concrete beams) with metal bellows of different grouting compactness is experimentally examined. The strain and deflection of the prestressed beams are measured, and the failure process and failure modes are investigated under the action of different load forms. The rebar strain, bending bearing capacity and bending stiffness of the PCBs are explored, and a comparative analysis is conducted. The results show that the average strain is linearly distributed along the beam height for all PCBs. The load versus span deflection curve and rebar strain curve of the specimens show that the grouting compactness has little effect on the early stage of beam cracking, but the effect becomes increasingly obvious after the beam cracks. Under different load forms, when the grouting compactness of the PCB increases, the crack distribution becomes more concentrated, the spacing narrows, and the ductility decreases. The load-bearing capacity of the PCB with 100% grouting compactness can be improved by more than 30% compared with that of the prestressed beam with 0% grouting compactness of the metal bellows.