Abstract

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Title:: Experiment on Flexural Behaviors of Prestressed Reactive Powder Concrete Box Girders

Author(s):: FANG Zhi; LIU Ming; ZHENG Hui; College of Civil Engineering, Hunan University

Keywords:: reactive powder concrete; box girder; flexural behavior; shear-lag effect; crack; deformation

Abstract:: In order to study the mechanical behavior of prestressed reactive powder concrete (RPC) box girders, the flexural behavior tests of two prestressed RPC box girders were carried out. The force characteristic of RPC box girders and the influence of transverse prestressing force to its flexural performance were studied. The results show that the prestressed RPC box girders display a good deformation capacity, with a maximal deflection of 1/50 of its span. The crack width and the shorttime stiffness of the RPC box girders can be calculated according to the formula in Technical Specification for Fiber Reinforced Concrete Structures (CECS 38:2004), with a coefficient of 0.4 and 0.2 considering influence from steel fiber, respectively. The transverse prestressing force in the top plate of RPC box girders has little influence on the flexural bearing capacity, but the force can make a more uniform strain distribution of the compressive concrete so as to reduce the shearlag effect and increase the ductility of the specimen. By applying a transverse prestressing force of 2.95 MPa (only 3.1% of the RPC prism compressive strength of 94 MPa) at the top plate, the effective distribution width of box girder increases by 10%, and ductility index of specimen increases by 3%. The calculated formula to evaluate the cracking moment and the ultimate moment of a prestressed RPC box girders is proposed and verified by the experimental results.