Experimental Study On Axial Tensile Of RPC-FST Influenced By Wall Thickness

In order to improve the steel tube concrete strength and the tensile and flexural member ductility,the actual bridge structure using the C60 micro expansion steel fiber concrete filled steel tube,such as Ganhaizi bridge of concrete filled steel tubular truss beam and lattice column.Related engineering practice and the research results show that if can improve the tensile strength and ductility of the concrete filled steel tube,will further improve the combination of the concrete filled steel tube structure,especially the cracking performance,flexural strength and flexural rigidity.As the basis of the engineering application research,this article will research on performance of steel tube RPC tensile test,the main work and achievements are as follows:(1)Based on common building materials,designing the proportion of high tensile ductility of RPC.(2)Under Sichuan Ganhaizi bridge tension chord,designed and produced of 15 of the axial tensile specimen directly,and to improve the axial test method and test device,including clamp,cover plate and the measuring method of displacement.Test parameters include steel tube wall thickness(1.5 mm,2.0 mm,2.5 mm,3.0 mm and 3.5 mm).(3)By analyzing the phenomenon of steel tube RPC tensile test,and compare the different parameters on the specimen failure pattern,the load-deformation curve,working performance and failure principle of the RPC filled steel tube is studied.(4)The wall thickness of steel tube RPC specimens with different steel direct axial tension load-deformation(strain)the whole process of curve,and the initial slope,initial crack strain and load,peak load and strain,ultimate strain and eigenvalue analysis and comparison.And through the noise,cracks and steel fiber was uprooted and strain analysis of specimen failure mechanism,through RPC poisson's ratio,crack strain changes(compare with RPC axial tensile specimen)analysis of steel tube and the combination of RPC.(5)On the basis of the experimental research results,combined with domestic and foreign relevant formula of bearing capacity of steel tube concrete in tension,the steel tube RPC tensile bearing capacity of the composite section and the method for calculating the initial stiffness,verify whether the practical algorithm calculation accuracy is more accurate,simple calculation steps.