A Shear Lag Analysis For Large-span Reactive Powder Concrete Box Girder

The RPC simple supported box girder uses a new material RPC to replace the traditional concrete. The new material have excellent performance in the mechanical properties and durability, which could significantly reduce the bridge weight and improve the spanning capacity. The present research is lack of the shear lag effect of the large span thin-walled box girder, so this paper uses the energy variational and finite element method to analyze the shear lag effects of the RPC simple supported box girders. The main analysis of the shear lag effect and the main conclusions are as follows:(1)Design48meters span RPC simply supported box girder and calculate it’s shear lag coefficient by the energy variational and finite element method. Establish the solid element and shell element bridge finite model in separately by ANSYS program to simulate the bridge shear lag effect when subject to concentrated load. Compare results of the two methods,provide the common shear lag distribution rule of the section.Also proved the validity of the two methods.(2)To analyze the influence of the different stress condition to the RPC bridge shear lag, taking various working conditions and the longitudinal prestressing force into account. By establish the bridge model with solid prestressed reinforcement,provide the common laws for the RPC bridge shear lag effects under these specified conditions. The results shows that the prestressing force have little influence on the distribution of shear lag in the mid-span section,however have more influence in the section near the support.(3)To analyze the influence of the different structure forms to the RPC bridge shear lag, considering differents factors including the width-span ratio, width-thickness ratio, the length of flange plate cantilever, the location of diaphragm plates, the structure of seam,the composite structure,and so on.Analysis are conducted by the ANSYS model to analyze the all these factors influence to the shear lag effect in the RPC simply-supported box girder.The variation rules of the shear lag effect of each parameter are presented in this paper,and main factors also be found.The measurements to decrease the shear lag coefficient of RPC simply-supported box girder are proposed.