Research On Shear Performance Of Full-scale Steel Reinforced Reactive Powder Concrete Beams

Reactive powder concrete(RPC),a kind of ultra-high performance concrete(UHPC),has been widely used in the fields of infrastructure such as bridges,railways,water conservancy,nuclear power and municipal construction since its emergence because its strength,toughness and durability are much higher than that of normal concrete.Considering the diversity of combining form of RPC and steel,many researchers try to excavate the engineering utilization value of RPC in the area of composite structure.Many studies show that steel reinforced RPC beams combined by different sections types can give full play to the advantages of the two materials.According to the current research situation,the research on the combination form of RPC and steel mainly focuses on the theoretical analysis of the material performance and the experimental study of the hetero-shaped cross-sectional beam components,which the application range is relatively limited.In the field of engineering applications,little shear performance analysis for full scale rectangular cross-section SRRPC beam was carried.In order to meet the urgent demand of the current structure for the shear capacity of the SRC beams,this paper comes up with a new type of highstrength high-performance combination beams—Steel Reinforced Reactive Powder Concrete Beams,and carries out a test study on its shear performance.Mainly completed the following work:(1)Six full-scale SRRPC beams with a length of 3500 mm and a section size of200mm×300mm were made to be carried out static load shear experiment,the effect of RPC strength,shear ratio and steel content on shear performance of SRRPC beam were mainly considered.The strain of measuring point was collected,the distribution and development of cracks in the shear span were observed,the deflection and the load values at key stages were recorded,and the development trend of the strain and deflection with the increase of load was described with charts.The experimental results display that this new kind of composite beam can take full advantage of the material strength of RPC and steel,steel fiber and steel improve the failure mode of specimen,and the setting of stirrup enhances the connection between RPC and steel and makes them work well together.(2)Based on one kind of finite element softwares,the shear test of SRRPC beam is simulated and calculated.The shear performance of the simulated specimen is match well with the test results.Using the same modeling method to carry out parameter expansion analysis of 32 SRRPC beams(divided into 5 groups),the effect of steel web thickness,RPC strength,shear span ratio,stirrup ratio,and steel flange thickness are mainly considered.(3)By comparing and analyzing the previous versions and the current versions of JGJ 138 and YB 9082 of two composite structure codes in China,and other scholars’ research result in the area of SRC structure,the application conditions and boundedness of each calculation model are expounded.Based on the algorithm of JGJ 138 and the test data of this paper,the proposed calculation model for the shear capacity of SRRPC beam under concentrated load is put forward.(4)According to the truss-arch model theory,the shear force transmission mechanism of SRRPC beam has been analyzed,and the theoretical calculation model of SRRPC beam shear capacity is came up with.Considering the softening effect of RPC in the truss model,the theoretical calculation formula is modified.After the modification,the shear capacity of SRRPC beams can be better estimated,which is of engineering reference value.