Study On The Bearing Mechanism Of PCSC Shear Connection Applied To The Assembled Composite Beam

Prefabricated and steel-concrete composite structures are two trends in the development of modern bridge construction.In this paper,based on teacher led the Ministry of Transport technology project "the overall/half range prefabricated steelconcrete composite beam bridge construction technology research"(2018-MSI-019),the group of prefabricated steel-concrete composite girder bridge PCSC shear connection structure to carry out the preliminary experimental research,theoretical analysis and numerical simulation,the main research content is as follows:(1)Based on the main parameters of whether the side baffle-concrete interface is debonded or not and the stripping rate of the successively poured concrete interface layer,12 shear connection specimens in 5 groups have been tested by Multi-stage load horizontal cyclic loading and monotone failure loading.the test shows that the interface layer of pavement specimens,there were stud fracture failure mode,the interface layer road.the processing concrete interface layer has appeared in a specimen of the basic fracture failure mode.(2)On the basis of experiments,the shear capacity,shear stiffness and shear-slip capacity of PCSC shear joint specimens were systematically studied.Compared with the existing codes and the conventional cast-in-place joints,the influence of the interface layer characteristics of post-perfusion concrete and precast concrete slabs on the antishear performance was studied.The results show that the ultimate bearing capacity of the joint structure is about 1.5 times of the calculated value.In the bearing capacity limit state,the shear stiffness of PCSC coupling structure is higher than that of conventional connectors.Under the multi-stage cyclic load,the stiffness of the specimens did not degrade.The void of concrete interfacial layer affects the failure mode and load slip rule of the specimen,but has no effect on the ultimate bearing capacity.(3)The simulation analysis of the push-out test is carried out with the finite element model,the modeling process is introduced in detail and the reliability of the model is verified;The stress of bolts and concrete in the specimen was analyzed.The influence of the side baffle on the ultimate bearing capacity of the joint structure is analyzed.(4)Based on the test data of a large number of stud connectors provided by references,the relationship between the influencing factors of failure mode and the bearing capacity was analyzed;a simplified mechanical model of PCSC shear joint structure is established,and the bearing mechanism of the side baffle is analyzed.Based on the experiment and numerical simulation,the bearing capacity calculation formula for PCSC shear joint structure is presented.