Study On Mechanical Property Of PBL Connectors For Timber-Concrete Composite Beams

The timber-concrete composite structure is a new type of structure based on timber-structure and concrete structure. The timber beam and concrete slab with different types of connection, timber in tension and concretein compression, can give full play to the optimal properties of two kinds of materials. In recent years, this type of structure is very popular in western countries, has become one of the frontiers and hotspots in this field. The composite structure of low energy consumption, low emission, light quality, has been widely used in Europe and the United states. Compared to the traditional timber, timber-concrete composite beams flexural stiffness and flexural capacity are improved.In the composite structure, the shear connectors at the interface of different materials are the important factors that influence connection. Therefore, the timber-concrete composite beams of the shear connectors are designed to design a combination of beams in an important link. In order to study the mechanical behavior of the shear connectors of timber concrete composite beams, the experimental study on the PBL shear connectors with better mechanical properties was carried out. Through the design of the thickness of the plate, the opening rate, the layout of the opening, to carry out the research of parameters. Static load test and finite element analysis were carried out on the 7 groups of 21 timber-concrete composite beams PBL connections, and the failure mechanism and mechanical properties of PBL connectors were discussed.This will be part of PBL shear test results and the composite structure of the joints shear strength calculation formula were compared, to provide reference for timber-concrete composite structure design and engineering application. At the same time, the push out specimen was analyzed by static simulation analysis by using ABAQUS finite element software, establishing finite element 1/4 model to simulate the push out test, PBL shear connectors of shear bearing capacity is obtained and extract of timber and concrete amount of relative slip, analyzed the PBL connector shear bearing capacity of the main influencing factors. The test results show that the perforated plate thickness increases, the stiffness is large, so its carrying capacity is bigger, at the same time, slip corresponding to the ultimate load will be smaller. When the other conditions remain unchanged, open hole are arranged in such a way to connect the bearing force is very small, but slip on its influence, generally, in the stress direction of a straight line, holes and more concentrated, slippage smaller. The opening rate shows that the number of holes increases, the number of holes increases, so long as the opening rate increases, the stiffness decreases, can increase the amount of slip, and decrease the bearing capacity. Finally, the finite element analysis results and the experimental data are compared.The stiffness values of the two are consistent, but the former is larger than the latter.