Study On The Mechanical Behavior Of New Precast Joints And Components With Steel End Connectors

Compared with the traditional cast-in-site structure,precast structure has many advantages such as high efficiency, good economic benefits, energy conservation and environmental protection. With the promotion of building industrialization, precast structure has become the effective way to realize industrialisation production. However, because of the poor connection between the components, the traditional precast structure has defects in integrity and seismic performance, and it’s not so suitable for this structure to build in earthquake protection region. Therefore, study on the mechanical behavior of the connection between components is of great significance to promote the development of precast structure. Based on the domestic and international research, this paper proposes a new rigid connection of precast stiffened concrete structure. And a series of experimental study and finite element analysis have been done on the precast frame joints and composite beams with the new connection. The main contents are as follows:① According to the parameters such as the height of the column, floor slab and reinforcement, six precast joints with the new steel end connectors were designed and made to test under low cyclic load. The seismic behaviour indexes, such as the load-displacement hysteretic curves, skeleton curves, ductility, energy dissipation and strength degeneration were analyzed. The working performance of the steel end connectors was also investigated. The results showed that: the tset specimens had good capacity and seismic behavior, and the steel end connectors worked well, so this new connection could be applied in practical engineering.② According to the parameters such as the failure patterns, lower reinforcement and shear span ratio, six precast composite beams with the new connection were also designed, including two bending beams and four shearing beams. The analysis of the test load-deflection curves, the flexural and shear bearing capacity was made to evaluate the mechanical behavior of the components and the working performance of the steel end connectors. The results showed that: the failure patterns of the bending beams were similar to the ordinary reinforced concrete beams, and the shearing beams failed in bending before the critical diagonal crack appeared, with a higher shear capacity than the flexural capacity. And there was almost no deformation beside the steel end connectors, so the own bearing capacity of the beams can be ensured.③ By using the FEA software ANSYS, numerical analysis on the mechanical behavior of these composite beams was conducted to compare with the test results. And the influence on the bearing capacity of the beams due to the length, height and width of the steel end connectors was studied.④ In accordance with the standards of different countries, comparison of the calculations of the flexural and shear bearing capacity was completed. On the basis of experimental study and finite element analysis, a suggested calculation method of the bearing capacity of these precast composite beams with the new steel end connectors was put forward.