Analysis Of Force And Seismic Performance Of Unbonded Prestressed Concrete Frame Structure

The unbonded prestressed concrete frame structure combines the characteristics of prestressed structures and assembled structures with the advantages of small residual deformation after the earthquake and strong self-resetting ability.At present,the research on the force and seismic performance of the prestressed concrete frame structure is focused on the assembly nodes or components.It is not uncommon to combine the prestressed assembly nodes with the prefabricated integral frame structure.Based on the numerical simulation method and the experimental results,the force and the whole frame of seismic performance of the assembly node studied.The node modeling method and the initial rotation stiffness formula of the node are proposed.The factors influencing the stress and seismic performance of prestressed concrete frame are analyzed by comparison with the cast-in-place frame model.The main work of the paper is as follows:(1)Using the numerical simulation method to establish the model of unbonded prestressed concrete direct assembly node,the simulation results are compared with the test results to verify the rationality of the modeling.The anchorage length of the prestressed tendons and the initial prestressing force of the prestressed tendons on the stress and seismic performance of the joints were analyzed.(2)Employing the method of theoretical deduction,the calculation formula of the initial rotational stiffness of prestressed concrete frame joints is proposed.The finite element analysis software was used to establish the nodal model with different parameters.By applying the vertical load at the beam end,the bending moment curve of the nodes under different parameters was obtained.The slope of the elastic section of the curve is taken as the initial rotational stiffness value of the node and then was compared with the calculated value of the theoretical calculation formula to verify the applicability of the initial rotation stiffness formula.(3)Based on the existing experimental results,a framework model of prestressed concrete is analyzed.Moreover,the static and elastic analysis of the frame and the cast-in-place frame are carried out to analyze the similarities and differences between the two parts.The mechanical properties and failure mechanism of the prestressed concrete frame structure are discussed.The influence of prestressed reinforcement prestressed stress and prestressed tendon arrangement on the force and seismic performance of assembly frame was investigated by means of parameter analysis.