Research On Numerical Analysis Method And Dynamic Behavior Of Structures With Precast RC Diaphragms

Precast building has been favored by the industry with its own high quality,economy and environmentally-friendly architectural features in recent years.The research and application of un-topped precast RC diaphragm is an important direction for the development of prefabricated buildings.The joints at the slab connection are often in the state of combined bending,shearing,and axial force under horizontal earthquake action,the mechanical properties of joints at the slab directly affect the in-plane stiffness and integrity of the diaphragm;the in-plane deformation makes the dynamic behavior of the entire building structure significantly different from that of the ordinary cast-in-place structure.Based on the experimental studies of fully assembled RC diaphragm joint connection,the research for numerical analysis method of the un-topped RC diaphragm and the dynamic behavior of the entire building structure are very important.In this paper,based on the tests of un-topped precast RC diaphragm hairpin slab joint connections,un-topped precast RC diaphragm hairpin-cover plate hybrid slab joint connections and in-plane mechanical performance of un-topped precast RC diaphragm,the ABAQUS finite element analysis program is used to research on numerical analysis method and dynamic behavior of un-topped precast RC diaphragm building structures.The main contents are as follows:(1)Develop 2D discretized connection element models for slab joint connections.The ABAQUS finite element analysis program was used to establish a 2D discretized connection element model for the slab joint connection for structural dynamic pushover analysis and dynamic elastic time history analysis.The slab joint connection test results were used to modify the model to precisely reflect the actual force condition of the connectors between the slab joints.This will provide basic conditions for the dynamic analysis of new types of diaphragms and multiple high-rise building structure with new types of diaphragms.(2)Establish a 2D finite element model for new type of diaphragms.Using the modeling method of the research content(1),a 2D numerical analysis model of a precast concrete floor was established to analyze its in-plane mechanical properties and compared with the experimental results to verify the accuracy of the modeling method.(3)A high-rise building model with an un-topped precast RC diaphragm was established to analyze its dynamic characteristics and seismic response laws and compared with that of the ordinary cast-in-place building structure.The results show that the influence of in-plane deformation of the diaphragm on the structure cycle,lateral displacement,base shear and acceleration of the floor can't be ignored.On this basis,proposals for a new type of multiple high-rise building seismic design method are built.The numerical simulation analysis method used in this paper can provide references for numerical analysis of subsequent models;the research results can provide basic suggestions for the research and application of un-topped precast RC diaphragms and building structures with such kinds of diaphragms.