Study Of Dynamic Characteristic And Seismic Response For Precast RC Diaphragm Structure

In recent years,due to the high efficiency,good quality,short construction period,fast construction pace and environmental protection,the prefabricated building has become the future development direction and rational choice of the construction industry.When the castin-place floor and the assembled monolithic building structure are seismically designed,the rigid floor is often assumed to calculate the displacement and internal force of the building structure.For the new fully assembled RC floor,due to its limited in-plane stiffness,and under the horizontal load,the in-plane deformation will occur,then the rigid diaphragm is difficult to achieve.Therefore,it is very important to carry out research on the seismic performance of the fully assembled RC floor structure.In this paper,the building structure with distributed connection of the new fully assembled RC floor is taken as the research object.The numerical analysis method is used to study and discuss the dynamic characteristics and seismic response law of the structure,so as to study and apply the system in the future.Provide a theoretical basis.The main contents are as follows:(1)Based on the equivalent beam model theory,considering the assumption of the unbalanced tensile and compressive stiffness of distributed mechanical joints and the influence of frame side beams on the in-plane stiffness,the calculation of the in-plane stiffness of the distributed fully-connected RC floor is derived,and the feasibility of the method were verified by experiments.(2)The dynamic characteristics of tall building structures were studied.The finite element analysis program is used to establish the equivalent model of the new fully assembled RC floor building structure and the finite element analysis model of the traditional cast-in-place building structure of the same size and arrangement,and analyze the vibration mode and periodicity of the structure and compare them;The period of the building structure adopting the new fully assembled RC floor is larger than the period of the cast-in-place building structure;compared with the cast-in-place structure,when the seismic design of the new building structure is required,the number of vibration modes needs to be increased,that is,the high-order vibration needs to be considered.Type of influence.(3)Seismic response analysis of multi-tall building structures was carried out.The numerical analysis model of the whole building structure is established,and the dynamic elastic time history analysis is carried out;Under the action of horizontal earthquake,the in-plane deformation of the new fully assembled RC floor is more obvious,and the deformation effect in the plane of the floor is more obvious in the middle of the structure,the bottom and top layers are small;Due to the in-plane deformation of the new building cover,the internal force distribution of each lateral anti-side force structure under horizontal earthquakes has changed significantly compared with the cast-in-situ structure,and the shear wall structure bears the horizontal seismic shear force is reduced,and the horizontal seismic load of the frame part is increased;The floor acceleration of the new fully assembled floor structure is magnified to varying degrees,and the floor acceleration amplification factor of the different floor and side structure of the same floor exists larger difference.It is recommended to consider this difference when determining the horizontal design load of the floor,the vibration model of the “serialparallel multi-mass system” spatial structure considering the actual stiffness of the floor is used to analyze and design the structure.(4)Carry out unilateral analysis of monotonous napping of high-rise building structures.The lateral vibration mode load is applied and the push-over analysis based on the target displacement control method is carried out to study the structural performance and plastic hinge development and yield mechanism of the new fully assembled RC floor structure;Under the rare earthquake,the adoption Compared with the cast-in-situ structure,the building structure of the new fully assembled RC floor cover reduces the shearing force of the base and increases the seismic action;the displacement angle between the layers satisfies the elastoplastic interlayer displacement angle limit specified in the specification,so that the structure satisfies the the requirement that “the large earthquake does not fall”;the plastic hinge mainly appears in the middle of the structure,which is a weak link and should be paid attention to.In this paper,the research results of the seismic performance of building structures using distributed joints of new fully assembled RC floor and it is of great theoretical and practical significance to improve the seismic design method of the fully assembled building structure,solve the basic problems in the seismic design of the fully assembled building structural system,and innovate the structural system of the full dry RC floor.