Study On The Seismic Performance Of The Precast Concrete Frame System Using Metal Damper Connector

The research of the new technology of precast concrete(PC)frame structure connection and its mechanical properties has always been the focus of the scholars and researchers.It is a key scientific problem in this field to research and develop PC structure system with comprehensive high performance and easy industrialization development through innovative joint connection technology.In this paper,the research ideas and new progress of PC frame "wet" connection,"dry" connection and unbonded "post-tensioned" connection were analyzed,and proposes a new research idea of assembly structure connection technology: using energy dissipation devices as connectors between prefabricated components.According to the above ideas,the precast concrete frame system using metal damper connector(PCF-MDC)was developed.Technical solutions are given for three key technical problems of column-metal-beam joints in PCF-MDC system,including the selection of metal dampers,design of metal damper and development of connection scheme.In order to verify the feasibility of the technical scheme and the comprehensive performance of the PCF-MDC system,the performance test of the metal damper was carried out first,and then the seismic performance test of the PCF-MDC joint adopting the above technical scheme was carried out.The main research contents and conclusions are as follows:1.In Chapter 2,the technology scheme of the PCF-MDC joint is described in detail.Dog bone damper and double bending plate damper suitable for PCF-MDC system is proposed.The design goal of the metal damper is to achieve the yield of the metal damper prior to the prefabricated component.The design principle is that the yield bending moment of the metal damper should be lower than the flexural capacity of the beam section.A detachable connection scheme using steel channel and U-shaped anchorage components is proposed.2.In Chapter 3,the performance of dog bone and double curved plate damper is tested.The test results show that the double bending plate damper is subjected to in-plane bending failure,while the dog-bone damper is subject to bending and torsion failure due to insufficient out-of-plane stiffness.By changing the material distribution characteristics(geometric properties)of the cross-section,the double-curved plate damper can improve the out-of-plane stiffness and control its failure mode effectively.Double bending plate damper,better and more stable bearing capacity,and better safety reserve,can make full use of the plasticity of steel.3.In Chapter 4,seismic performance tests were carried out on "wet" PC joint(PCF specimen)with "equivalent cast-in-place" concept and PCF-MDC joints using dog bone damper(PCF-DB specimen)and double bending plate damper(PCF-DP specimen)in Chapter 3.The test results show that the bearing capacity of PCF-MDC joints reaches the original design value.PCF-DP specimen has better bearing capacity and safety reserve.The preset beam hinge energy dissipation mechanism composed of metal dampers in PCF-MDC is reasonable and effective,and its energy dissipation characteristics are better than PCF specimen.The connection scheme can reliably transfer the internal force between the metal damper and the prefabricated components.Through the research work in this paper,it is proved that the seismic performance of PCFMDC joint is better than that of equivalent "cast-in-place" precast concrete frame joint,and it has comprehensive high performance such as "concentrated damage" and detachable.At the same time,the new idea of "using energy dissipation devices as connectors between prefabricated components" is feasible and effective,which provides a new idea and direction for the research of assembly structure connection technology.