Seismic Performance Study Of CLT Structure Based On Angle Bracket Connection Properties

In recent years,CLT heavy timber structure has been used in residential buildings,office buildings,gymnasiums and other building types because it can be used in multi-storey and high-rise buildings.Because of its green,environmental protection,sustainability and other characteristics,it has become a new choice to replace reinforced concrete buildings.At present,the research on CLT structure by domestic and foreign scholars is in the preliminary stage,and there is no relevant national standard to explain the design criteria of CLT structure.In this paper,starting from the CLT connection,the impact of mechanical properties of the connection on the seismic performance of the CLT structure is explored,so as to promote the development and application of the CLT structure and the green and sustainable development of the building industry.Based on no relevant research to explore the influence of the fastener number on the performance of angle bracket connections,Firstly through the loading test of Angle-bracket connections with the number of fasteners of 6,9,12,15 and 18,the influence of the number of fasteners on their mechanical properties,such as initial stiffness,yield displacement,yield strength and ductility ratio,was explored.Then the characteristic value of experience was compared with the theoretical value of the calculation model in the existing timber design codes and literatures,and the accuracy of the existing calculation model was analyzed.Based on the capacity-based design approach,three-dimensional numerical models of CLT were designed and analysed to explore the influence of Angle-bracket connections on the structural behavior factor q of CLT,and the main conclusions are as follows:(1)The initial stiffness,ductility ratio,yield load,maximum load,ultimate load and the corresponding displacement of CLT Angle-bracket connections all increase with the growth of the number of fasteners.(2)The theoretical values of connection carrying capacity obtained by EC5,B&U and ON models are conservative compared with the experimental values,while the ETA model overestimates the actual carrying capacity of connections with more fasteners.(3)For Angle-bracket connections with the same number of fasteners,the behavior factor q of CLT structure increases with the increase of the number of floor levels.For the same number of storey,the behavior factor q increases with the increase of the number of fasteners.The main innovations of this paper are as follows: The influence of the number of fasteners on the mechanical properties of the connections is explored by changing the number of fasteners of Angle-bracket connections.Based on the experience data and the capacity-based design approach,a three-dimensional numerical models of CLT were designed and established to explore the influence of mechanical properties of connections on the behavior factor q of CLT structure,so as to provide reference suggestions for the future seismic design of CLT structures.