Numerical Models And Collapse Resistance Design Method Of Single-Layer Reticulated Shells Under Earthquake Excitation

Single layer latticed shell, which is a main structural type of spatial structures, has the characteristics and advantages of both member structure and shell structure, and it is widely used in our country. Presently, rigid connection and general beam element of finite element analysis software are usually used to simulate the structural joints and members in seismic analysis of single layer latticed shell. By those calculation models, the stiffness change of joints, the damage process of joints and the uneven plastic developing of members under earthquake excitation cannot be simulated, those factors will lead to the overestimation of bearing capacity of structure. Besides, a reasonable and feasible seismic collapse resistance design method of single layer latticed shell is deficient at present. To solve above-mentioned problems, based on exiting research work, some studies are carried out with numerical simulation as follows.(1)By numerical simulation of loading process of welded hollow spherical joint under earthquake excitation, the dynamic mechanical behavior characteristics of welded hollow spherical joint is studied. By parametric analysis, the relationship between the mechanical behavior of welded hollow spherical joint and size of joint, material strength and size of member are studied. Based on regression analysis, the mechanical calculation model for welded hollow spherical joint is established, which can simulate the repeated loading-unloading processes under earthquake excitation.(2)The mechanical behavior characteristics of structural members are summarized, the commonly used member models are enumerated, and the mechanical performance changes of cantilever beams based on different member models are comparative studied. Based on parameter analysis, the optimal quantity of fiber is determined when simulating structural member. Example analysis demonstrates that fiber model can fully simulate the uneven plastic developing of member, which has significant effect on the dynamic bearing capacity of single layer latticed shell.(3)A collapse criterion of single layer latticed shells based on displacement response is established. Based on the numerical calculation model of single layer latticed shell, the seismic collapse resistance performance of single layer latticed shells is studied by CMR analysis. the relationship between CMR and structure collapse probability is studied and a effective seismic collapse resistance design method of single layer latticed Shells is proposed based on CMR.