Analysis On Dynamic Damage Reason And Bearing Capacity For Single-layer Latticed Shells Considering Buckling Of The Member

Currently, the dynamic analysis method for the single layer-latticed shells is not perfect. In order to achieve the actual dynamic responses and damage reasons of single layer-latticed shells subjected to seismic excitations, it is necessary to study the calculating model and analysis method for single layer-latticed shells in depth. On this account, study on the causes of dynamic damage and bearing capacities of single layer-latticed shells is carried on in this paper after exiting research works are reviewed.(1) Based on the mechanical characters of the member of single layer-latticed shells, member calculating model which can exactly simulate both the developing process of deformations and ultimate bearing capacity of element with plastic hinge at the end is presented by our research team.(2) Time history analysis of single layer reticulated dome, single layer single layer latticed cylindrical shell and single layer ellipse parabolic latticed shells with the member calculating model in this paper are made, and the results of which indicate that all of the changes of mechanical performances of the structural members, the buckle-straighten processes of the members, the form-disappear processes of the plastic hinges, and consequent complex change processes of structural bearing capacity can be reflected well by the member calculating model. Simulation of the full-range dynamic response processes of single layer latticed shells subjected to seismic excitations is realized by the method proposed in this paper. Causes of dynamic damages of single layer-latticed shells subjected to seismic excitations are studied. The dynamic damage of single layer reticulated dome is caused by buckling members which weaken the structural bearing capacity; the dynamic damage of single layer latticed cylindrical shell is caused by concentrative plastic hinges at the ends of some members which make some parts of the structure turn to mechanisms; the dynamic damage of single layer ellipse parabolic latticed shell is caused by combined actions of the two causes mentioned above. Dynamic response characters of single layer reticulated domes and single layer latticed cylindrical shells subjected to seismic excitations are further studied by incremental dynamic analysis method. (3) The initial geometrical imperfection of single-layer latticed shells is described by normal random variable, and the ultimate bearing capacities of imperfect structures are calculated based on the member calculating model. The expression of structural ultimate bearing capacity based on the reliability is presented, and the error expression is deduced. Numerical analysis indicated that subjected to critical load some members get buckled which leads to the decrease of the structural bearing capacity. The structural bearing capacity will be overestimated without considering buckling of the member.