The Dynamic Characteristics Of Single Layer Reticulated Domes Under Severe Earthquakes

Currently, the research of the reticulated domes under dead load has obtained a series of results. However, the research of these structures under dynamical actions is still very insufficient. Most in the last few years, the failure mechanism problem of the reticulated domes under strong earthquake is noticed by the researchers increasingly.The failure may be caused by dynamic instability or strength failure or the result of the two causes.Because of the complexity of the reticulated domes, the huge quantity of poles and nodes, it's finite element model is complex. The model is reasonable or not, determines the calculation accuracy of the analysis. In this paper, by studying the composing characteristics and using APDL program, a reasonable finite element model of K8 single layer reticulated dome is set up, which can achieve perfect accuracy without too much time.Using the subspace iteration, dynamical characteristics of dome under the influence of geometrical rigidity are studied.At the same time, by parameter analysis, the influence of different of ratio of rise-span, span, division number and loads on dynamical characteristics of dome are discussed.In this paper, both the material nonlinear and the geometric nonlinear are considered. At this time, the theory of adding no longer applys, so can't get the biggest responses like elastic time-history method by adding the seismic response and the static response. The author think: a method by using PSTRES command to and the dead load then carrying out the time-history responses is more reasonable.Using APDL program, the seismic responses of single layer reticulated dome under the horizontal, vertical and combinations of vertical and horizontal earthquake actions are carried out. A detailed discussion is carried out on elstic-plastic seismic performanceof the domes, the study reveals that there must be a certain plastic development process before the failure appears. In fact, the failure of reticulated domes is caused by incessant interactive actions of the plastic development and deformation. And domes with less rise-span ratios present apparent characteristic of dynamic instability. The suggested values of the earthquake action coefficient of K8 reticulated domes are given. Also, the influence of the ratio of rise-span to seismic performance of the dome is investigated.