Nonlinear Dynamic Elasto-plastic Time History Analysis Of Underwater Irregular Space Netty Steel Structure

Along with reform and opening-up policy of our country and booming dev elopment of the whole national economy, space structures growing up strongly.More and more majestic buildings standing in large and medium-sized cities, formed a regional landmark building and embodied the advantage of spatial stru cture. It can make people feeling modern civilization, at the same time also ref lect the building science and technology of our country has entered a new era that can compete with the international strength.But now the elasto-plastic analysis of the structure is mostly designed for high-rise building, there are relatively few studies for the research of underwater irregular space structure. The elasto-plastic time history analysis method was conducted to the underwater irregular space netty steel structure under the severe earthquake.According to the results, it has some significance and reference value for seismic performance research of this structure and considering the influence of the water under the severe earthquake. The specific content is as follows:(1) Introduce characteristics and concepts of space steel structure. then seismic analysis theory, the research history and present situation is expounded.(2) This thesis introduces the theoretical basis of the dynamic elasto-plastic time-history analysis, dynamic equilibrium equation and the related numerical algorithm; Expounds the method of selecting seismic wave according to the target response spectrum.(3) Using SAP2000 to establish the elasto-plastic finite element model. The seismic wave input motion included 2 earthquake records and 1 artificial wave by means of target response spectrum selection, including 12 loading cases based on three-dimensional import. The results show that the whole rigidity characteristic is fine, and under severe earthquake the maximum displacement is much less than the limit value. A few plastic hinges are formed, and mainly distributed in the center circle which is relatively weak, and less structural element yield. The results indicate that the design of the irregular space netty steel structure achieves the earthquake performance objectives and has ideal seismic behavior.(4) Considering the damping effect of water under seismic response of the structure, compare the result of models which have different damping ratios under severe earthquake, it is concluded that the dynamic analysis of underwater structure should consider the influence of the water damping; Then comparing the Housner model with added mass model, it concluded that water sloshing can make some damping effects for structure under horizontal function.