Seismic Performance Evaluation Of Reticulated Shell Based On Three-Dimensional Multi-Modal Pushover Method

The reticulated shell is a common long-span spatial latticed structure consisting of an upper reticulated roof and a lower substructure.This structure is widely used in public infrastructures,such as lstadiums,airport terminals,etc.In recent years,strong earthquakes have occurred frequently all over the world,and the damage and social impact of earthquakes have been huge.China is also one of the countries with the most severe earthquake disasters in the world.As an important social public infrastructure,the reticulated shell is very important for the prediction of its safety performance and rapid damage assessment after the disaster.Based on the existing research,this paper proposes a three-dimensional pushover method suitable for reticulated shell,using this method to calculate the seismic response of reticulated shell,and verifying its feasibility and accuracy,while using this method the vulnerability of the reticulated shell was studied.The main work carried out has the following aspects:(1)Reticulated shell structure modeling and dominant mode identification:Using SAP2000 and ABAQUS software,the refined modeling of double-layer cylindrical reticulated shell and K8 single-layer spherical reticulated shell considering accumulated damage of materials has been completed.By calculating the average modal strain energy ratio of each vibration mode and using it as the basis for judging the mode shape contribution,the dominant mode shape of the reticulated shell is determined,and the distribution law of the dominant mode shape of the reticulated shell is analyzed.(2)Research on three-dimensional multi-modal pushover method based on dominant mode(DMPA): Based on the existing dominant mode of reticulated shell,a three-dimensional load distribution model is proposed.Through theoretical derivation,the equivalent nonlinear single-degree-of-freedom system of each dominant mode of the reticulated shell is established,and the equivalent single-degree-of-freedom system of each dominant mode is analyzed by pushover to determine the equivalent single-degree-of-freedom system Performance points,and obtain the seismic response results of the structure through the approximate combination method.The calculation results of this method are compared with the results of nonlinear dynamic analysis to verify the accuracy and rationality of the method.(3)Research on the vulnerability of reticulated shell based on the DMPA method: Using the DMPA method,the seismic requirements of the structure are calculated,and the vulnerability of the upper and lower structures are analyzed separately,and their own seismic vulnerability analysis functions are established.The fragility function of the reticulated shell is established by introducing the conditional correlation coefficient that characterizes the relevance of the upper and lower structures.Finally,the influence of the aspect ratio and the rise-span ratio on the vulnerability of the reticulated shell is analyzed.