Seismic Fragility Analysis On Hybrid Structure Of Gymnasium Based On IDA

As a common school sports building,the gymnasium usually adopts the mixed structure with a frame structure at the upper part and a frame-bent structure at the lower part.The collaborative workability between the upper and the lower structures of gymnasium mixed structures is ignored in seismic design since the performance requirements of the frame structures are often taken as its design standard.Therefore,the seismic performance of gymnasium mixed structures is difficult to evaluate.In this paper,the seismic fragility analysis was conducted on the hybrid structure of gymnasiums based on IDA.The seismic performance of engineering structures in terms of statistical probability was evaluated quantitatively.Ground motion intensity measures and performance levels quantification was also discussed,which is the key science issue in the seismic fragility analysis based on IDA.The main research contents are summarized as follows:A typical rain playground project was taken as a research objective.Modal analysis was conducted using design software YJK and finite element analysis software ABAQUS,respectively.The rationality of the finite element model was verified by comparing the first three order vibration mode and period of analysis results of the two software.Period curves plotting were conducted based on the modal analysis results of ABAQUS.The dominant model of the structure was determined by combining the modal mass participation factor.Different ground motion intensity measures Se,3D*applied for the hybrid structure of gymnasiums considering the effect of period extension and synergistic working ability is proposed.The 10 remote field vibration records were selected based on the parametric procedure of IDA in ABAQUS.The correlation,validity,and adequacy of PGA and Sa（T1,ξ）suggested by the code,S*only considered the effect of period extension,and S123 which only considered the influence of high order mode were evaluated.The above research used maximum single column displacement angle as the structural damage index.The results show that the Se,3D* with full consideration of the period extension effect and synergistic workability can better evaluate the seismic performance of the hybrid structure.Performance levels of the hybrid structure of gymnasiums were divided based on the international standard and existing research results of the hybrid structure of gymnasiums damage model.The performance level method of structure is proposed based on the structural damage calculation method of material damage and considering cumulative damage effects.The seismic fragility was conducted by using PGA,Sa（T1，ξ）,S*,S123 and Se,3D*as ground motion intensity measures.The result shows that the structural performance leveling quantization method considering the damage accumulation effect proposed in this paper can obtain more reliable performance leveling quantization results.Compared with other ground motion intensity measures,Se,3D*has better safety and more conservative.