| The frame-core tube structure is valued for its outstanding seismic performance in numerous structural forms.A large number of earthquake damages indicate that the frame-core tube structure can form multiple seismic lines under strong earthquakes.Studying the seismic response of this type of structure is of great significance for ensuring the safety of life and property.Seventeen-story steel frame-fiber reinforced concrete core tube structure model is established,and the seismic performance target of the structure is proposed.The elastoplastic time-history analysis of the structure is carried out under the action of strong earthquakes.The vulnerability of the structure is evaluated based on the results of incremental dynamic analysis.And factors affecting structural vulnerability are researched.(1)Using SAP2000 to build structural models.The basic dynamic characteristic parameters of the structure are obtained by modal analysis.Next,the structure is analyzed under the rare earthquake analysis and the extraordinary earthquake.Under rare earthquakes,Interlaminar displacement angle average value of steel frame-fiber reinforced concrete core tube structure is 14% better than ordinary concrete steel frame-core tube structure.Base shear force average is 18% higher than ordinary concrete steel frame-core tube structure The rare earthquake results show that the use of fiber reinforced concrete in the reinforcement zone at the bottom of the core can improve the seismic performance of the structure.Under extraordinary earthquake,in steel frame-fiber reinforced concrete core tube structure most of the frame beams have entered the elastoplastic state before the frame column of the emerge yield.At the same time,the core reinforcement area at the bottom of the core tube is subjected to most horizontal earthquake effect.The results of extraordinary earthquakes show that the structure meets the seismic design idea of strong columns and weak beams.And the structure has a certain anti-collapse reserve capacity.(2)based on Incremental dynamic analysis(IDA)method.The subject first proposes the failure criterion and divides the five limit states.The subject selects multiple seismic waves suitable for site conditions for analysis.Draw three quantile curves.Find the mean of the performance points of the three quantile curves and establish the five performance points of the final IDA curve cluster.Obtain the failure probability curve of the structure in each state.The IDA curve can reflect the entire process of the structure from elastic state to collapse.The analysis based on the IDA curve cluster shows that the average value of the maximum interlayer displacement angle of the structure is 1/107 when it is close to the collapse limit state;The seismic intensity Sa corresponding to the 50% failure probability when approaching the collapse performance point has 0.82g;All the above indicators indicate that the structure has good collapse resistance.Among the five performance states,the dispersion is greater in life safety limit state and near the collapse limit state.Anti-collapse reserve coefficient of structure under rare earthquakes CMR is 3.76.The results show that the structure has a certain safety reserve under the action of large earthquakes.Under the analysis of vulnerability factors,The subject selects the influencing factors of shear wall thickness and column axial compression ratio.The results show that reasonable shear wall thickness and small column axial compression ratio can improve the seismic vulnerability of the structure. |
