Research On Seismic Performance Of Multi-story Cantilever Steel Structure

In order to pursue a strong visual impact on architectural shape and a spacious and facile interior space,the cantilever structure is widely used in various types of high-rise buildings.Force concentration on root and obvious torsion effect is the features of cantilever structure.Which will do unfavorable effect on the structural seismic performance.Therefore,a multi-floor steel cantilevered structure was selected,and focusing on the seismic performance of vertical and horizontal key component-the cross-slab main cantilever truss,a quasi-static test and finite element analysis were conducted and some advice about seismic design and long-term application of cantilever structure was provided.The following five sections and conclusions are covered in this dissertation.(1)Based on the similarity theory,the prototype structure was simplified and scaled into a 1:10 test model.The similarity relationship between test model and prototype structure was verified by calculation.(2)The static loading test was carried out on the test model,and the results show that test model has no plasticity development under 1.35 times design load,therefore,the prototype structure has a superior design safety reserve.(3)The quasi-static test was carried out on the test model,and seismic performance including energy dissipation capacity,ductility,and failure mode of the main truss were analyzed.The results indicated that there was pinch phenomenon in the loaddisplacement hysteresis loops and test model had a certain ductility.The final failure mode was fracture failure of the partial sub-truss thin-walled members and plastic failure of the roots of main cantilever trusses.(4)A finite element analysis was performed on the test model.The finite element results agreed well with the monotonic test load displacement curves and load strain curves.The shape of the finite element load displacement hysteresis curves were fusiform,and the overall plasticity of the finite element model was fully developed.The comparison with the test model showed that the prevention of continuous rupture of the sub-truss members in a multilayer large cantilever structure is beneficial to the structural seismic performance.(5)The dynamic time history analysis and static response spectrum analysis were performed to calculate the maximum displacement response of prototype structure under the rare earthquakes.Based on the displacement similarity relationship,it was convinced that the test model loading had exceeded the design regulated rare earthquake and the seismic performance of the prototype structure was evaluated to meet the design regulations.