Dynamic Response Analysis Of Long-period Structure Under Long-period Ground Motion

The lack of records of long-period ground motion causes grate uncertainty of DRS number at long-period segment. However, high-rise buildings are usually seriously destroyed under long-period earthquake due to its long structure period. According to “Code for seismic design of buildings” of China, as to long-period structure, seismic influence coefficient declines rapidly at long-period spectrum, which causes weaker structural action effects under horizontal earthquake. Under the consideration of safety, the horizontal seismic shear of each floor and the whole structure should be above a maximum number.In research, a structure with concrete and shear wall structure and another office whose structure reinforced concrete core wall with its colunm is made of pipe and concrete and its beam is made of steel in the six degrees area.Thinking or not thinking the consideration of seismic shear coefficient,then choose the seismic wives adjusted to the response spectrum and long period seismic waves.At last,make analysis of the sructure undering rare earthquake response. As follows,I will show the main findings;(1) Making analysis of the waves when changing them to response spectrum. To sum up,the acceleration response of the larger epicentral distance seismic waves’ spectral response in declining section is much greater than the normal seismic waves’ response spectrum and the design spectrum.(2) Making nonlinear analysis of the shear wall and office structure undering the seismic wives adjusted to the response spectrum and two long period seismic waves. Comparing the response analysis results of the elastic-plastic of the shear wall structure and office structure.Both can meet the displacement angle and plasticity performance requirements in the seismic wives adjusted to the response spectrum. They work well under long-period seismic waves L1364. But under the long-period seismic waves L1197-2 both of their displacement angle can’t meet the regulator requirements.We can conclude that a large component of the long-period seismic waves on the structure displacement.The shear weight ratio adjustment of long-period structure plastic displacement response improvement is also very limited.It is recommended for high-rise buildings, not only adjust the shear weight ratio, but also improve the structure of lateral stiffness in order to avoid long-period ground motions structural damage.(3) The seismic waves’ acceleration may adjust by EPAor by PGA. Acceleration response of response spectrum adjusted by EPA is greater than adjusted by PGA, but both spectral response acceleration is proportional response. The development level of beams shear plastic hinge and the extent of damage undering the seismic whose acceleration adjusted by EPA is slightly heavier than adjusted by PGA.(4) Comparing the Chinese and Ameriacn response spectrum.Concluding that national response spectrum declines slowlier than American spectrum in the long-period segment; the decline slope of the national seismic response spectrum is 0.9 while the decline slope of the American seismic response spectrum is 2.