[摘要]性能设计不仅是提高结构的安全度,更应该是针对地震的偶发性和震害对社会及经济的危害以及小震、中震、大震重现周期和作用效应的巨大差别,预先选取在不同水准地震作用下结构的抗震性能目标,按期望的目标值,确定相应的延性和构造措施。通过静力或动力非线性分析,掌握结构和构件及节点在大震作用下的全过程反应,判别弹塑性层间位移角是否超过规定的限值,构件和节点是否具有足够的延性等等,实现一系列预期的性能目标。文中推荐美国ASCE41-06构件塑性变形的可接受准则,提出了高层建筑的基本安全性能目标为中震作用下的梁端、大震作用下的剪力墙底部加强区应出现弯曲塑性铰,目标值LS,以耗散大部分的地震能量,降低底部剪力。使用PERFORM-3D,通过工程实例,详细解释了上述性能目标的实现过程。
[关键词] 性能设计,抗震性能目标, PERFORM-3D
Abstract: For performance-based design of tall buildings, it should not be only for enhancing the safety objective of buildings, but the selection of an acceptable target building performance level in accordance with earthquake hazard level. Depending on the selected building objective, the ductility is required for components such beam, column and wall. The responses of the building are obtained by the static or dynamic non-linear analysis procedures to achieve the selected target building performance level. As Basic Safety Objective, it may be reasonable for the tall buildings to yield at the ends of beams and to select Life Safety level at the BSE-1 earthquake hazard level, Collapse Prevention level at the BSE-2 earthquake level. For the base end of wall, the target performance level of Immediate Occupancy may be selected for the BSE-1 earthquake hazard level, Life Safety level for the BSE-2 earthquake hazard level. In doing so, most of the energy of seismic wave would be dissipated by rotation of the plastic hinges at the ends of the beams. The base shear would be reduced as the degradation of stiffness of the structure during earthquake. As an example, one engineering project is illustrated, which is analyzed by using PERFORM-3D.
Keywords: performance-based design, target building performance level, PERFORM-3D