抗震设计中一些具体问题的分析和讨论

根据多年建筑结构抗震设计实践和对抗震规范的理解,提出以下一些观点及设计建议:1)8度区层数少高度低的规则框架结构、框架抗震墙结构、抗震墙结构等建筑的抗震等级和抗震墙底部加强部位高度可以适当降低;2)少墙框架抗震墙结构设计时应同时考虑框架结构和框架剪力墙两种计算模型,框架-抗震墙结构计算模型的结构弹性层间位移角可仅满足规范对框架结构的限制要求,同时,框架抗震等级按纯框架结构确定;3)确定抗震墙厚度时,应综合运用规范规定的抗震墙构造最小高厚比限值和高层规程附录D稳定计算公式;4)抗震墙底部加强部位应该按不同的受力情况和墙肢剪跨比,设置不同的约束边缘构件,约束边缘构件长度宜根据相对受压区高度ξ确定更合理。

Analysis and Discussion on Some Issues in Seismic Design of RC Structure

Based on the practice of the seismic design and the understanding on the seismic design codes,the viewpoints and suggestions are developed.(1)For the regular frame,the frame-shear wall structure,the shear wall structure and etc,there are a few floors and are constructed in the earthquake fortification zone of 8 degree,the level of earthquake resistance and the height of the reinforced part at the bottom of the seismic structural wall can be reduced properly.(2) When design of seismic wall structure with few wall frame,two type of calculation models for the fram and frame-shear wall structure should be considered.The elastic structural displacement between two levels in the calculation model for the frame-seismic wall structure can only meet the limitation of the frame structure stipulated in the code.And as well the seismic class for the frame should be defined as of normal frame.(3) When deciding the thickness of the seismic wall,min.limitation ratio of thickness height for the seismic wall structure in the code and the calculation formula for the stability in the appendix D of the regulations on high-rise building should be referred to comprehensively.(4)Different confined boundary members be placed at the bottom of the seismic structural wall according to the bearing condition and the ratio between shear and span for the wall.The length of the members should be reasonably decided based on the height of the relative pressure area.