钢筋混凝土框架结构基于位移的抗震设计方法研究

DISPLACEMENT-BASED SEISMIC DESIGN METHOD OF RC FRAMES

根据钢筋混凝土框架结构的特点,将其性能划分为使用良好、人身安全和防止倒塌三个水平,并用层间位移角限值予以量化;用作用倒三角形水平分布荷载的等截面悬臂柱的侧移曲线作为框架结构的初始侧移模式。在此基础上,将多自由度体系转化为等效单自由度体系,导出了相应的等效参数。结构的目标位移根据其性能水平确定,并用假定的侧移模式给予修正。在等效线性化的前提下,由等效位移用弹性位移反应谱求出等效周期,然后对结构构件进行刚度设计和承载力设计。最后用静力弹塑性分析方法对结构进行分析,校核结构的侧移形状与初始侧移模式是否一致,并用推覆至相应性能水平时的侧移曲线作为修正后的侧移曲线重新计算。算例分析表明,本文方法简单实用,便于操作,而且能够控制结构在不同强度水准地震作用下的性能。

According to the characteristics of RC frames, its seismic performance is divided into three levels： serviceabihty, life-safety, and collapse protection. The three levels are quantified with storey drift ratios. Applying the inverted triangular distribution of lateral force to the cantilever column of identical section, and the displaced shape of the column is regarded as the initial mode of lateral displacement. The multi-degree-of-freedom system is transformed into an effective single-degree-of-freedom system, and the corresponding equivalent parameters are derived. The target displacement is determined according to the corresponding performance level, and the lateral displacement curve is modified by the assumed lateral displacement mode. Based on equivalent linearization, the equivalent period is determined by using the elastic displacement response spectra, and then the structural members are designed. The buildings are analyzed by using a static elasto-plastic analysis method, if the ealculated significantly different from drift curve is the initial assumed shape, then take the pushover drift curve as the modifying drift shape and ealcuate again. It is demonstrated the method is accurate enough to be eomployed in building evaluation and design.