直接基于位移的PPC框架性能水准量化及设计位移可靠度分析

在按照我国现行规范设计的16榀PPC框架的Pushover抗震性能分析的基础上, 对PPC框架性能水准的量化指标及DDBD法中设计位移的可靠度问题进行了研究。提出了结构基本完好、生命安全和防止倒塌三个性能水准的划分定义和以裂缝宽度、承载力指标等作为各性能水准的量化参考指标, 并以量化参考指标对应的层间位移角作为其最终的量化指标。同时, 将量化指标层间位移角做为抗力, 预期风险水平地震下层间位移角反应作为效应, 提出了一种以我国现行规范隐含的各性能水准可靠度为基础的考虑可靠度问题的简化方法。在某一性能水准下, DDBD法最终计算所得可靠度值β可视为一个与现行规范隐含可靠度值相对大小的量, 极大避免了计算用变异系数取值差异带来的误差, 且能满足同一性能水准的不同设计要求。

QUANTIFIACTION OF PERFORMANCE LEVELS AND RELIABILITY ANALYSIS OF DESIGN DISPLACEMENT IN DDBD OF PPC FRAMES

Based on the analysis of the seismic performance of 16 partially prestressed concrete (PPC) frame structures designed according to China current codes, the quantitative index of PPC frame performance levels and the reliability of a design displacement in Direct Displacement-Based Design (DDBD) had been analyzed. After three performance levels of basic integrity, life safety and collapse prevention defined, crack width, bearing capacity had been suggested as a quantitative reference index and the corresponding interstory drift ratio as a final quantitative index. At the same time, taking the interstory drift ratio corresponding to a quantitative index as resistances and corresponding to expected earthquakes as effects, a simplified method had been put forward, in which reliability can be taken into account in DDBD and associated to the reliability level of current codes. In this method, the error arose from the coefficient of variation can be avoid greatly and different requirements can be satisfied under an identical performance level.