基于概率的圆形RC桥墩性能指标量化分析

为了实现桥梁结构基于性能抗震设计,需要给出RC桥墩各等级性能水平下墩顶侧移率限值的量化定义。将RC桥墩抗震性能水平按完好无损、轻微损伤、中等损伤和严重损伤等损伤状态划分为四个等级。建立了RC桥墩各等级性能水平下墩顶侧移率计算公式,基于搜集到的74个圆形RC桥墩拟静力试验结果,通过多元回归分析,得到计算公式中轴压比、剪跨比和配箍特征值的相应系数。考虑计算公式中认知不确定性,采用K-S方法,对各等级性能水平下墩顶侧移率概率分布模型进行分析,结果表明,在5%重要性水平下概率分布模型服从对数正态分布。

Quantitative Analysis of Performance Index for RC Bridge Circular Columns Based on Probabilistic Method

The quantified definition of performance levels of reinforced concrete (RC ) columns in terms of limit drift ratio is necessary for the implementation of the performance-based seismic design (PBSD) of bridge structures .Four seismic performance levels have been defined for RC columns ,i .e .almost integrity ,slight damage ,moderate damage ,serious damage .The empirical formulas of drift ratio at each performance levels have been developed as well .On the basis of ex-perimental test results of 74 circular flexure dominant RC columns ,the corresponding coefficient of aspect ratio ,axial-load ratio and reinforcement characteristic value in the empirical formula were determined by multiple regression analysis . Considering the epistemic uncertainty of the empirical formula ,the probability distributions of drift ratio were examined at different performance levels .It is suggested that they are reasonably lognormally distributed with K -S test at the 5%significance level .