Risk analysis of a medieval tower before and after strengthening
Risk analysis of a medieval tower before and after strengthening
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中世纪塔加固前后的风险分析
DOI：
10.1016/0167-4730(96)00007-0
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
I. Vanzi
中科院分区：
文献类型：
--
作者：
R. Giannini;T. Pagnoni;P. Pinto;I. Vanzi
这项分析的目的是评估帕维亚的弗拉卡罗铁塔在重力载荷(PF)下的失效概率，在最近的加固干预之前和之后。Pf及其对控制系统响应的随机变量分布参数的敏感度。提出了古代砾岩砌体结构材料特性的空间变异性和不确定性的概率模型。这既可以解释材料参数的连续变化，也可以解释由于局部降解材料和结构缺陷导致的强度急剧下降。采用三维非线性有限元模型对墙体进行了数值分析，考虑了墙体的局部受压和破裂。响应面(RS)方法的扩展版本与SORM算法相结合，允许有效地处理模型的数千个随机变量。RS的控制变量已经减少到几个主要的不确定源，而所有其他变量的影响，分组到适当的子集，已经以累积的方式考虑，并对适当计划的数值试验的结果进行统计处理。
The objective of this analysis has been the evaluation of the probability of failure under gravity load (Pf) of the Fraccaro tower in Pavia before and after a recent strengthening intervention. Both Pf, and its sensitivity to the parameters of the distributions of the random quantities controlling the system response have been evaluated. A probabilistic model of the spatial variability and of the uncertainties of the material properties typical of ancient conglomerate masonry constructions has been proposed. It accounts for both the continuous variability of material parameters and the drastic strength reductions due to localized areas of degraded material and construction defects. A 3-D nonlinear finite element model allowing for local crushing and fracturing of the masonry has been adopted for the numerical analyses. An extended version of the Response Surface (RS) method, coupled with a SORM algorithm, allowed for an efficient treatment of the several thousands of random variables of the model. The control variables of the RS have been reduced to a few major sources of uncertainty while the effects of all other variables, grouped in appropriate subsets, have been considered in a cumulative manner with a statistical treatment of the results of suitably planned numerical experiments.