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31.
采用可靠度分析的蒙特卡罗法 ,建立了加筋土边坡稳定极限状态方程 ,对其可靠度进行了分析 ,并结合工程事例 ,讨论了土性参数的均值和变异系数对可靠度指标的不同影响 ,指出可靠指标度量加筋土边坡稳定性更合理。 相似文献
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Probabilistic loss assessment of light-frame wood construction subjected to combined seismic and snow loads 总被引:2,自引:0,他引:2
In some areas, e.g., mountainous areas in the western United States, both seismic and snow loads are significant. Limited research has been conducted to investigate the seismic risk of light-frame wood construction in those areas considering the combined loads, particularly the snow accumulation. An object-oriented framework of the risk assessment for light-frame wood construction subjected to combined seismic and snow hazards is proposed in this paper. A typical one-story light-frame wood residential building is selected to demonstrate the proposed framework. Economic losses of the building due to the combined hazards are evaluated using the proposed framework. It is found that in areas with significant snow accumulation, the snow load has significant effects on the seismic risk assessment for light-frame wood construction. 相似文献
35.
针对非确定性过程,引入集合卡尔曼滤波(EnKF)理论,视岩土变形体为一个随机动态系统,将位移观测值作为系统的输出,用集合卡尔曼滤波模型来描述系统的状态;进一步耦合数值分析方法实现岩土力学参数的随机动态估计,在有效地获得待估参数的同时还给出估计值的不确定性。通过数值算例表明,集合卡尔曼滤波可以有效地对含噪声的量测数据进行处理,能够跟踪岩土力学行为的动态变化。对比于常用最优化算法,集合卡尔曼滤波同时给出反演结果和先验知识的后验分布,显示出更好的实时性和可靠性。 相似文献
36.
数值模拟联合算法及其在润扬大桥可靠度评估中的应用 总被引:3,自引:0,他引:3
为了定量研究大跨桥梁在外界随机因素作用下的结构安全性,实现在线状态的可靠度评估,利用可靠度的随机有限元法对润扬大桥悬索桥在正常运营和损伤等多种工况下的结构可靠度进行了数值模拟和可靠度评估。分析中采用蒙特卡罗重要抽样法和中心复合响应面法的联合算法作为数值模拟的基本工具,介绍了联合算法的具体实现途径、随机变量的参数定义并对大跨桥梁基于可靠度指标的评估准则进行了讨论。得到了多个随机变量的概率灵敏度、主要失效模式所对应的可靠度指标及其相应的状态等级。算例分析结果表明,基于随机有限元的可靠度分析方法可以较好地描述大跨桥梁的非线性特征,联合算法的应用提高了可靠度分析的效率和精度,其结果为润扬大桥悬索桥的状态评估和健康监测提供了参考。 相似文献
37.
A reliability analysis method is proposed in this paper through a combination of the advantages of the response surface method (RSM), finite element method (FEM), first-order reliability method (FORM) and the importance sampling updating method. The method is especially applicable for the reliability evaluation of complex structures of which the limit state surfaces are not known explicitly. After the accuracy and efficiency of the method are demonstrated through numerical examples, the method is used to estimate the flutter reliability of a suspension bridge. The uncertainties such as material properties, geometric parameters, structural damping ratio, flutter derivatives and extreme wind velocity at the bridge site are considered. The example suspension bridge is the Jiang Yin Bridge with a main span length of 1385 m built in China. The results show that the proposed method based on an empirical formula in which the limit state function is explicitly represented as a function of variables overestimates the flutter reliability of suspension bridges. The actual flutter reliability should be more accurately analyzed using the proposed method based on the deterministic finite element method in which the limit state function is implicitly represented as a function of variables. Finally, the most influential random variables on flutter reliability of suspension bridges are identified by using a sensitivity analysis. 相似文献
38.
Sensitivity analysis of steel buildings subjected to column loss 总被引:1,自引:0,他引:1
In this study, the sensitivity of design parameters of steel buildings subjected to progressive collapse is studied. To this end, design parameters such as yield strengths of beams, columns, and braces, live load, elastic modulus, and damping ratio were considered as random variables. The Monte Carlo simulation, the Tornado Diagram analysis, and the First-Order Second Moment method were applied to deal with the uncertainties involved in the design parameters. The analysis results showed that among the design variables beam yield strength was ultimately the most important design parameter in the moment-resisting frame buildings while the column yield strength was the most important design parameter in the dual system building. Sensitivity of the vertical displacement to uncertain member strength showed that progressive collapse mechanisms of the moment-resisting frame buildings and the dual system building completely differed due to different patterns of the vertical load redistribution. 相似文献
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Random material variability effects on full-strength end-plate beam-to-column joints 总被引:1,自引:0,他引:1
In the seismic design of steel frames, beam-to-column joints are generally designed as full strength joints in order to avoid their engagement in the plastic range promoting the location of plastic hinges at the ends of the connected beams. In this paper, the reliability of the criteria to design full strength beam-to-column joints is investigated. In particular, in the first part of the work, starting from probabilistic analyses accounting for random material variability of connecting elements, the reliability of the design criteria suggested by codes is analyzed. Successively, on the basis of the obtained results, a new design criterion able to account for both the random material variability and the overstrength exhibited by the beam before the occurrence of local buckling is proposed. 相似文献