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摘要为提高桥梁承载力评估的准确性,该文基于结构时变可靠度理论,提出了利用桥梁已有信息(包括荷载历史、性能劣化规律等)对桥梁初评承载力进行更新的方法。将结构承载力的衰减描述成完全相关的随机过程,将荷载历史描述成不同时刻相互独立的随机过程,给出了同时考虑承载力衰减规律、荷载历史及其不确定性的既有桥梁承载力更新的显式公式,并通过具体算例验证了该方法的准确性。利用该文方法,对比了考虑与不考虑荷载历史时的桥梁初评与更新后的承载力,以及在更新时考虑与不考虑承载力衰减的承载力更新效果。结果表明: 历史荷载越大,对承载力更新的效果越明显; 但若未同时考虑承载力的衰减,会高估桥梁的实际承载力,造成评估结果的不安全。
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| 关键词 ：既有桥梁,荷载历史,结构劣化,承载力,评估 |
Abstract：The load bearing capacity of existing bridges can be more realistically assessed using a method that assesses the capacity based on load history information using structural time-dependent reliability theory. The capacity degradation is described by a fully-correlated stochastic process and the loading history is described by a statistically independent stochastic process. An explicit formula is presented that takes into account the capacity deterioration and the uncertainties associated with the load history. Illustrative examples demonstrate the accuracy of this method. The method is then used to analyze the effects of loading history, with and without consideration of the resistance degradation, on the capacity assessment of existing bridges. Larger loading histories give a larger updated bridge bearing capacity. However, if the resistance degradation is ignored, the bearing capacity will be greatly overestimated, resulting in unsafe evaluation results.
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| Key words：existing bridgesloading historystructural deteriorationbearing capacityevaluation |
| 收稿日期: 2014-03-23 出版日期: 2015-05-15 |
| 基金资助:国家自然科学基金资助项目(50708052);清华大学自主科研基金资助项目(20121087910) |
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