在役钢筋混凝土渡槽时变模糊可靠度分析

Time dependent fuzzy reliability analysis of in-service reinforced concrete aqueduct

为了更合理地评价渡槽结构在使用过程中安全性能随时间变化的情况,基于在役钢筋混凝土渡槽结构,考虑时间因素,并考虑混凝土碳化引起结构耐久性下降因素的随机性与模糊性,以渡槽结构混凝土碳化深度为基本控制参数,利用一次二阶矩法,建立了混凝土碳化深度随时间变化的时变模糊可靠度模型,运用MATLAB编制相应的程序,针对工程实例进行计算分析。计算结果表明:考虑时间因素,可以较好地反映渡槽结构随时间变化的动态可靠性指标,便于更加准确地掌握渡槽的检修时间;在以时间为因素的基础上,考虑变量的随机性与模糊性所得到的解比经典可靠度解偏小,这与实际工程相符,更加接近于工程真实情况,可为工程设计和后期维修提供更多的参考信息。

In order to evaluate the time-dependent safety performance of aqueduct structure during operation more reasonably, a time-dependent fuzzy reliability model for the time-varying concrete carbonation depth is established with the first-order second-moment method by taking the concrete carbonation depth of aqueduct as the basic control parameter under the considerations of the time factor and both the randomness and the fuzziness of the factor of the structure durability decrease caused by the concrete carbonation on the basis of the structure of in-service reinforced concrete aqueduct, and then the relevant calculation and analysis on engineering case are carried out with the corresponding program made with MATLAB. The calculation result shows that the time-dependent dynamic reliability index of the aqueduct structure can be better reflected under the consideration of time factor, which is convenient for more correctly grasping the maintenance time.On the basis of considering the time factor, the solution obtained by considering the randomness and fuzziness of variable is a little bit less than the classical reliability solution, which is consistent with that from the actual project and more close to the real engineering situation, thus can provide more referential information for the engineering design and the late maintenance.