青岛海湾大桥混凝土墩的时变可靠度

分析了北方海域混凝土结构时变可靠度产生的原因,通过大量室内冻融试验研究,得出了混凝土结构在冻融作用下的弹性模量、抗拉、抗压等力学性能指标的损伤规律。建立了混凝土墩力学参数随冻融次数的衰减规律,继而转化为强度随时间的衰减规律。推导了混凝土结构在冻融环境下的时变可靠度的计算方法,并应用可靠度理论对海湾桥沧口段航道桥墩柱下部结构进行了数值分析,得出可靠度随时间的变化规律,为维护决策提供依据。

Time-dependent reliability of concrete pier of Tsingtao bay bridge

The time-dependent reliability problem of the concrete structure in northern sea regions of China was discussed.The degradation behaviors of the mechanical properties such as Young's modulus,compressive strength and tensile strength of the concrete structure after the freeze-thaw cycles were revealed through a great deal of in-lab freeze-thaw tests.The mechanical parameter degradation of the concrete pier with the freeze-thaw cycle number were obtained,and the strength-time degradation laws were abtained.A time-dependent reliability calculation method of the concrete structure in the freeze-thaw environment was proposed.The lower concrete structure of the pier of Cangkou sea-route of Tsingdao Bay bridge were analyzed numerically by the finite element reliability theory and the proposed method,and the reliability index variation with time was obtained,providing a reference for the engineering maintenance decision making of the pier.