基于结构可靠度的劣化桥梁维护方案成本优化研究

STRUCTURAL RELIABILITY-BASED LIFE-CYCLE COST OPTIMIZATION OF MAINTENANCE INTERVENTIONS FOR DETERIORATING BRIDGES

在桥梁管理系统中劣化桥梁结构的现有状态的评估和将来状态的预测是非常重要的内容。在预测过程中一方面应计算时变荷载和抗力,另一方面需考虑维持桥梁安全和服务水平的维护策略,这使得桥梁将来状态的预测变的十分复杂和困难。在劣化结构寿命评估和预测过程中要考虑各种参数的不确定性。在改进的结构劣化模型基础上,推导了在各种维护策略下的可靠指标评估公式,研究了维护方案与结构可靠指标的相互关系。提出了在分析寿命周期内的总成本中各单项成本的计算公式。根据寿命周期内成本现值最小的原则,在满足结构性能要求和预算限制约束下,决策出在分析周期内成本和性能都满足要求的维护方案。最后,以劣化的水泥混凝土桥面铺装为数值算例,证明了该方法的可靠性。

The assessment of the current state and the prediction of the future condition of the deteriorating structures are crucial issues for bridge management. Time-varying loads, deteriorating resistance, as well as maintenance interventions for the sake of safety and serviceability, make the prediction very difficult. In order to perform a realistic life-cycle performance analysis of deteriorating bridge under different maintenance scenarios, the uncertainties involved have to be considered. Based on the improved deterioration model, a set of calculation formulas for reliability index under different maintenance strategies are proposed in this paper, and calculation methods for indirect maintenance cost in service time are presented. By minimizing the present value of life-cycle cost, the maintenance strategies are identified, which best balance cost and reliability index profiles over a specified time horizon under constraint of structural life-cycle performance and fiscal budget. Finally, the proposed method is applied to a deteriorating bridge surface to demonstrate its feasibility.