高墩大跨连续刚构桥施工期安全评价

针对高墩大跨连续刚构桥施工期结构概率失效的特性,提出了基于失效概率的安全评价方法.以徐水沟特大桥为工程背景,通过风险评定识别出施工最不利阶段--最大双悬臂时的主要风险因素即:节段特性模量的不确定性、梁体自重的不确定性以及预应力损失的不确定性.采用大型通用有限元程序ANSYS及蒙特卡洛法,计算徐水沟特大桥在最大悬臂时的失效概率,并确定施工期的目标可靠度.依据高墩大跨连续刚构桥施工期结构概率失效的评价结果,提出相应的风险控制措施.

Safety Assessment of Long Span Continuous Rigid-flame Bridges with High Piers in Construction Period

Aiming at the characteristics that the structure probability of high pier and long span continuous rigid-frame bridges is liable to fail,this paper presents a safety assessment method for this kind of bridges based on failure probability.By taking the Xushuigou Bridge as the engineering background,main risk factors in the most unfavorable construction period are identified to be the uncertainty of concrete segment elastic modulus,the uncertainty of beam weight and the uncertainty of the loss of pre-stress.By use of large universal finite element program ANSYS and Monte-Carlo random sampling method,the failure probability of Xushuigou Bridge is calculated and the target reliability of bridges in construction period is determined.Subsequently,some corresponding measures for the structure risk control of bridge are proposed according to the assessment results.