混凝土桥梁加宽改造后下部结构时变可靠性分析  

Time-dependent reliability of the substructure for widened concrete girder bridges

作　　者：方志[1] 董华平[1] 

机构地区：[1]湖南大学土木工程学院,长沙410082

出　　处：《桂林理工大学学报》2016年第4期707-712,共6页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(51278182)

摘　　要：为研究混凝土收缩徐变差及新旧结构间的基础沉降差对加宽后桥梁下部结构可靠指标的影响,以一座4×25 m多跨预应力混凝土先简支后连续T梁桥(已运营15年、加宽后结构的后续使用年限要求为85年)的加宽设计为对象,采用Midas建立空间梁格模型,用MATLAB软件计算了加宽改造前后下部结构的时变可靠性。结果表明:加宽改造后继续运营85年,仅考虑混凝土收缩徐变差的影响时,下部结构的可靠指标下降了16.20%,进一步考虑新旧结构间基础沉降差的影响时,下部结构的可靠指标则降低了32.59%。This paper studies the shrinkage and creep difference of concrete and foundations settlement difference between the old and new structure on the reliability index of widened bridge substructure.The research was carried on a widened prestressed concrete simply supported-to-continuous T-girder bridge with the span of 4×25 m,which was built 15 years ago,and expected to go on 85 years working after widened.Then we set up space beam grillage model by Midas and Matlab Software to analyze the time-dependent reliability of the bridge substructure before and after widened.The results showed that the index of time-dependent reliability of the bridge substructure decreased 16.20% if only considered the difference of shrinkage of concrete and creep after being operated for 85 years.The index of time-dependent reliability of the bridge substructure decreased 32.59% when further considered the foundations settlement difference between the old and new structure.

关 键 词：混凝土桥梁 加宽改造 收缩徐变差 基础沉降差 时变可靠度 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]