考虑收缩徐变的混凝土T梁桥解联拼接效应分析及支座优化布置  

Analysis of Shrinkage and Creep Effect on Continuous Unit Division and Joining for Concrete T Beam Bridge and Optimized Arrangement of Bearings

作　　者：阳先全[1] 张龙[1] 常红航 

机构地区：[1]中交第二公路勘察设计研究院有限公司,湖北武汉430052 [2]新乡市住房和城乡建设委员会,河南新乡450000

出　　处：《世界桥梁》2015年第2期72-78,共7页World Bridges

摘　　要：为降低新、旧混凝土收缩徐变对长联混凝土T梁桥横向拼接的影响,指导其合理地拼接,以某22跨1联、跨径25m的混凝土T梁桥拓宽工程为背景,采用有限元法建立其横向拼接的空间模型,分析4种解联方案(1联22跨,2联11跨,4联5、6跨,6联2、4跨)下新旧混凝土收缩徐变差引起的结构纵、横向效应。结果表明:拼接后,新旧混凝土收缩徐变差在旧桥结构内产生显著的纵、横向效应,直接拼接或解为2联拼接时,最大横向位移均超出支座限值,结构甚至存在落梁风险,且旧桥外边梁和次边梁轴向拉、压力并存,受力较复杂;将旧桥解为100m和150m的短联后拼接可显著减小结构横向效应,且纵向受力简单、均匀。采用最小应变能准则法和目标优化函数法,对解为100m一联方案的支座布置进行优化。To reduce the shrinkage and creep of new and old concrete on the transverse joining of concrete T beam bridge with long continuous units and guide the rational joining of units,a concrete T beam bridge widening project which has a continuous unit of 22 spans of 25 m was taken as the study background.The finite element method was used to establish the spatial model of the transverse joints,to analyze longitudinal and transverse effect caused by the shrinkage and creep of the new and old concrete under four continuous unit division schemes,including a continuous unit of 22 spans,two continuous units of 11 spans,four continuous units of 5and 6spans and six units of 2and 4spans.The results indicate that after the joining,the shrinkage and creep of the new and old concrete exerts significant longitudinal and transverse effect on the old bridge structure.In the cases of direct joining or joining after being divided into two continuous units,the maximum transverse displacement exceeds the limit value of the bearings,therefore,the structure is threatened by the risk of girder collapse.Moreover,the axial tensile and compressive stress coexists in the outer edge beam and the subsidiary side beam of the old bridge,the load bearing condition is complex.However,if the old bridge is divided into the short continuous units of 100 mand 150mand jointed,the transverse effect of the structure would be considerably reduced and the longitudinal load path is simple and uniform.The minimal strain energy criterion method and the objective optimization function method were used to optimize the bearing arrangement of scheme of continuous units of 100 m.

关 键 词：预应力钢筋混凝土桥 T形梁 收缩徐变 解联拼接 支座布置优化 变形 轴力 应变能 有限元法 

分 类 号：U441[建筑科学—桥梁与隧道工程] U443.36[交通运输工程—道路与铁道工程]