现浇空心板梁桥纵向开裂成因分析与试验研究

摘要

既有现浇空心板梁桥纵向开裂问题较多,为研究既有现浇空心板桥梁纵向开裂的原因,采用有限元方法,对有较多纵向裂缝的某地方公路现浇钢筋混凝土空心板梁桥进行空间模拟,分析底板厚度、板高、宽跨比对现浇空心板梁桥力学性能的影响.计算结果表明,该空心板桥梁强度和刚度均不能满足规范要求,板高度不够和宽跨比较大是该桥梁出现纵向开裂的主要原因;底板较薄、板高较小、宽跨比较大的现浇空心板梁桥极易出现纵向开裂.随着底板厚度、板高度的增大,跨中最大挠度和横向最大拉应力减小;随着板宽跨比的增大,跨中最大挠度和底板纵向最大拉应力减小,底板横向最大拉应力加大.同时根据试验和分析结果,提出了现浇空心板梁桥纵向开裂的防治措施.%Based on the finite element analysis software,the spatial analysis of the DongGuan local highway X232 line of a cast-in-place reinforced concrete hollow slabs bridge has carried on the stress and deflection distribution characteristics.And it also analyzed the principal cause of longitudinal cracks of the hollow slabs bridge from combining the bridge inspection with load experiment results.The result shows that the cast-in-situ hollow slabs bridge of the thin-bottom,less-height,large-wide span ratio causes longitudinal cracks easily.Secondly along with the increase of the bottom plate thickness and slabs height,the magnitude of maximum deflection and transverse tension stress decreasing.Thirdly with the increase of width span ratio,the magnitude of maximum deflection and bottom longitudinal tensile stress decreases,and magnitude of the maximum bottom transverse tensile stress increases.Furthermore,because of the large wide span ratio,the transverse stress will be huge,and with less slab height,the strength and stiffness of this hollow slabs bridge structure can not meet the standard requirements.It suggests that pasting steel is significant for strengthening the cross section.