UHPC在T梁桥错孔拼宽湿接缝中的设计研究

Research on Design of UHPC in Staggered Wide Wet Joints of T⁃beam Bridge

装配式桥梁拼宽改造会出现错孔拼宽的情况,由于新旧桥错孔布置导致活荷载作用下新旧桥竖向变形在横向不协调,常规的普通混凝土拼接湿接缝方案难以满足车辆荷载产生的横向拉应力。以某高速公路改扩建项目中3×30m预应力混凝土T梁错孔拼宽改造为背景,在常规对孔拼接缝方案的基础上,结合超高性能混凝土(UHPC)抗拉性能,研究了一种不等宽柔性拼接方案,并采用有限元软件建立在最不利错孔15m情况下T梁实体模型,分析温度、车辆荷载、沉降对T梁拼接缝处的受力性能。结果表明:该结构在单项运营荷载及运营荷载组合作用下,结构受力满足材料性能要求,方案可行。

The widening of the prefabricated bridge will be widened by staggered holes.Due to the staggered arrangement of the new and old bridges,the vertical deformation of the new and old bridges under the action of live load is not coordinated in the transverse direction.The conventional ordinary concrete splicing wet joint scheme is difficult to meet the transverse tensile stress generated by the vehicle load.Taking the widening of 3×30m prestressed concrete T⁃beam in a highway reconstruction and expansion project as the background,based on the conventional hole splicing joint scheme,combined with the tensile performance of ultra⁃high performance concrete(UHPC),a flexible splicing scheme with unequal width was studied.The finite element software was used to establish the solid model of T⁃beam under the most unfavorable staggered hole of 15m,and the influence of temperature,vehicle load and settlement on the mechanical performance of T⁃beam splicing joint was analyzed.The results show that the structure meets the material performance requirements under the action of single operating load and operating load combination,and the scheme is feasible.