连续梁大边跨直线段支架挂篮组合施工关键技术研究

福平铁路平潭海峡公铁两用大桥位于复杂海洋环境,特殊的施工条件造成大桥施工中要对常规的施工方法进行创新。大桥公路B42#~B50#连续梁原设计为(40.6+6×64+40.6)m,因B42#墩处海床面为裸岩陡坡,施工困难,经变更后该联连续梁孔跨变为(64+40.6+5×64+40.6)m,边跨64 m,其中直线段20.9 m。边跨墩位处无法搭设满堂支架施工边跨直线段。经计算分析将边跨直线段20.9 m,分为4节段施工:梁端9.2 m、5.7 m节段采用在承台上搭设倒梯形支架施工,其余两节段3.5 m、2.5 m采用挂篮悬臂施工的方案。该施工方案中通过采取在梁端两侧临时固结,顶部外加压重的措施,有效解决了直线段挂篮悬臂施工的平衡难题,为类似的跨海湾、河流工程提供了一种施工思路和施工经验。

Study on Key Technology of Bracket and Hanging Basket Combination Construction of Large Side Span Continuous Beam in Straight Line Section

The Pingtan Channel Highway and Railway Combined Bridge in Fuping Railway is located in a complex marine environment.The special construction conditions make it necessary to innovate the conventional construction methods.The original design of B42#~B50#continuous beam of the bridge is(40.6+6×64+40.6)m.Due to the steep slope of bare rock on the seabed of the B42#pier,the construction is difficult.After modification,the span of the continuous beam is(64+40.6+5×64+40.6)m,and the side span is 64 m,of which the straight section is 20.9 m.At the position of side span pier,full support cannot be set up for construction side span straight section.According to the calculation and analysis,the straight section of the side span is divided into four sections:section 9.2 m and section 5.7 m of the beam end are constructed by placing inverted trapezoid bracket on the platform;the other two sections of 3.5 m and 2.5 m are constructed by hanging basket cantilever.In this construction scheme,the balance problem of hanging basket cantilever construction in straight section is effectively solved by adopting the measures of temporary consolidation on both sides of the beam end and heavy pressure on the top,which could provide a kind of construction idea and experience for similar cross-bay and river projects.