波形钢腹板PC连续梁异步悬臂施工工序研究

Study of Unbalanced Cantilever Construction Procedure of PC Continuous Beams with Corrugated Steel Webs

为研究波形钢腹板PC连续梁桥在异步悬臂施工不同工序下的受力性能及施工工期,以主桥长360m的奉化江大桥为背景,采用有限元软件建立该桥箱梁的1~4号节段模型,分析按不同顺序浇筑箱梁顶、底板混凝土,吊装波形钢腹板时箱梁结构受力,并比较所需工期。结果表明:异步悬臂施工时,PC梁箱室中间小部分顶板混凝土处于受拉状态;波形钢腹板位移变化较大。若仅考虑结构受力,先浇筑前一节段顶板,再浇筑本节段底板,最后吊装后一节段波形钢腹板的方案施工期间挠度最小,受力最优;若综合考虑结构受力性能和施工周期的影响,同时浇筑前一节段顶板和本节段底板,最后吊装后一节段波形钢腹板的施工工序最优。

Different working procedures of the unbalanced cantilever construction will exert different effect on the load bearing behavior of the PC continuous beam bridge with corrugated steel webs and the construction schedule as well.The Fenghuajiang River Bridge having a main bridge of 360 m long was taken as the study background.The finite element software was used to establish the models of the No.1 to No.4 box beam sections,to analyze the load bearing behaviors of the box beam structure when the casting of the top and bottom slabs is carried out in different sequences and corrugated steel webs are also installed following different sequences.And the construction schedules were also compared.The results show that a small part of the top concrete slab in the central of the steel box beam was damaged.The displacement in the corrugated steel webs was great.If the load bearing capacity of the structure is the only factor considered,the scheme of casting the top slabs of a previous section first,then casting the bottom slabs of the current section,and installing the corrugated steel webs of the next section as the last step will result in minimum deflection and optimum load bearing condition.But if both the load bearing capacity of the structure and the construction schedule are considered,the scheme of casting the top slabs of a previous section and the bottom slabs of the current section in parallel and then installing the corrugated steel webs in the next section will be the optimum construction sequence.