大跨度转体施工工艺拱桥施工阶段稳定性问题研究

Study on stability of arch bridge during construction of long span rotating body construction technology

对采用转体施工工艺的三种大跨径上承式钢筋混凝土箱型拱桥,分别建立有限元模型。提取了一阶及二阶失稳模态,对转体施工阶段稳定性进行对比研究。结果表明,宽跨比在1/20以内的开口箱,在转体施工阶段,安全系数基本能满足要求;宽跨比较大,开口箱高度相对较高时,安全系数较高;转体阶段,在L/4处拱圈上缘可能会出现拉应力。

The finite element models of three kinds of reinforced concrete box arch bridges with long span and upper span are established respectively. The first-and second-order instability modes are extracted. The results show that the safety factor of the open box with a wide span ratio of less than 1/20 can meet the requirements in the construction stage of the rotating body. When the wide span is large and the opening box height is relatively high,the safety factor is high. In the transformation stage,the tensile stress may occur at the upper edge of the arch ring at L/4.