宁波中兴大桥钢箱梁主跨合龙技术

Closure Technique of Main Span for Steel Box Girder of Zhongxing Bridge in Ningbo

宁波中兴大桥为(64+86+400+86+64)m的单索面矮塔斜拉桥,中跨有索区钢箱梁采用悬臂拼装方案施工,设置一个合龙段。为保证主梁合龙施工精度及质量,结合结构体系特点,中跨合龙采用配切合龙法。在合龙施工中,采取了免压重合龙观测技术、折线配切方法进行合龙段精细配切,并采用对拉螺栓对合龙段主梁快速临时锁定。该桥主梁合龙后,中跨合龙口最大高差分别为6mm,轴线偏差在9mm以内,焊缝宽度均为10-17mm。实践结果表明,该桥合龙施工技术切实可行、施工简便,合龙精度满足施工要求。

Zhong Xing Bridge in Ningbo is a(64+86+400+86+64)-m single-plane short-pylon cable-stayed bridge. Its midspan is the steel box girder constructed by the cantilever assembly scheme. A closure segment is set up. In order to ensure the construction accuracy and quality of closure construction of the main girder,and combined with the structural system characteristics, the mid-span closure adopts the matching cutting method. In the closure construction, the pressure-free closure observation technology and the kinked line matching cutting method are used to carry out the fine matching and cutting of closure segment, and the split bolt is used to carry out the quick temporary lock of the main girder of closure segment. After the main girder of this bridge is closed, the maximum height differences of the closure gap in the midspan is 6 mm, the axis deviation is within 9 mm and the welding joint width is 10 ~17 mm. the practical result shows that the closure construction technique of this bridge is practical and feasible, the construction is simple and convenient, and the closure accuracy can satisfy the construction requirements.