大跨度钢箱梁斜拉桥施工控制

Construction Control of Long Span Steel Box Girder Cable-Stayed Bridge

为保证厦漳跨海大桥北汊主桥(主跨780m的双塔双索面半飘浮体系钢箱梁斜拉桥)成桥后内力和线形满足设计要求,采用以无应力状态法为理论基础的施工控制方法,考虑结构非线性,进行参数识别和平差计算,根据桥梁结构特点确定合理的成桥及施工阶段状态,对该桥进行施工控制。在施工控制中利用无应力夹角确定钢箱梁现场安装位置,利用索长拔出量快速确定张拉索力,并根据大桥结构特点及温度变化情况,采用单侧顶推为主、配切为辅的中跨合龙方案,有效地控制了合龙风险。通过全面严格的施工控制,厦漳跨海大桥北汊主桥实现了高精度顺利合龙,桥梁线形及内力均符合设计要求。

To ensure that the internal force and geometric shape of the completed north main bridge （a semi-floating system steel box girder cable-stayed bridge with double pylons, double ca- ble planes and with a rain span 780 m） of the Xiazhang Sea-Crossing Bridge could meet the design requirements, the construction control of the bridge was carried out, using the control method based on the unstressed state method theory, the parameter identification and adjustment calculation that considered the structural nonlinearity and also the rational completed bridge and construction stage state determined according to the structural characteristics of the bridge. In the construction control, the unstressed included angles were used to determine the site installation locations of the steel box girder blocks, the pull-out amount of the cable length was used to rapid- ly determine the tensioned cable forces and in regard of the structural characteristics and tempera- ture changes, the scheme of pushing the steel box girder towards one side mainly and cutting the girder auxiliarily for closure of the central span was utilized and the purpose of effective control of the risk of the closure was achieved. Through the all-round and stringent construction control, the north main bridge was eventually closed smoothly with high precision and the geometric shape and internal force of the bridge could all satisfy the design requirements.