厦漳跨海大桥北汊主桥配切-顶推合龙技术

Technique of Cutting-Pushing Closure for North Main Bridge of Xiazhang Sea-Crossing Bridge

厦漳跨海大桥北汊主桥为双塔双索面钢箱梁斜拉桥,主梁采用悬臂拼装施工,中跨合龙方案采用配切-顶推合龙技术:在合龙前对合龙口进行观测,并拟合出合龙口宽度～温度曲线,根据预测的合龙口宽度对合龙段下料,同时在塔梁临时锚固上对单侧主梁顶推和回移一较小位移。实践证明,该桥采用的配切-顶推合龙技术既能确保合龙段顺利吊入合龙口,又能达到理想的焊缝宽度,提高了合龙的可靠性,降低了结构安全风险。

The north main bridge of the Xiazhang Sea-Crossing Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes. The main girder of the bridge was erected by the cantilever assembling method and the central span was closed by the technique of cutting and pushing. Before the span was closed, the closure gap was continuously observed and the closure gap width-temperature curves were fitted. In the light of the predicted width of the closure gap, the material for the closure block was laid off and also at the temporary fixity of a pylon and the girder, the girder was pushed towards one side and/or withdrawn a little amount. Practice proves that the technique of the cutting and pushing closure applied to the bridge not only ensures the closure block to be smoothly lifted into the closure gap and but also achieves the ideal width of the welding seams. With the technique, the reliability of the closure is improved and the structural safety risk is decreased.