钢管拱竖向转体施工技术

Vertical Rotation Construction Techniques for Steel Tube Arches

郑万高铁河南段张良镇跨南水北调干渠特大桥采用先梁后拱、卧拼竖转法施工。桥体主拱肋竖转体系的设计,在通索式竖转工艺基础上优化增设调塔索,可根据测量监测数据及时调整塔架,确保塔架始终处于竖直状态,受力更明确合理。采用配有液压自动夹片夹持器的起重动力千斤顶,具有自动化、多行程持力回放功能,解决了竖向转体过顶回放合龙方式的机械配套问题,且千斤顶置于梁底下操作和监控,避免了梁后端干扰,安全风险大大降低。理论计算与实测结合方式指导施工,确保了竖转过程中关键部位的应力在允许范围以内,成功地实现了两半拱平稳、准确竖转合龙。

The Zhangliangzhen Mega Bridge of the Henan Section of the Zheng-Wan Expressway spanning the Main Ditch of the South-Water-to-North Project is built by means of the Beam-before-Arch-and-Horizontal-Assembly-Vertical-Rotation Technique.The design of the vertial rotation system for the main arch rib of the bridge body is based on the the full-length-cable-type vertical rotation technology and optimized with the tower-adjusting cables added,in which case the tower may be adjusted in time accoding to the measured and monitored data so as to keep the tower always vertical,and reasonbly and clearly loaded.As jacks with automatic hydraulic grippers are provided,which have the automatic and multi-stroke power-holding playback function,the problem of mechanical matching is solved when the bridge body is vertically rotated over the top and needs to lower and meet the other beam section.Besides,jacks are placed,operated and monitored under the beam,interference with the beam-end is avoided,with risks in safety much reduced.The construction of the project is guided with both theoreticl calculations and the site survey,as a result of which the stress of the key parts in the process of the vertical rotation is kept within the range of the allowable values.In result,two halves of the arch are successfully and firmly made vertically rotate and accurately meet each other.