鳊鱼洲长江大桥南汊航道桥塔梁同步施工测量技术

Measurement Techniques Used in Pylon and Girder Synchronous Construction of Bianyuzhou Changjiang River Bridge

安九铁路鳊鱼洲长江大桥南汊航道桥为(50+50+224+672+174+50+50+50)m钢箱混合梁斜拉桥,主跨和辅助跨采用钢箱梁,桥塔采用H形塔,黄梅侧桥塔采用塔梁同步方案施工。针对塔梁同步施工测量重难点,运用莱卡TM50全站仪自动化实时采集塔端监测数据,利用Matlab程序计算塔柱纵向偏移量以修正塔偏;在塔柱“零状态”下采用天顶距法传递高程基准,采用精密全站仪后方交会设站传递平面基准至塔柱顶端测量平台,基于内控法进行钢锚箱安装及精密定位测量;采用全站仪三维坐标法进行钢箱梁安装定位,基于相对高差法控制钢箱梁安装线形。塔梁同步施工测量期间,通过加密控制网、全站仪自动观测、塔偏修正、钢锚箱精确定位及钢箱梁安装等技术,使塔柱和主梁施工节段能正确无误地顺接,在保证施工质量的同时缩短了施工工期。

The south branch navigation channel bridge of Bianyuzhou Changjiang River Bridge of the Anqing-Jiujiang Railway is a cable-stayed bridge with a main span of 672 m,two side spans of 224 m and 174 m,and five spans of 50 m.The superstructure consists of steel and concrete box girders,specifically streamlined steel box girders in the main span and auxiliary spans.The pylons are H-shaped structures,and the Huangmei-shore pylon was constructed in parallel with the girders.Considering the measurement focus and complexities in the pylon-girder synchronous construction,a Leica TM50 total station was used to carry out real-time monitoring of the pylon head.The pylon column longitudinal offset was calculated in Matlab software for modification.When the pylon columns were in"zero state",the zenith distance method was used to transmit the elevation datum,and a total station intersection method was used to transmit the plan datum to the pylon-top measurement platform,with the internal control method,the steel anchor boxes were installed and precise positioning measurement was performed.The steel box girder installation positioning was carried out by the total station 3D coordinate measurement.The steel box girder installation alignment was controlled based on the relative height difference method.To ensure the accurate sequential connection of the pylon and main girder segments,a series of techniques were used,including thickening the control network,using total station for automatic observation,pylon offset modification,accurate steel anchor box positioning and steel box girder installation.The construction schedule was shortened without compromising the required quality.