矮寨大桥钢桁梁节段立体试装技术

Stereo Trial Segmental Assembly Technique for Steel Truss Girder of Aizhai Bridge

矮寨大桥主桥为主跨1 176m的单跨钢桁梁悬索桥,钢桁梁节段由主桁架、主横桁架、上下平联及抗风稳定板组成,钢桁梁采用整体节段制造及架设方案施工。为了验证施工图纸的正确性、制造工艺的合理性、工艺装备的精确性,须在工厂进行钢桁梁试装。由于工地现场节段拼装条件限制,仅能实现单节段拼装,而且工期要求紧,需在高空实现多拼口的高精度对接,最终摒弃平面试装方案而采取了立体试装方案。立体试装采用单杆拼装的方法,选择了3个具有代表性的节段,按照下平面、腹杆、上平面的顺序拼装。该桥立体试装实施顺利,而且试装节段的桁高、节间长度等主要控制项点符合验收标准,栓孔通过率100%,验证了制作工艺和试装方案的合理性。

The main bridge of Aizhai Bridge is a single span steel truss girder suspension bridge with a main span of 1 176 m. The steel truss girder sections were composed of the main truss, main transverse truss, the upper and lower lateral bracings and the wind resistant stabilizing plates. The steel truss girder was constructed by the scheme of integral segmental fabrication and erection. To verify the accuracy of the construction drawing, the rationality of the manufacturing technique and the precision of the equipment, the trial assembling of the steel truss girder should be done in the workshop. Only single segmental assembly was available due to the limit of the seg mental assembling condition at the bridge site. Moreover, the construction schedule was very tight, the highprecision butt joint had to be realized above the land, so the stereo trial assembling scheme was finally chosen in preference to the plane trial assembling scheme. For the stereo trial assembling, the method of single chord assembling was used. Three representative segments were selected and assembled by the sequence of the lower plane, web chords and the upper plane. The stereo trial assembling of the bridge was carried out smoothly, the main controlling items, such as the truss height and length of the trial segments were accepted as qualified. The passing rate of the pin holes was 100 %, proving that the manufacturing technique and the trial assembling scheme are rational.