樟树赣江二桥钢混叠合梁斜拉桥桥塔施工技术

Construction Techniques for Pylons of Steel-concrete Composite Beam Cable-Stayed Bridge of Ganjiang Second Bridge in Zhangshu

樟树赣江二桥为双塔双索面半飘浮体系叠合梁斜拉桥,其桥塔为钢筋混凝土结构,宝瓶形,中间设置3道横梁。为控制裂缝,下塔柱第1节2.0 m高塔根和塔座混凝土一并浇筑;在中塔柱,部分节段测量放样时有所偏移,同时在一定位置对桥塔施加横向预加力;上塔柱为锚固段,全段设有井字形预应力束。为解决施工精度要求高、工期紧的难题,通过空间三维精确测量定位,塔柱施工采用液压爬模技术,模板以直代曲;桥塔与中横梁异步施工。实践证明,该桥桥塔的施工质量、安全、进度均达到了预期效果。

Ganjiang Second Bridge in Zhangshu is the half floating system composite beam cable-stayed bridge with twin pylons and double cable planes. The pylons are the aquarius-shape curved reinforced concrete structures with three cross beam between the columns of the pylons. To control the cracks in the massive concrete components of the pylon, the first segment of a lower column with 2 m was concreted together with the pylon footing. In the middle pylon column, some segments were set out to drift while measuring lofting, and meanwhile the horizontal pre-jacking force was applied to the given parts of the column. Upper pylon columns were the anchoring segments, with well-shaped prestressing tendon in all segments. To solve the problem of the demanding construction accuracy and tight construction schedule of the pylons, on the basis of the three- dimensional spatial precise surveying and positioning, the columns were constructed by the hydraulic climbing formwork technique. The formwork was straight one, but was applicable to the curved parts. The supports for construction of the cross beams were the assembled steel pipe scaffolding system and the construction of the cross beams was carried out concurrently with the columns. Practice proves that the construction quality, safety and progress of the bridge pylons have all achieved the anticipated effect.