流溪河大桥主桥拆除施工技术

Construction Techniques for Demolition of Main Bridge of Liuxi River Bridge

流溪河大桥主桥为带挂梁的预应力混凝土T形刚构桥,由于交通量剧增,主桥桩基下沉,需拆除,提出利用2台50m架桥机联体并与主桥0号块临时固结,依次拆除左幅25mT梁和T构箱梁的11号块至1号块,将架桥机横移至右幅桥,按照左幅桥拆除方式拆除右幅桥。在悬挂T梁拆除过程中,采用逐片拆离的思路,先切割T梁片之间的连接,将2片T梁做为1组,并遵循"移梁不移机"的原则,采用顶升滑道方式横移T梁,最后将T梁吊离。在主桥T构箱梁拆除过程中,先安装吊具,按顺序切割箱梁顶板、底板、腹板,在箱梁节段分体后,利用牵引装置使梁体在空中转体,最后将梁体吊离。

The main bridge of the Liuxi River Bridge is a prestressed concrete T-frame bridge with suspended T-beams. The bridge needed to be demolished because of the dramatic increase of the traffic flow and the settlement of the pile foundations of the main bridge. For the demolition of the bridge, two sets of the 50 m overhead launching gantries were proposed to be used and the gantries were conjoined and temporarily fixed with the segment No. 0 of the bridge. With the gantries, the 25 m suspended T-beams and the segments No. 11 to No. 1 of the T-frame box beam of the left bridge were demolished in succession. The gantries were then transversely shifted to the right bridge and in the same demolition way of the left bridge, the right bridge would be de- molished. In the demolition of the T-beams, the beams were demolished beam by beam. The joints of the beams were cut off first, each 2 T-beams were divided into 1 group and on the princi- ple of ＂shifting the beams, but not shifting the gantries＂, the jacking-up slipways were used to transversely shift the beams and finally the beams were lifted away from the bridge. In the demo- lition of the T-frame box beam, the lifting riggings were installed first, the top slabs, bottom slabs and webs of the box beam were then cut in sequence and after the segments of the box beam were decomposed, the hauling devices were used tO rotate the beam in the air and finally the beam was lifted away.