摘要
上海大庆桥为跨径60m的异型系杆拱桥,主拱横桥向反对称布置2片C50钢筋混凝土拱肋。该桥采用"先梁后拱"方案施工,即先采用满堂支架现浇系梁并张拉预应力,再在支架上现浇拱肋。在该桥施工中,先张拉吊杆再进行拱肋脱架,以改善裸拱圈在自重作用下的不利受力问题;在横梁与系梁间设置后浇带,以缓解横梁在顺桥向的受剪状态;在主梁支架拆除后再将桥面板与系梁、横梁联结,以减少桥面板参与系梁受力;吊杆采用三轮张拉方案,吊杆在拱肋脱架前进行首轮张拉,在系梁、横梁联结后进行第2轮张拉,第2轮张拉后拆除主梁支架,在桥面系施工后进行第3轮张拉;拱肋变形较大部位的吊杆先张拉,反之后张拉。该桥成桥后的结构线形与内力均满足设计要求。
The Daqing Bridge in Shanghai is a special-shaped tied-arch bridge with a span of 60 m.In the transverse direction of the bridge,the main arch consists of two C50 reinforced concrete arch ribs in anti-symmetric arrangement.It was constructed in a sequence of the tie beams first and arch ribs late,i.e.the tie beams were cast in situ and the prestress was tensioned on the staging first and then the arch ribs were cast in situ on the scaffoldings.The tensioning of the suspenders before the removal of the scaffoldings of the arch ribs could solve the problem of the unfavorable stresses which would occur due to the naked arch ribs under the self weight.The post-cast strips were set between the inner cross beams and tie beams to relieve the shear stresses of the cross beams in the longitudinal direction.To reduce the force applied on the bridge deck via the tie beams,the bridge deck was connected to the tie beams and cross beams after the removal of the girder scaffoldings.The suspenders were tensioned in three steps：the first tensioning was conducted right before the removal of the scaffoldings of arch ribs;the second tensioning was conducted after the connection of the tie beams and the cross beams,after which the girder scaffoldings were removed;the third tensioning was conducted after the floor system was finished.The suspenders at the places with large deformation on the arch ribs were tensioned first or otherwise later.The finished bridge structure could meet the design requirements both in structural alignment and internal force.
作者
白金超
BAI Jin-chao(Shanghai Municipal Planning ＆ Design and Research Institute,Shanghai 200031,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2018年第3期116-120,共5页
Bridge Construction
关键词
拱桥
异型拱肋
现浇法
拱肋脱架
后浇带
吊杆张拉
桥梁施工
arch bridge
special-shaped arch
cast-in-situ method
removal of arch rib scaffol-ding
post-cast strip
tensioning of suspender
bridge construction
