摘要
为给钢-混凝土组合梁中支点负弯矩段混凝土施加预应力,以上海崇明越江通道长江大桥工程B4标段(85+5×105+90)m钢-混凝土组合结构连续箱梁为例,采用先简支后连续配合中支点桥面板滞后结合和支点升降法等措施进行施工。组合梁整孔预制(中支点两侧各约7.5m的混凝土顶板先不结合),运抵现场整孔架设后浇注底板双结合段混凝土,待底板混凝土达到一定强度后起顶组合梁,浇注顶板湿接缝混凝土,然后落梁进行后续施工。监测结果表明,体系转换完成后、二期恒载铺设前各墩墩顶混凝土顶板压应力储备为3.01～4.70 MPa,在二期恒载铺装前桥面线形的实测值与设计值偏差普遍在3cm以内,墩顶体系转换时应力和线形控制较好。
To apply prestress to the concrete in the girder section with central support and hogging moment of the steel-concrete composite girder, the Phase B4 of the Changjiang River Bridge Project on the Shanghai-Chongming River Crossing Passage, a（85＋5×105＋90） m con-tinuous steel-concrete composite box girder bridge, was cited as a case. The bridge was construc-ted following a systematic sequence of transforming from a simply-supported structure to a con- tinuous structure, during which the measures of binding the bridge slab at the central support late and using the support raising and lowering method were taken. The composite girder was precast span by span （the top slab with a length of about 7.5 m on the two sides of the central support were not bond in advance）, after the composite girder was erected span by span at the bridge site, the concrete of the bottom slab of two composite sections were cast. When the concrete of the bottom slab reached the prescribed strength, the composite girder was jacked up, the wet joint concrete in the top slab was cast, then, the girder was lowered into place, and the follow-up con-struction work was carried out. The results of the monitoring indicated that after the system transformation, the tensile stress reserve in the top slab atop each pier was 3.01-4.70 MPa be-fore the secondary dead load was applied; the differential value between the calculated geometry and the designed geometry was usually within 3 cm before the application of the secondary dead load, the stress and geometry got good control during the systematic transformation atop piers.
出处
《世界桥梁》
北大核心
2013年第1期22-25,共4页
World Bridges
关键词
连续梁桥
钢
混凝土组合梁
墩顶负弯矩段
滞后结合
支点升降法
continuous girder bridge
steel-concrete composite girder~ hogging moment sec-tion on pier top
hysteretic binding
support raising and lowering method
