泉州湾跨海大桥主桥主梁施工技术

Construction Techniques for Main Girder of Main Bridge of Quanzhou Bay Bridge

泉州湾跨海大桥主桥为(70+130+400+130+70)m双塔结合梁斜拉桥,主梁为PK钢-混凝土结合梁,主梁单幅含风嘴宽27.41 m,梁高3.5 m。该桥主梁采用整梁段悬臂拼装架设,梁段之间采取"干拼法"连接,U形钢箱梁之间采用全焊接连接,在混凝土顶板之间涂抹环氧胶并施加预应力连接。该桥主梁施工主要包括预制拼装和架设两个阶段,在预制拼装阶段,采用钢桁架方案实现了主梁梁段反拱;在架设阶段,通过对梁段空中姿态预控,以及混凝土板上、下临时预紧力配合进行梁段纵向高程调整,在混凝土顶板间设置钢板垫块进行轴线偏差调整,通过设置湿接缝调整里程偏差,中跨采用配切合龙。采用"干拼法"施工,该桥合龙后,梁顶高程偏差小于5mm,满足设计要求。

The main bridge of Quanzhou Bay Bridge is a double-pylon cable stayed bridge with span arrangement （70-～130q-400q-130q-70） m. The main girder of the bridge is the steel and con- crete composite girder of Pasco-Kennewick Bridge type and a single part of the girder including the wind fairing is 27.41 m wide and 3.5 m deep. The main girder was constructed by the cantilever assembling and erection in each full girder segment. The girder segments were connected by the dry joint method, of which the segments of the U-shape steel box girder were connected by all- welding and the concrete deck slabs on the steel box girder were connected by applying epoxy glue in between the slabs and the slabs were then prestressed. The construction of the main girder of the bridge mainly covered two stages of the prefabrication, assembling and erection. At the stage of the prefabrication and assembling, the girder segments were cambered, using the steel truss and at the stage of the erection, the longitudinal elevation of the segments was adjusted by pre-control- ling the segment posture in the air and by temporarily pre-tightening the upper and lower points of the deck slabs. The axial line offsetting of the deck slabs was adjusted by the steel plate pads set in between the slabs, the mileage offsetting was adjusted by casting the wet joints and the central span of the bridge was finally closed by match cutting. With the construction of the main girder u- sing the dry joint method, the offsetting of the girder top elevation after closure of the bridge is less than 5 mm and can satisfy the design requirements.