悬索桥锚碇中大型锚固钢板空间叠加定位施工技术

Construction Techniques for Spatial and Overlaying Positioning of Large Scale Anchor Steel Plates in Anchorages of Suspension Bridge

南京长江第四大桥为双塔三跨悬索桥,南锚碇采用改进后锚梁锚固系统。单个锚体共9片锚固钢板,单片锚固钢板在工厂分块制作,工地分层安装。锚固钢板由工字梁与锚板组成,由于锚固钢板形状不规则、分层叠加安装次数多、空间定位精度要求高,因此需设置可靠的定位支撑系统。第1层锚固钢板全部依靠临时支架精确定位,叠加层锚固钢板与底层锚固钢板在锚板处通过螺栓及匹配槽口连接,锚板顶口依靠临时支架或已经安装好的锚固钢板定位,梁端均依靠临时支架定位。施工时通过在锚固钢板上布置监测点,采用合理措施调整底层及叠加层锚固钢板的位置达到精确定位要求。

The Fourth Nanjing Changjiang River Bridge is a two-tower and three-span suspension bridge. The anchor system of improved rear anchor beam is employed for the south anchorage of the bridge. A single anchor body contains 9 anchor steel plates and an anchor steel plate is fabricated in pieces in shop alld installed in layers at the construction site. The anchor steel plates are made up of I-beams and steel plates. The arrangement of the reliable support system is required for positioning of the anchor steel plates because of the irregular shapes of the plates, many times of installation of the plates in layers and high accuracy requirement for spatial positioning of the plates. The first （bottom） layer of the anchor steel plate is accurately positioned completely by the temporary support, the overlaying anchor steel plates and the bottom layer anchor steel plate are connected via bolts and matching grooves. The top openings of the anchor steel plates are positioned by the temporary support or the anchor steel plates already installed and all ends of the I-beams are positioned by the temporary support. In the construction process, the accuracy of installation of the anchor steel plates is achieved through the monitoring points set on the plates and adjusting of the positions of the bottom layer and overlaying anchor steel plates by rational measures.