马鞍山长江公路大桥钢塔线形控制技术

Geometrical Shape Control Techniques Used to Steel Towers of Maanshan Changjiang River Highway Bridge

马鞍山长江公路大桥左汊主桥为(360+2×1 080+360)m的三塔两跨悬索桥,中塔采用钢-混叠合、塔梁固结门式结构,下塔柱为预应力钢筋混凝土结构,上塔柱为钢结构,钢塔共分21个节段,首节采用浮吊安装,标准节段长6m,最大起吊重达235t,采用塔吊进行安装。为确保钢塔线形满足要求,对影响钢塔安装精度因素进行分析,形成以控制钢塔制造质量为核心、钢塔首节段安装精度为基础的线形控制流程,对钢塔节段进行工厂制造控制和现场安装控制。工厂制造控制包括零部件加工、块体制作、节段组拼、端面机加工、预拼装;现场安装控制包括首节段安装、标准节段安装、横梁与钢塔的连接。实践表明,该桥采用以控制钢塔制造精度为核心的钢塔线形控制技术进行钢塔架设施工,施工过程中钢塔制造精度和安装精度满足要求,实现了钢塔线形控制的目的。

The left main bridge of Maanshan Changjiang River Highway Bridge is a threetower twomain span suspension bridge with span arrangement of （360＋2 ×1 080＋360） m .The central tower is a doorshaped steelconcrete hybrid structure which is fixed to the stiffening girder . The lower tower legs adopt the prestressed reinforced concrete structures while the upper tower legs are steel structures .The steel towers consists of 21 sections ,the first section is installed by floating crane .The standard sections installed by tower cranes are 6 m long ,with a maximum lifting weight of up to 235 t .To make sure that the geometrical shape of steel tower meet the requirements ,the factors that have influence on the installation precision of the steel tower were analyzed ,forming a geometrical shape control procedure that focus on the control of the fabrication quality of the steel tower and bases on the installation precision of the first section of the steel tower ,and the corresponding controls for the factory fabrication and field installation of the steel tower sections were conducted .The factory fabrication control covers the spare parts and components processing ,sectional unit fabrication ,sectional assembling ,and end surface machining ,and preassembling .T he field installation control items include first section installation ,standard section installation ,and the connection of the cross beams and steel tower .The engineering practice proves that by using the geometrical control technique taking the control of the fabrication precision of the steel tower as the key in steel tower erection ,the fabrication and installation precision of the steel tower during the construction process met the requirements ,achieving the goal of steel tower geometrical shape control .