Analysis Of Cradle Scaffolding Spatial Stress In Cantilever Construction

Extradosed cable-stayed bridge is a new bridge-type between beam bridges and cable-stayed bridges,it contains the characteristics of they both.Because of its economic and landscape advantages,it is applied in bridge construction widely. Extradosed cable-stayed bridge is a multiply redundant structure,so construction process of the bearing structure produced significant influence.The construction control of main girder is the key point of the whole bridge construction.Cradle scaffolding is the main equipment in cantilever construction, The forms of cradle scaffoldings are many and varied,it developed rapidly in foreign countries. In China since the start using this technology has made great achievements. Cradle scaffolding is the operating platform throughout the construction process, and also belongs to the high-altitude operations,therefore, its safety is extremely important. Cradle scaffolding must satisfy the demands of sufficient strength, stiffness and stability to ensure the safety of the whole structure and constructors. The significance of this study lies in analysis of the cradle scaffolding structure to ensure the safety of the bridge structure and itself in the construction process.Based on the construction of Chang Shan Bridge(Three span prestressed concrete extradosed cable-stayed bridge with Twin Towers and single cable),this paper describes the structure、 mechanical characteristics and operational principle of diamond-shaped cradle scaffolding.Using the Midas/Civil analysis software to establish the appropriate model to analyse the mechanical characteristics of cradle scaffolding.and calculate the main force position.The cradle scaffolding load test determine the carrying capacity and eliminate the impact of inelastic deformation of the construction.Analysis of the main beam of the construction phase, establish the whole bridge finite element analysis model by Midas Civil in cantilever construction stage and discuss the impact of the structure in the construction process,the load and mobile,of the Cradle scaffolding structure,and determine the focus of attention in the constructioncontrol,to ensure the security of the whole structure.