The Key Technology Researches On Girders' Cantilever Construction Of Extrodosed Cable-stayed Bridge With A Wide Deck

Recently, the bridges have been closely followed with rapid expansion of highways. Cable-stayed bridge with its own economical characteristics has developed rapidly and become popular around the world for less than half a century. Extradosed bridge as a new kind of bridge with its simple and light tower is widely used for the bridges with span range of 100-200 meters in recent 30 years. The extradosed bridge's emergence fills the blank area in the bridge span between cable-stayed bridge and continuous steel bridge. The construction of the main girder is the key point in bridge construction.Based on the construction of the West River Bridge-the typical extradosed bridge,the author conducts a study on the key technologies on cantilever construction. It describes the development of cantilever construction and gives a brief overview of the West River Bridge's project overview. Some typical cradle scaffoldings'designs and characteristics are introduced briefly. The entire engineer construction program is carefully designed then the diamond-shaped cradle scaffolding is designed on the specific characteristic of the engineering. The diamond-shaped cradle scaffolding's work principle and transfer mechanism are introduced and the entire structure is checked. The structure's finite element model is calculated using Ansys. The static load experiment was acted on the diamond-shaped cradle scaffolding to test the bearing capacity of test main trusses,the rationality of the structure,the quality of cradle scaffolding and the destruction resistant capability of hinge. The cradle scaffolding's assembly steps are introduced in detail according to the assembly program including running system- bearing system- hoisting system-bottom basket system-template system.Another important point in the cantilever construction is mass concrete casting of 0# blocks. The 0# block in the West River Bridge has big volume concrete, wide beam and long cantilever. The wide concrete box is easy to crack by shrinkage of concrete. The support cast-in-situ scheme on 0# block is proposed according to actual situation. The installation of level brackets, templates, reinforcement and prestressed pipe are designed detaildely. Measures are taken during the concrete casting in the paper to prevent cracking. Using cradle scaffolding is still the main trend in the cantilever construction. But the present cradle scaffolding's production to finalize the design series don't have certain condition, it provides modified space for the engineers.