Theoretical And Experimental Research On Shear Lag Effect Of Extradosed Cable-stayed Bridge

Extradosed Cable-stayed Bridge is a new type bridge which is developed on the basis of Cable-stayed Bridge in recent years, it is between continuous beam (rigid frame) bridge and Cable-stayed Bridge. Extradosed Cable-stayed Bridge is widely applied because of its good economic performance and landscape effect. Based on Shiwan Bridge. model test and finite element technology, shear lag effect of single plane Extradosed Cable-stayed Bridge under both Prestressing and Vertical load is researched in this paper, which has a girder form of single-box-multiple-cell box girder with big cantilever> variable cross-section. The major contents and achievements of this paper are as follows:(1) Summarizing the development situation construction features, loading features and other features of Extradosed Cable-stayed Bridge, describing the theory and experiment research status of Extradosed Cable-stayed Bridge box girder’s shear lag at home and abroad, and also pointing out the problems that would be studied in the future.(2) Based on similarity theory, according to the dimension similarity criterion and the same reinforcement ratio, a single plane Extradosed Cable-stayed Bridge test model which has a girder form of single-box-multiple-cell box girder with big cantilever> variable cross-section is designed and made. In this paper, it designs the monitoring points arrangement test method, equipment’s choice and load conditions of the model experiment reasonablely.(3) Aiming at the test model, this paper researches it’s shear lag effect under three different load cases(only longitudinal Prestressing、both longitudinal Prestressing and Vertical concentration, both longitudinal Prestressing and Uniform load) by test, gets stress value of the main girder’s five typical section and displacement of the mid-span and cantilever, it truly reflects the shear lag effect’s distributive regularity of this bridge form’s gider.(4) With the model bridge, establishes the plane rod and space finite element model, and by numerical calculation, the shear lag effect of the model bridge is analyzed, the theory calculation is consistent with test result well according to coMParison, so it proves that the theory calculation in this paper is correct and reliable.(5) On the base of model test and finite element theory, aiming at the actual Extradosed Cable-stayed Bridge, establishes the space finite element model, meanwhile, the numerical simulation calculation of the actual bridge on construction stages is completed, and some meaningful conclusions are obtained which is valuable to design and construction.