Study On Shear Strength And Construction Technology Of Composite Girder Bridge With Corrugated Steel Webs

In recent years,China has vigorously developed steel structure and steel-mixed composite structure,composite box girder bridges with corrugated steel webs as an economical and reasonable new bridge structure in the combined structure,using high-strength and lightweight corrugated steel plate instead of concrete on the web,making full use of the material properties of concrete and corrugated steel webs and reducing the weight of the structure.This new type of bridge structure has received extensive attention in the field of bridge engineering.As the span of the bridge continues to increase,the form of the bridge is gradually replaced by a more reasonable variable section form from the original equal-section structure.The shear performance of steel webs in corrugated steel web bridges is the focus of our attention.However,when the shear stress calculation theory of existing equal-section corrugated steel web bridges is applied to variable-section box girder,the research conclusion is too conservative,and the actual stress state of the bridge is significantly different,so the calculation of shear stress needs to be further deepened.At the same time,there is a large shear force in the root section of the corrugated steel web bridge,and a section of lining concrete is often used.Sharing the shear force of steel webs and alleviating the stress concentration problem of steel webs,in order to improve the theory of shear stress calculation of corrugated steel webs,it is necessary to make a systematic study on the influence of lining concrete;Most of them use cantilever construction,but in the corrugated steel web bridge,due to the strong bearing capacity of the steel web,the cantilever construction method has a new branch--RW method.The bridge engineers mostly focus on the new method.In the local stability of the steel web during the construction of the hanging basket,there are few studies on the two methods,and it is necessary to further deepen.Long Span Bridges variable cross-section corrugated steel web,the shear performance and a study cantilever construction technology for corrugated steel webs bridge,the main work is as follows:(1)The basic structure of the corrugated steel web bridge and its structural characteristics are elaborated,and the application status of the corrugated steel web bridge at home and abroad and its current status of shearing and construction technology are systematically described.(2)Based on the theory of material mechanics,considering the internal force balance of the micro-segment and the “variable-section effect” of the bridge,the general formula for calculating the shear stress of the corrugated steel web and th e formula of the web bearing shear ratio are derived,and the examples and the entity are limited.The calculation formula is verified by the combination of the elements.At the same time,the relationship between the shear stress of the corrugated steel w eb and the line shape of the beam is studied.The steel of the corrugated steel web bridge considering the linear shape of the bridge beam is improved.Web shear stress calculation theory.(3)Based on the finite element analysis method,the finite element analysis method is used to parameterize the influence of the thickness of the lining concrete from 15 cm to 40 cm and the creep effect on the shear resistance of the corrugated steel web bridge,further enriching the The shear theory of bridge structures.(4)Based on the research of the supporting project,firstly,based on the characteristics of the hanging basket layout and the load distribution of the hanging basket,the full-bridge solid finite element model based on the two cantilever construction methods is established to simulate the whole process construction;then the comparative analysis The advantages of RW method and traditional cantilever construction method in construction technology,construction period and economy;finally,the finite element analysis obtained the two methods in the construction process and the results of normal stress and shear stress and deflection of the box girder after the bridge.The difference of the mechanical properties of the whole structure under the two methods is compared.The systematic research on the difference between the RW method and the traditional cantilever method provides theoretical support for the further promotion of the RW method in the corrugated steel web bridge.