Research On The Mechanical Performance And Rationality Of Partially Cable-Stayed Bridges With Corrugated Steel Web PC Composite Box Girders

Waveform steel webs are a new type of structure that has been widely used in China in recent years.Engineers have widely applied this type of structure to beam bridge systems,and with the development of material technology and construction techniques,waveform steel webs have been applied to cable-stayed bridges,as well as some cable-stayed bridges between beam bridges and cable-stayed bridges.At present,there have been many studies on partially cable-stayed bridges with corrugated steel webs in China,but the span is mainly concentrated in the range of 120 m to 200 m.However,partially cable-stayed bridges with corrugated steel webs of extra large spans have not yet appeared in China.Therefore,it is necessary to conduct a comprehensive study on partially cable-stayed bridges with corrugated steel webs of extra large spans.This article combines the design of a partially cable-stayed bridge with a large span concrete main beam(main span 296m)under construction to design a partially cable-stayed bridge with a corrugated steel web PC composite box girder.Through finite element analysis,the mechanical performance of some cable-stayed bridges was studied,and the rationality of the application of corrugated steel webs in large-span partially cable-stayed bridges was explored.This article mainly completes the following work:(1)This article establishes a partial cable-stayed bridge model for concrete main beams based on beam elements and a full bridge model for box girders with corrugated steel webs through Midas Civil.It analyzes the impact of using corrugated steel webs on section stiffness and material consumption of main structures,and compares the changes in internal forces and stresses during the operation and construction stages of the two types of bridges.(2)Using the finite element software FEA NX,a half superstructure model and a stability analysis model of corrugated steel webs were established for the entire bridge.The stress of the concrete top and bottom plates and corrugated steel webs of a partially cable-stayed bridge with a large span PC composite box girder with corrugated steel webs were calculated and analyzed,with a focus on studying the buckling stability of the corrugated steel webs.(3)Introduced the stability theory of bridge structures,sorted out the buckling theory of corrugated steel webs,introduced three forms of buckling failure of corrugated steel webs,and listed the calculation methods of local buckling,overall buckling,and combined buckling.(4)Based on the formula for calculating the ultimate buckling strength of corrugated steel webs,the design buckling critical curves of four commonly used types of corrugated steel webs in the specifications were derived and summarized,providing guidance for design work.(5)Taking inspiration from the existing bridges,steel transverse connections are introduced into the design of corrugated steel webs,and the feasibility of improving the stability of corrugated steel webs through structural measures is studied.