Study On Shear Lag Effect Of Long-span Multi-box Corrugated Steel Webs PC Girder Bridge

The corrugated steel web composite box girder bridge is a new type of structural bridge.By using corrugated steel sheets instead of ordinary concrete webs,a new form of box girder is obtained.This new steel-hybrid composite structure is very stress-sensitive and easy to study and analyze.It has high utilization rate of materials,excellent durability and good economic benefits.Moreover,this type of bridge has a beautiful appearance and has certain ornamental properties in both the city and the scenic spot.Therefore,although this type of bridge appeared late,it has attracted great attention at home and abroad.The research on this type of bridge has obtained rich results and its application has become more and more extensive.In recent years,a lot of researches have been done on the new bridge structure of corrugated steel webs in China,and some research results have been achieved.Some developed countries in foreign countries have conducted in-depth research on this type of bridge and have achieved fruitful results.In comparison,China’s research in this area started late,and the research on the shear lag law of PC beam bridges with large span corrugated steel webs is relatively rare.In order to study the shear lag effect of long-span multi-chamber corrugated steel web PC composite box girder bridge,this paper uses Yuxi River Bridge as the engineering research background,and establishes the bridge by using professional finite element software Midas/Civil and Midas/FEA.Simulate 3D solid model and detailed structure analysis model.Through the numerical analysis of the bridge model and the actual measured value,the shear lag of different control sections and different load conditions is studied in depth.At the same time,several similar models were established to analyze the effects of different factors on the shear lag effect.The main research contents are as follows:(1)Based on the energy variational method,the shear lag coefficient of simply supported corrugated steel web composite box girder bridge under different types of loads is derived,and the shear lag coefficient of cantilever corrugated steel web composite box under different types of loads is derived.(2)The bridge solid model was built using the professional bridge finite element software Midas/FEA to carry out detailed modeling analysis.The shear lag effect of the same calculated section of the multi-chamber corrugated steel web continuous beam bridge at different construction stages was studied.(3)The finite element model of multi-chamber corrugated steel web continuous beam bridge is established by Midas/Civil,and the distribution Iaw of shear lag coefficient of this type of bridge along the longitudinal direction is analyzed.(4)Set different load conditions and study the shear lag of several key sections.By establishing the corresponding finite element model,the shear lag coefficient under the corresponding load conditions is calculated and compared,and the distribution law is analyzed.(5)Establishing the corrugated steel web box girder models with different aspect ratios,wide span ratios,cantilever ratios,corrugated steel web thicknesses and presence or absence of intermediate diaphragms,and analyze the distribution law of shear lag effect.And through the comparison,the main influencing factors are summarized.