| The partial cable-stayed bridge with corrugated steel webs is a new type of bridge which combines corrugated steel webs box-girder bridge and partial cable-stayed bridge.The new bridge has good performance,and has been used in bridge construction at home and abroad.At present,there are few researches on the shear lag effect of this new bridge.In this thesis,a partial cable-stayed bridge with single-box four-cell corrugated steel webs is used as the engineering background to research its shear lag effect during construction.The completed work includes:(1)The structure of partial cable-stayed bridges with corrugated steel webs and the concept of shear lag effect are introduced,and the analysis methods and research work on shear lag effect at home and abroad are reviewed.(2)By the bar simulation method in theoretical analysis,a formula for calculating the shear lag effect of corrugated steel webs composite box-girder bridge is derived.The results are verified by finite element model.(3)The variation rule of shear lag effect in the whole construction process of partial cable-stayed bridge with corrugated steel webs is analyzed.A spatial frame finite element model and a spatial solid finite element model are established to accurately simulate the construction process.The theoretical stress values of box-girder section are analyzed and compared with the measured stress values collected in construction monitoring,and the correctness of the models is verified.Three control sections near block zero of the main girder are selected to analyze the shear lag effect under different construction conditions.The results show: when the single-box four-cell partial cable-stayed bridge with corrugated steel webs is advanced from the short cantilever state to the maximum cantilever state during the construction,the shear lag coefficients of the top and bottom of the control sections gradually increases,and the peak of the coefficients appears at the maximum cantilever state;after the completion of bridge construction,the shear lag coefficient gradually decreases and the trend of change is obvious.(4)The finite element models of the corrugated steel webs composite box-girder bridges with different beam widths,beam heights and concrete roof thicknesses are established,and the shear lag effect of box girders is analyzed.According to the analysis and comparison,the transverse width of the box girder and the thickness of the concrete roof have a great influence on the shear lag effect of the sections. |
