Study On Calculation Method Of Transverse Internal Force Of Box Girder

There are many methods for the analysis of transverse internal force,such as rigid-supported method,"TYL" frame method,extended "TYL" frame method and so on.On the basis of the existing methods of transverse internal force analysis,this paper improves and analyzes the calculation method of transverse internal force of corrugated steel web box girder and ordinary concrete box girder.A more accurate and simple method for calculating transverse internal force is sought.This paper theoretically deduces the calculation formula of transverse internal force of traditional frame method,and verifies its correctness.Based on the traditional frame method,the author presents an improved method for calculating transverse internal force of single chamber corrugated steel box girder.In this paper,three different forms of web distortion stress distribution are considered,and the relevant formulas are derived theoretically.With the aid of an example,with different methods and different hypotheses,the final transverse internal moment of the key points are calculated in detail.The final transverse moment of the corrugated steel web box girder is compared and analyzed.It is found that the distortion warpage coefficient has little effect on the final transverse moment of the corrugated steel web box girder.In the design process,it can be assumed directly that there is no distortion warpage stress on the web.And the improved method for calculating transverse moment of corrugated steel box girder with single box chamber is safe and feasible.Based on the calculation method of transverse internal force of corrugated steel web box girder,this paper aims at concrete box girder to propose an improved frame method without lateral support.By establishing the deformation coordination relationship between the distortion displacement of box girder and the displacement of thin frame,an improved formula for calculating the transverse internal force of concrete box girder is derived.The rigid-supported method,the extended "TYL" frame method,the improved frame method,the non-lateral-supported frame method,the improved non-lateral-supported method and the finite element method are used to calculate the transverse moment of the key points.The results show that the improved non-lateral-supported frame method is safe and feasible,and the transverse moment value at every key point has a certain safety reserve.Especially at the corner of the bottom plate,the safety reserve of the transverse moment value is more obvious.It is unreasonable to calculate the transverse moment at every key point only by rigid supported method.In particular,the transverse moment values at corner points of the bottom plate even show positive and negative sign changes.If the transverse moment values obtained by rigid supported method are used to replace the actual transverse moment values,the corresponding correction coefficients must be introduced.By changing the angle of web,the load position,the thickness of roof,the thickness of web,the thickness of bottom plate,the width of roof and the width of bottom plate,The transverse internal moment of the corner points of two roof plates and web plates and the load action points which are obtained only under rigid-supported and under the improved non-lateral-supported frame method are analyzed.The correction coefficient η is defined as the ratio of the transverse moment value obtained by the rigid-supported method and the improved non-lateral-supported frame method.The change law of the correction coefficient ηis analyzed when the parameters change.