Research On Calculation Method Of The Transverse Distribution Of Multi Room Wide Box Girder

As the span of a bridge expands triggered by increasingly wider roads, single-boxmulti-chamber girder bridge becomes more widely used in the city among all the smalland medium-span bridges. Characterized by a smaller spacing between web plates anda larger number of chambers, the bridge is more complex in mechanical properties andcharacteristics of the structure and there is no specific calculation method forsingle-box multi-chamber wide box girder. Grillage method and transverse distributionmethod are broadly used in multi-chamber wide box girder currently. Researches showtransverse distribution method would result in large errors though grillage methodapplies well to multi-chamber wide box girder. Therefore, it is necessary to improvethe present calculation method for the load transverse distribution to make it suitablefor the transverse distribution calculation of single-box multi-chamber wide box girder.Firstly, torsion force characteristics of the multi-chamber wide box girder areanalyzed with the general finite element software. Take the single-box multi-chambercantilever wide box girders with various chambers and width-span ratios for example,entity finite element models under torsional load and eccentric load are constructedrespectively, with which the shear flow distribution of the chamber and the transversedistribution of the vertical displacement in the cross section are compared and analyzed.Results show that shear flow distribution under torsional load is in general accord withthat of the single-box single-chamber box girder or the common multi-chamber boxgirder with a relatively small width-span ratio and shear flow distribution undereccentric load primarily consists of torsional shear flow and bending shear flow. As aresult, calculation and analysis under eccentric load is the superposition of overallvertical displacement and overall torsion.Secondly, based on the rigid beam method for the transverse distributioncoefficient of multi-beam bridge, the research proposes the correction rigid beammethod applicable to multi-chamber wide box girder. The box girder is cut along theroof and floor between the web plates into I beam components and the incision isexerted by redundant forces which can be figured out by the establishment of forceequation and the solution of matrix equation. As a result of the complex solvingprocess of rigid beam method, the redundant solver program is designed in the researchand the calculation steps and essentials to revise rigid beam method are presented. Finally, finite entity element model is established through compute instance toverify the revised rigid beam method and applicability and accuracy of the method arealso examined. It can be found out that this method, boasting good practical values, notonly facilitates the calculation of single-box multi-chamber wide box girder, but alsoprovides basis for further studies.