Calculation of Torsion Center Position of Single Box Multi-Room Box Girder

Based on the structural characteristics of thin-walled box girder structure,the explicit formula for the computation of the torsion center position is presented.Through the parameter analysis with the formula,the formula is not only suit for double room girder bridges,but also suit for single room girder cross section,and rectangle cross section.On the condition of changing some parameters,the formula is also suit for some open cross section,such as  type section,groove section,T type section,and so on.