Abstract：
The midst pavilions in the urban practice area of EXPO 2010 consist of several reconstructed factory buildings. Every hall has novel architectural form and a unique structure style. Through transforming the longitudinal structure for resistance to lateral force, the intercolumn braces were canceled, the requirement for the large space was meet. In some pavilions, the new structure was isolated from the original structure. The V-shape steel frame was applied for the new one. The calculation results shows the significance torsion effect of the V-shape steel frame. The installation of the longitudinal intercolumn braces reduced the torsion effect in the seismic calculation, the calculation results meet the code requirement. Based on the torsion theory of the closed thin-walled bar, the calculation method of restrained torsion of V-sharp columns was analyse.
