Study On The Effective Length Of Columns In The Staggered Truss Structures

The column's effective length of steel staggered truss systems was studied based on the assumption of rigid diaphragm of floor including vierendeel truss and composite truss arrangement.The paper simplified the bracing from the truss as lateral bracing spring and modifying the rotating restraint spring of the chord , to set up the model for analyzing. The paper gains the columns' buckling equation and calculate the columns' effective length, providing corresponding calculating formula.For composite staggered truss structures, the truss was simplified as two stories with lateral bracing spring model. Through theoretical analysis the columns' buckling equation was arrive at. Since the equation is too complex to use in practice design. The effective formulas of length factor was obtained.Several examples were calculated through the above formulas, the coefficients of effective length of the column were obtained, and were compared with those from finite analysis. The results showed that they agree well.