Light steel structure portal frame workshop the roof truss top chords usually used the Angle steel ,down chords and web members used angle steel or round steel bar , the design used for span ≤18m ,distance of column :4—6m ,equip lifting capacity ≤ 5ton over head crane industry workshop and span ≤18m roof structure of roof structure of civic building ,
The purlin of single story door type steel frame can divided into solid-web and lattice type ,when the span of purlin less than 9m , should priority to choose solid-web purlin, the purlin of steel structure workshop belong to bidirectional bending member ,when analysis internal force should along the cross section of two centroid axis direction to calculating the bending moment ,
Single Story portal frame roof truss steel structure workshop design points of wall purlin , bracing structure as follows :
- The wall purlin of single story door type steel workshop general used cold bend C section steel or Z section steel , the purlin of single story steel workshop under the self weight ,wall materials and the action of horizontal wind load is also bidirectional bending member.
- The wall purlin of door type steel workshop should design in same distance , on the top , bottom and top and bottom of window hole should put one row purlin , In order to reduce the vertical deflection of the wall purlin under the vertical loading could put rod on wall purlin and put batter rod on top of purlin to transmit the power to frame column .
- The wall purlin of door type steel workshop could make as simple supported beam that across one column spacing or continuous beam that across one column spacing ,door type frame structure of the cross bracing and flexible tie bar can design according to the rod , non-cross-bracing compression bar and rigid tie bar can design according rod .
- Door type steel workshop building oblique beam lateral horizontal bracing on internal force, according to the vertical wind load is calculated based on horizontal truss supporting the pillars, and included in the support to reduce the calculation length effect to the oblique beam and bear force, for cross rod bearing support is not included in the loading .
- Door type steel workshop building internal force of column cross bracing , should be based on the vertical column suffered wind load is calculated based on the vertical cantilever truss supported in the column foot, and included in the bracing of column to reduce calculation length and should bear the force, to cross the stress of the supporting rod can be not calculated loading. When in the same column with multi-channel bracing between pillars, longitudinal force can be evenly distributed between the bracing .