Transverse stiffeners should be installed above the supports and in places where concentrated forces are transmitted.
The installation of these ribs can be limited to without checking the calculation of local stability, if the wall thickness of the bent beam is not less than Vso K where h is the design height of the wall, which is equal for a welded structure to the full height of the wall, and with a riveted structure - the distance between the risks of the belt corners closest to the axis of the wall.
If the wall thickness of carbon steel is less than 1koh, in addition to the above stiffeners, additional intermediate transverse stiffeners are installed.
The maximum permissible distances between adjacent transverse stiffeners are specified by the local stability calculation.
High beams with thin walls are also reinforced with longitudinal stiffeners. When installing one longitudinal rib, its distance from the compressed belt is recommended to be set equal to (0.20—0.25) h.
In the case of installing two or three longitudinal stiffeners, the first rib is recommended to be placed at a distance (0.15-0.20) / i, and the second rib at a distance (0.40-0.50) * h from the compressed belt. The third rib is usually placed in the tensile zone of the wall to increase the critical shear stress.
The width of the protruding part of a paired symmetric rib in the presence of some transverse stiffeners must be at least b 40 mm on each side of the wall, where h is in mm.
When the ribs are located on one side of the wall, the moment of inertia is calculated relative to the axis coinciding with the wall face closest to the rib. The rib thickness must be at least Vis of the width of the protrusion and at least 10 mm.
If there is no horizontal sheet in the upper chord of the riveted beam and the bridge beams are supported on this chord, the protruding parts of the transverse stiffeners must be fitted to the horizontal flanges of the flanges.