Can a bottom flange plate be added to a beam and checked as a composite section?
When using built-up shapes as composite sections the new built up shape will need to be added to the master table and steel beam design table. When using built-up members, note the following: All of the calculations of the composite section are still based on an assumption that the shape is an I-shaped section, all of the equations used by the program for wide-flange beams were derived from that shape. If the plastic neutral axis falls down in the bottom flange or within the added shape, the results given by the program will potentially be wrong (except for the case of a plate). When the reinforcement is a plate, it is straight-forward: specify the bottom flange with a thickness of the combined flange and plate (tf’ = tf + plate thickness) and specify the width as the width that would produce the same area as the combined flange and plate (bf’ = (area of flange + area of plate) / tf’). This will give correct results, except the check for width / thickness requirements of the bottom fla
