... structure,applicated widely in bridge ,workshope ,building.....An I-beam, also known as H-beam, W ... -beam (for "wide flange"), rolled steel joist (RSJ), or double-T (especially in Polish, Spanish and German), is a ... that the I-shaped section is a very efficient form for carrying both ... -section has a reduced capacity in the transverse direction, and is also inefficient in carrying torsion, ...