Design Of Steel Structures | Plate Girder

Design of Plate Girders * Plate girder is a built up I-section beam with two flange plates connected to a web plate of required depth. * A plate girders need stiffeners to avoid buckling of web. Types of stiffeners used are: (a) Transverse (vertical stiffeners) (i) Bearing stiffeners (ii) Intermediate stiffeners. (b) Longitudinal (horizontal) Stiffeners * If only one horizontal stiffener is provided, it will be at a depth 0.2d from compression flange. If another horizontal stiffener is to be provided it will be at mid-depth of web. * Self-weight of plate girder: w = kN/m where w = factored self-weight W = total factored load on the girder. * Economical depth: It is given by where k = , M = factored maximum moment and fy = yield strength. * Another practical guideline for selecting depth of plate girder is = for girders in building = for highway bridges = for railway bridges. * Flange thickness may be found by assuming that only flanges resist moment. Hence, = M To keep the section semi...