Plate Girders - 1 - Civil Engineering (CE) MCQ

The depth of plate girder is adjusted to get the minimum self-weight of the girder and that depth is called economical depth of plate girder,

σ_tw = Allowable bending stress in tension

Vertical stiffeners are provided at the spacing of 0.33 of to 1.5 d where d is the distance between the flanges ignoring fillets and if horizontal stiffeners are also provided d is the maximum clear depth of the web. Spacing can be reduced near the supports where the shear force is large compared to the centre of the girder.

As per clause 6.7.4.6 of IS: 800-1984, intermediate horizontal stiffeners not subjected to external loads shall'be connected to web by rivets or welds, so as to withstand a shearing force, between each component of the stiffener and the web of not less than,
125t² / h kN/m

Unequal flange angles with long horizontal legs are provided to serve the following purposes:
1. To increase the moment of inertia of the section, and
2. A large length is available for making the connection with the flange plate.