Question

A plate girder is used when

(a) span is large and loads are heavy

(b) span is small and loads are heavy

(c) span is small and loads are light

(d) span is large and loads are light

The question was asked in an interview for internship.

I want to ask this question from Plate Girders & General Considerations topic in chapter Gantry Girders, Design of Plate Girders & Industrial Buildings of Design of Steel Structures

Answer 1

Right answer is (a) span is large and loads are heavy

The best I can explain: A plate girder is deep flexural member used to carry loads that cannot be economically carried by rolled beams. When load is heavier and span is also large, there are three options : i) two or more I0sections, connected appropriately (ii) plate girder (iii)truss girder. Of the above alternatives, first is uneconomical. So, plate girder or truss girder can be used.  Plate girder is used since cost of fabrication of truss girder is high.