Which of the following is NOT a functional requirement of a girder ?
- AStrength to carry bending moment
- BVertical stiffness to satisfy any deflection limitation
- CStrength to carry shear i.e. adequate web area
- DStiffness to reduce the buckling or post-buckling strength of the webCorrect
Solution
Concept
Design requirements of plate girders
Step-by-step solution
1. A girder must carry bending, shear, and satisfy deflection limits. 2. It needs stiffness so that the web resists buckling and develops post-buckling strength. 3. A requirement to "reduce" the buckling or post-buckling strength is not a requirement at all.
Explanation
Stiffeners are provided to INCREASE the web's resistance to buckling, not to reduce it.
Why the other options are wrong
(a), (b) and (c) are standard functional requirements.
Shortcut
Stiffeners increase, not reduce, web buckling strength.
Correct answer: D) Stiffness to reduce the buckling or post-buckling strength of the web