Question

Which of the following is true regarding plastic design methods?

(a) design needs to satisfy elastic strain compatibility conditions

(b) different factor of safety for all parts of the structure

(c) saving of material over elastic methods resulting in lighter structures

(d) design is effected by temperature changes, settlement of support, etc

I had been asked this question in an interview for job.

Origin of the question is General Requirements for Plastic Design and Plastic Hinge topic in section Plastic and Local Buckling Behaviour of Steel of Design of Steel Structures

Answer 1

Right option is (c) saving of material over elastic methods resulting in lighter structures

Easy explanation: The following are the advantages of plastic design methods: (i) realisation of uniform and realistic factor of safety for all parts of the structure , (ii)simplified analytical procedure and rapidity of obtaining moments since no need to satisfy elastic strain compatibility conditions, (iii) no effect due to temperature changes, settlement of support, etc, (iv) saving of material over elastic methods resulting in lighter structures.