Which of the following is correct expression to compute design bending strength of a laterally unsupported beam?
Where fbd = design bending compressive stress,
βb = Ze/Zp, Ze = Elastic section modulus and Zp = Plastic section modulus
1
Md = βbZpfbd
2
Md = Zpfbd
3
Md = βbfbd/Zp
4
Md = βbZp/fbd