If Md is the design bending strength of a section, then what is the requirement for the factored design moment M at any section in a beam due to external actions under limit state design?

The strength and size specification of a butt weld is primary specified by its:

As per IS 800, the maximum bending moment for the design of purlins can be taken as (where W is the total distributed load including wind load on purlins and L is the effective span/centre distance of supports):