Thankyou for your reply.I have some more doubte regarding design of box Bridges.
Iam analysing box using elastic beam method for Longitudinal forces . But where i shall consider Torsion, Distortion and Shear lag Effects.
In elastic analysis we are taking torsional stiffness, is it not enough to take moments. Shall i add any additional moments
And for Shear lag effect, i have read somewhere effective thickness shall be considred at utimate check not in moment calculation.
Please give me details, how shall i proceed.