How to design a box culvert bridge having dimensions $15$ ft x $15$ ft $.$ Culvert is subjected to a dead load of $420$Ib$/$ft$^2$ and a live load of H$-20$Aashto standards trackedvehicle.type of soil ; clay sandy loam,asphalt asphalt $22$ kN$/$m$^3,$ Assume the unit weight of soil is $130$ lb$/$ft$^3.$ angle of repose of soil is $30\backslash$deg $.$ The road width is $18$ ft with a $1$ ft wide footpath on both sides. Use f$\text{'}$c $27\mathrm{.}6$ MPa concreteand Fy $=60$ MPa steel. Please $,$Calculate Design Loads:

Determine Soil Load:

Structural Analysis:

Select Materials and Dimensions:

Check for Limit States:

Reinforcement Design:

Footpath and Road Width:

Review and Iterate:

Please show calculations and not use IA to solve