Find the maximum possible $($steady state$)$ thaw depth beneath a garage with a floor on the ground at Deadhorse Alaska. Mean annual permafrost temperature is $20F$ and mean annual floor temperature in a garage is $50F.$ Thermal conductivity of the permafrost soil is $1\mathrm{.}2BT\frac{U}{f}t**hr**F,$ and thermal conductivity of thawed soil is $0\mathrm{.}9BT\frac{U}{f}t**hr**F.$ Length to width ratio of the building is greater than $4$ and its width is $40ft.$