A circular concrete shaft liner with a Young’s modulus of 3.4 million psi, Poisson’s ratio of 0.25, unconfined compressive strength 3,500 psi and tensile strength 350 psi is considered for control of water pressure (190 psi) at a depth of 3,750 ft. Inside shaft diameter after lining must be 18 ft. Find the liner thickness necessary to achieve a safety factor of 2.5. What outside shaft diameter is indicated?