I would like to expand upon my reply and comment about other suggestions
(1) Placing the pipe under a building is not optimal, but may be the lessor of all evils and most economical solution.
(2) The main considerations are leak proofing the pipe, replacing the pipe in the future and structual soundness. The commonly accepted solution is to sleeve the pipe, like in a "jack & bore" crossing. A 24" RCP pipe would propaply require a 36" mild steel sleeve because a minimum of 6" clearance around the bells is needed and a common standard size is usually cheapest. The sleeve prevents leaks under the building by moving them out side, usually 5' minimum beytound the footer, it also enables replacement of the carrier pipe and it usually is structually sound enough. You may want to check the loading at the footers and possible use a lintel over the pipe.
(3) Place the minimum size required by good design. Face it, storm water systems will always fail because a bigger than designed storm will sometimes occur. Just make sure that failure will not cause problematic flooding and remember that everywhere else will be flooded at the same time due to the downpour.
(4) Encasing the carrier pipe in concrete is not an optimum solution. It does not allow for pipe replacement and unless steel is used at all joints, it wil not prevet leakage. If any leakage should occur, the building will be endangered.
(5) If a larger pipe is needed in the future, then it will be "jack & bored" Clifford H Laubstein
FL Certified PE #58662