I need structural engineer

Modular home, 27.9’x52’, 12” width wall, 3.5” brick veneer and 8” cmu block. Need footers designed and engineer approved. We have one step down at 12.61’, 16” step down, we would like to dig a lug straight down the middle of 27.9’ instead of doing individual piers. The piers will be 16”x16”, approx. 10 of them. If we just did a continuous footer throughout the whole thing we could build piers where they are needed.