How do I design a concrete pad on grade for at the base of metal stairs. The metal stairs will be bolted into the concrete pad. How do I determine the thickness of the pad needed and how large and how do I account for the bolts into the concrete. Also, the load wont be completely vertical. It is on more of a 45 degree angle. I have attached a photo of a similar pad but just don't know where to start to design one. Thanks