Raised floor foundation "help"

[HawkRidgeLodge]

A bit of background information. I had planned to put a Sobon Shed style frame on a rock foundation. My measurements are 30x36. I originally planned to have a 14ft wide frame with 8ft additions on each side. I have instead decided to go with a 12 wide frame in the center and conventional framing on each side. So I will have a 12x30 timber framed center section and stick framed outer sections. This is mostly due to material availability.  So with all that said I have dug the dry footings and was planning to lay a grade beam 10 inches thick. I then plan to place peirs on the grade beam and in the center of the crawlspace. Please look at the attached sketch and give me you feedback or concerns. The peirs will have 4inch ledges for beams to set on to add additional support to floor joist. I was planning to put a 2x10 raised floor on this and just block below the post and add strapping or plates for sill to post attachment.  

 

 

 

 

 

[Don P]

I finally had my morning eyes on and could read the upside down sketch, only the 2 lower pics show up for me.

What you have sketched is really a strip footing rather than a grade beam. The bottom of it should be below your local frost depth. There should be a continuous perimeter foundation wall which I believe you are describing in slipform. Code says a rubblestone foundation should be a minimum of 16" thick. Just personal preference but rather than full slipform I've built an inside form and left the outside open. Then mix both pea gravel concrete in one wheelbarrow and mortar in another. Quickly lay up the visible outer face with mortar and backfill behind it to the form with concrete. Laying some rebar in as you go is not a bad thing at all.

From what I'm imperfectly understanding the rest sounds ok, do check your girder sizes and spans. Good tables are here starting at R602.7;
https://codes.iccsafe.org/content/VRC2015P2/chapter-6-wall-construction