There's a pretty good chance that the bridge as-builts will include the historical soil borings. If not, go with PEinc's suggestion and add borings to the design scope. You may need to do this anyway, since historical borings may not meet modern standards. I would advise retaining a...
Drilling a new borehole probably won't take much if any additional time anyway if you are drilling in soil for the full depth, with the exception of highly overconsolidated clays. Any time savings wouldn't outweigh the risk of cross-layer contamination from mixing cuttings from different depths...
NAVFAC DM 7.2 (Foundations and Earth Structures) is useful for developing your soil loads. Goldberg's Lateral Earth Support and Underpinning comes in handy fairly often, especially for soldier pile and lagging designs.
Does anyone know of any standards related to color-coding soil types for representing subsurface profiles (for example blue for clay, yellow for sand, etc.)? I haven't had any luck finding anything. Any input would be much appreciated.
Mike
