I suggest hiring Real Log Homes or Timberpeg out of NH. They are a good firm and it sounds like they may have a bit more background in the subject than you.
you can also contact the "International Log Builders Association" in Lumby, BC (250-547-8776). They have a lot of good information to include log span tables and construction techniques.
As for the lateral design though, I would contact a local structural engineer who has dealt with these structures. They are a very different animal structurally in lateral performance. I have designed many over the years.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
I've been engineering various types of log homes for about 15 years. There are many methods of fastening the logs together each of which requires slightly different analysis. The ILBA does issue beam span tables but don't tell you what they are based on. Here are some articles and helps that have come out in the last few years. They are helpful in figuring out how to analyze. There are also some other threads on this forum about log home and log shear wall design.
The ICC 400-2007 is the code for prescriptive design and gives TPI timber values for whole logs which up until now were hard to get. Most grading societies don't give values for whole round logs. The restrictions on seismic, wind and snow make ICC 400 not valid is about 1/3 of the US where you would normally build a log home or cabin.
Remember you can't use the entire round section for analyzing round beams in bending or compression. NDS 2005 for round piles lets you use the properties of a square with the same crossectional area of the enclosed circle. ASTM D3957 requires you to use the properties of a square that can be fully incribed inside the shape of the log. The ASTM spec is quoted in ICC 400 and 2009 IBC but ends up being very conservative (50% for Moment of Inertia and Section Modulous of round section h=b=0.707*dia). I normally use the NDS which gives about 75% of the section modulous of the full circle (h=d=0.86*dia).
The ILBA in conjunction with other groups use to offer a week long class in Fort Collins and Estes Park Colorado on design and engineering log homes. I haven't seen it advertised for several years.
If you have a specific style log home and specific questions the forum can probably answer them.
ICC 400-2007 2007 Standard on the Design and Construction of Log Structures
