Frame Building Expo Summary

I attended the 2007 Frame Building Expo last week in Indianapolis. It is hard to absorb all of the information and networking opportunities available at such an event, but I'd like to share some of my highlights as they affect the projects for my business and my clients in the months and years ahead.

On the first day, Prof. Gary Anderson, P.E., PhD from South Dakota State University presented a thorough discussion of the effect that soil backfill has on the stiffness of our embedded post buildings. Gary presented a lot of technical information on how the soil stiffness can be modeled more precisely. If it helps present a visual picture, I typically model the soil for embedded posts as a whole bunch of springs resisting lateral movement of the post with the stiffness of the springs getting higher the further below grade you go. Gary's presentation was aimed at more accurate predictions of spring stiffness modeling in various soil embedment conditions.

Because this whole analysis can affect the amount of stress in the columns and the location of the maximum stress, the modeling that Gary presented is quite important to the basic question of "What size columns do I need?" and it's one reason I have been reluctant to assist others in developing column sizing charts... there are many variables which can have a large impact on the calculated stresses. This is just one of those variables (diaphragm stiffness is another!)

On Thursday, Prof. David Bohnhoff from the University of Wisconsin gave a presentation on Post Frame Foundation Options. He presented the basic factors of deciding whether or not to embed the posts in the ground, a decision that seems to be trending toward "not to embed" in my opinion. He discussed the options in terms of structural considerations, construction impacts, and other issues to consider.

Dave also presented some great information on Grade Beam Foundations, or Frost-Protected Shallow Foundations (FPSF). These foundations are not designed to extend to frost depth but to be protected from the effects of Frost by other means. You need three things for frost heave 1) Water, 2) Freezing Temperatures, and 3) Soils conducive to ice lense formation. Removing one or more of these factors from the soil beneath the footings reduces the frost heave potential. Dave ended his presentation with a discussion of Thermal Envelope Requirements and, as with all of his presentations, great graphical displays accompanied all of the information. (Dave has a wealth of great Post Frame information on his website.)

Later on Thurday, Charles Carter of the American Institute of Steel Construction (AISC) discussed Steel Panel Braced Frames which will be discussed in a soon to be published design guide (#20) by the AISC. These strong shear wall segments could serve as a custom made alternative to products such as the Simpson Strong Wall system. These could lend themselves to use in Post Frame projects where we have a lot of endwall forces to transfer from roof to foundation with very little endwall to do it in, such as Airplane Hangars or any storage buildings with large endwall openings.

For additional summary information from the Expo, including the many exhibitors with popular and new products, you should check out the Rural Builder Buzz blog by Scott Tappa. He gets around and knows a lot about many issues in the industry that I don't have the time to keep up with.

In future posts at Structural Integrity, I will try to go into more detail about these engineering topics presented here as well as others that I think are relevant. I'll also try to use this forum to answer some of the questions that come up from clients as a way to share information with more people who may have similar questions. I hope you find this useful.

Have a great day!