Answers from the Engineer: Fabric Building Foundations

In this blog series "Answers from the Engineer", our panel of fabric structure experts answers questions from industry insiders submitted during a recent webinar regarding fabric structures. Today’s questions address foundations.

Q. How do the foundation costs of fabric buildings compare to traditional pre-engineered metal buildings (PEMB)? Higher uplifts? Are lateral thrust forces due to rigid frame action the same as with traditional PEMB?

Yes, you will find that because we are using loads driven by ASCE7 for load determination that the horizontal, vertical and uplift vertical forces will be nearly identical in fabric building foundations to PEMB foundations.

Q. Are foundations typically larger for fabric buildings versus PEMB?

There is no real difference in magnitude. You will find that because we are using loads driven by ASCE7 for load determination that the horizontal, vertical and uplift vertical forces will be nearly identical.

Q. Can Legacy design a foundation?

Currently we provide about 50% of the foundations with our buildings. Many owners like to keep the whole design in one contract to streamline their permit process, turning in stamped foundation drawings with the stamped building drawings. Other clients have local engineers they use on projects, so we give them our preliminary reactions and work with the foundation engineer to make sure the anchor bolt layouts work with their foundation.

Q. What are some of the factors that affect foundations?

The cost of a foundation is dependent on the building’s size and location. Other factors that influence the foundation design include:

• Environmental factors such as snow, wind, and seismic
• Soil conditions
• Water table
• Frost depth
• Weight of the building
• Collateral loads (e.g. conveyors, mezzanines, HVAC systems)

A thorough evaluation of all these factors is needed to assess and design the best foundation option for each building. Because ground compressibility can lead to excessive settlement differentials, similar or even identical buildings may require completely different foundations at different sites. That’s why we encourage our clients to consult with a foundation engineer on every project. Their expertise will ensure that you are making good decisions about your building.

What questions do you have? Contact us to arrange a consultation and find the answers.