METAL BUILDINGS

PRE-ENGINEERED METAL BUILDINGS FOR DUMMIES

A bit of information shared by Tom Waldren through his trials and tribulations over the last 2 decades.

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In a means to educate all on this type of building, I have put together this document to assist all of us in planning, designing and building a Pre-Engineered Metal Building (PEMB) system, erase myths, and make us all smarter than the average General Contractor, in the eyes of an Owner. Whether you are a Business Development Manager, Estimator, Project Engineer or Project Manager, my hope is that everyone develops a general knowledge of this type of structure, thinking about the needs of an Owner, and not make some of the mistakes that I have made over the years.

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So, what is the difference between a conventional steel building, and a pre-engineered metal building?

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ENGINEERING! In a nutshell, when an Engineer designs conventional steel, he takes all of the load data, calculates the most stressful load encountered, and then specifies a beam or column capable of withstanding that load, making the entire flange and web thickness the depth required for that load.

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With a PEMB, the Engineer looks at where the loads apply, i.e. kickout at the base plate, or column to beam connection at the haunch, and designs that section accordingly. Then he looks at the midpoints, where the loading is less critical, and designs that section accordingly. What you end up with are flanges that may be ½” thick near the base and haunch, then reduces thickness down to 3/8” for a portion, with maybe ¼” at the center. He then does the same with the webs. Flanges on the inner face may be thinner than the outside face section at times. Then, all the multi-sectional pieces of flanges and webs are cut out of plate steel, set in their beam line equipment, with flanges run vertically, web horizontal, on the jig.

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This jig is run then run through an auto welder, which welds the top of the web member to the sides of the flanges, continuously, from the top. On the underside, all that is required is about a 1-2” stitch weld every 12-18” o.c. to attach the web to the flanges. The final result is a savings in the amount of steel required to make the columns and rafter sections. Less steel equals less dollars, and in the Industry, it’s all about tonnage---less is more for the Owner.