October 18, 2021
How To Buy a Metal Building
This is Part 1 of a multi-part series on deciphering the anchor bolt plan you will receive from Heritage when you order your custom-designed steel building. While it is likely that you will not be pouring your own concrete, a basic understanding of how to read these plans can potentially save you costly and time-consuming mistakes from mis-placed bolts. Please refer your concrete company to this page, or directly to your project consultant, if they have any questions about the plans or bolt placement.
Heritage does not supply anchor bolts. When your building is delivered, you will ideally have your foundation already poured and cured so that erection can begin immediately. Since the bolts are part of the foundation construction, it is the customer’s responsibility to purchase the proper quantity and sizes of bolts. Heritage does not recommend drilling expansion bolts into an already poured foundation; the best way to ensure maximum structural integrity of your building is to place the bolts as directed into the wet concrete and let it cure around them.
Note: An anchor bolt plan is not a foundation design. It is provided to show detailed placement of the bolts on which your columns will rest.
In the drawings you receive, there will be three pages pertaining to anchor bolts. You should provide copies of those pages to your concrete company so they can use them as a map to place the bolts when pouring your foundation.
Part 1 covers page one of the three pages, shown here in its entirety:
The Anchor Bolt Summary tells you the quantity of anchor bolts you will need in the various diameters required for your building. It also tells you for what part of the building the bolts will be used.
The Jamb and Endwall bolts are the same – they are just broken out by placement. In the example above you can see that you will need a total of thirty-two 5/8” diameter F1554 bolts.
For the framed openings on this sample building, you can see that you will need twenty-four 3/4” diameter F1554 bolts. The frame bolts have an X through them, which is carried over on the diagram page to provide a visual cue as to which bolts go where.
The bolt projection is listed in the far right column. Bolt projection is important, as it accounts for the thickness of the baseplate that will be placed onto the bolt and the nut that will be used to secure the column and baseplate to the foundation. When the nuts are tightened, they should not be flush with the top of the bolt – it is recommended that at least 1-2 threads are showing above the nut. The 5/8” bolts in the sample building require a 2” projection, while the 3/4” bolts require a 2 ½” projection.
Walk doors are self-framing, so they do not require framed openings to be built into the design of the building. As such, the anchor bolt quantity and locations are not included in these plans. You will, however, need to place anchor bolts for the doors when you are placing the rest. Most walk doors will need four 1/2” diameter bolts per door, with a 2” projection. Talk to your project consultant or third-party manufacturer to receive plans for your chosen walk doors.
Walk doors are field-located. This means you can place a walk door almost anywhere on a wall by simply using nibblers to cut out an opening in your paneling, then anchoring the frame to the foundation and fastening the wall panel to the frame.
Note: As mentioned above, walk doors can be placed almost anywhere. The exception is in a bay that has been designed to have cable bracing. As such, it is important to decide where your walk doors will be located during the design process, so your project consultant can make sure to place necessary cable bracing in a different bay.
On the diagram page, your building will be shown in a grid format like the one above. The letters indicate column placement on the endwalls, and are referred to as Column Lines. The numbers indicate column placement for the sidewalls, and are referred to as Frame Lines.
The Endwall Column section of the summary page shows a detailed breakout of which bolts will be placed at the intersections of the endwalls. In this sample building, for example, two 5/8” bolts will be located at 1D, four 5/8” bolts will be located at 5B, and so on. The baseplate and column that will be fitted onto all of these bolts will be 7 x 8 x 1/4” in size.
The Rigid Frame section of the summary page shows a detailed breakout of which bolts will be placed for the columns between the endwalls, at the sidewalls. There are three frame lines for this sample building; however, the quantity is only listed once for frame line 2. It will need to be multiplied by three for the other two frame lines. So you can see from the example that four 3/4” bolts will be located at 2D, 2A, 3D, 3A, 4D and 4A. A total of 24 bolts will house six 6 x 10 ½ x 3/8” baseplates.
The remainder of the information on the summary page pertains to the building’s reactions. This information is what your foundation engineer will need to properly design your piers and footing; is not pertinent to determining the number of anchor bolts needed.
Part 2 of this series will be available soon, and will discuss deciphering the diagram page.