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Assemble Structural Steel

1 min read

Table of Contents

Start With a Strong Frame #

Your metal building’s strength begins with its structural steel frame. This section walks through the safe and efficient assembly of columns, rafters, girts, and bracing—including key alignment and safety tips to avoid costly errors or collapses.

⚠️ Before beginning, confirm all anchor bolts are placed correctly using your final “For Construction” drawings.

Tool Checklist #

For a standard two-person crew, SNAP recommends:

  • 4,000–6,000 lb telescoping forklift
  • Bull pins, ratchets, impact drivers
  • 2′ and 4′ levels
  • Spud and crescent wrenches
  • Safety harnesses, hard hats, gloves
  • Rope and choker straps
  • Screw guns with magnetized sockets
  • Drift pins and hammers

All tools must be OSHA-approved and jobsite-ready.

Sidewall Frame Assembly (Start Here) #

Steps: #

  1. Lay out rigid sidewall columns, girts, and eave struts
  2. Raise sidewall columns and snugly attach them to anchor bolts
  3. Hand-tighten girts to columns
  4. Install eave struts and hand-tighten
  5. Add temporary bracing for safety before lifting rafters

🖼️ Diagram: Sidewall Column and Girt Setup #

Fig. 8 – Girts overlap and alternate direction. Match punch marks and align large flanges.

Roof Rafters and Cable Bracing #

Once sidewalls are braced, move to roof structure:

  1. Assemble rafters on the ground
  2. Lift and secure central rafter first
  3. Guy-off with ropes or cables for stability
  4. Install purlins and cable bracing bay-by-bay
  5. Only tighten bolts once the structure is plumbed

🖼️ Diagram: Rafter and Cable Bracing Installation #

Fig. 9 – Cables, purlins, and clip fasteners shown with correct overlaps and bolt methods.

Plumbing, Squaring, and Securing the Frame #

Once the main frame is erected:

  • Use a level and string line to plumb the center bay
  • Use diagonal measurements to square frames and bays
  • Use the “turn-of-the-nut” method to tighten all structural bolts per AISC specs
  • Add cable bracing and cross-check for movement before continuing

🖼️ Diagram: Squaring Frame Bays #

Fig. 11 – Ensure A = C and B = D; measure diagonals before final tightening.

Endwalls and Framed Openings #

After bays are complete:

  1. Raise and secure endwall columns
  2. Install rafters and remaining girts
  3. Install door and window framed openings
  4. Double-check alignment and spacing
  5. Only tighten after endwalls are fully squared

🛠️ Reminder: Do not modify rigid frame members. Field modifications void structural warranties.

Final Bolt Inspection #

Before moving to panels:

  • Tighten all bolts using “turn-of-the-nut” method
  • Touch up scratched primer
  • Ensure all cables are snug but not over-tensioned
  • Remove any temporary bracing only when frame is fully stable

📘 Need a Visual Guide for Your Project? #

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