Static field route #19328

What do I do when a duct run only has side-to-side seismic bracing?

Seismic Bracing, Sway Control & Structural Coordination⚠️ CHECK BEFORE YOU FIXField answer expansion

📖 Verified core answer

A long duct run usually needs restraint for more than one direction. Check the seismic layout and add the missing brace direction by approved detail.

Open in Field Rescue Open category

Field verification checklist

Identify which braces are lateral vs longitudinal.
Check run length and brace intervals against approved seismic detail.
Look for straight runs with no end-to-end restraint.
Coordinate conflicts before adding braces.
Document corrected brace layout for inspection.

Ask foreman

This duct run has lateral braces but I do not see longitudinal restraint. I checked the run direction and seismic detail. Do you want longitudinal braces added before inspection?

Text to foreman

Route options

AMake the field correction only if it is within your assignment and the approved method.

BHold and document the condition if the fix affects support load path, structural steel, seismic restraint, life safety, another trade, or inspection.

CBring the foreman/detailer the location, what you checked, and what decision you need before loading, cover, startup, or rework.

Do not do this

Do not assume one brace direction controls every direction of earthquake movement.

Why this matters

Missing brace direction can fail inspection and let the whole duct run move in a seismic event.

Final verification

Use this as field training guidance. Final direction still comes from the foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, structural/seismic detail, and AHJ/code requirements.

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