TinnerFlow
Traditional Hangers & Supports ยท Supports & Hangers

Seismic braced trapeze

Seismic restraint

ConnectionSupport method only
SupportRod/strut/cable seismic bracing

Before you start

  • Confirm the approved support detail, actual duct weight, support spacing, attachment substrate, hardware size, corrosion protection, and any insulation, seismic, vibration, or rooftop requirements before installation.
  • Confirm the engineered seismic-bracing detail, gravity trapeze, brace type, anchor, substrate, brace angle, compression strut, load path, and clearance requirements.
  • Keep gravity support and seismic restraint functions separate.
  • Inspect rods, strut, cables, anchors, clamps, and structural attachment points.

Tools and materials

Approved gravity trapeze, engineered seismic cables or struts, anchors and attachment hardware, compression strut where required, installation tools, level, laser, tape, lift, and approved touch-up materials.

Lay it out

  1. Install and level the gravity trapeze first.
  2. Mark transverse and longitudinal brace locations from the engineered detail.
  3. Coordinate brace paths with access, lights, piping, and equipment service.

Set and support it

  1. Complete the gravity support before tensioning braces.
  2. Install only approved structural attachments.
  3. Keep brace contact from damaging duct or insulation.

Make the connection

  1. 1

    Verify the brace location, angle, anchor, and attachment point.

  2. 2

    Install the structural anchors and brace hardware.

  3. 3

    Connect transverse and longitudinal braces as shown.

  4. 4

    Install a compression strut where required.

  5. 5

    Adjust or tension braces without moving the duct out of line.

  6. 6

    Lock and inspect all hardware.

  7. 7

    Document concealed attachments before closure.

Check the install

  • Brace geometry matches the engineered detail.
  • Gravity supports continue to carry dead load.
  • Anchors and structural attachments are complete.
  • The duct remains level and centered.
  • Braces do not block access or damage the system.

Common mistakes

  • Using seismic cables as gravity supports.
  • Tensioning braces until the trapeze shifts.
  • Attaching to unapproved structure.
  • Relocating a brace without engineering approval.

Stop and ask

Stop if brace design, attachment substrate, anchor, load path, angle, compression strut, or field relocation is not approved.