Unistrut P3840 - Hinged Seismic Retrofit Brace Fitting (for Strut)


Unistrut P3840 - Hinged Seismic Retrofit Brace Fitting (for Strut)

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Item Code:P3840050EG
Hinged Rigid Seismic Brace Fitting - Retrofit, Strut Brace P3845 is an adjustable angle retrofit fitting for use primarily with seismic braces. This fitting can be used to attach a strut brace to a trapeze or other strut connection.


  • This fitting is pre-approved for the below seismic loads on page 5c.3 of Unistrut's OPM-0295-13. OPM Pre-Approved - EG finish only (OPM-0295-13)
  • Use for transverse or longitudinal rigid seismic bracing
  • Design Load: 1,397 lbs at 45° (along brace axis)
  • As a retrofit fitting, this product can be used to attach a seismic brace to an existing support without the need to disassemble that support.


Seismic Design Loads

P3840 - Image 03     P3840 P3845 - Load Table
  1. Seismic Design Loads only apply to UNISTRUT brand products. Look for "UNISTRUT" on the part.
  2. Seismic Design Loads are based on FM1950-10 dynamic testing with 12 ga. channel and a safety factor of 1.5.
  3. 1/2" Unistrut Channel Nut and Cap Screw torqued to 50 ft-lbs required for installation.
  4. Reference page 5c.3 of Unistrut OPM-0295-13.

General Specifications

Standard Dimensions (Unless Shown Otherwise on Drawing):

  • Hole Diameter:  9/16"  (14mm)
  • Hole Spacing (From End):  13/16"  (21mm)
  • Hole Spacing (On-Center):  1 7/8"  (48mm)
  • Width:  1 5/8"  (41mm)
  • Thickness:
    • 1/4"  (6.4mm) with steel meeting or exceeding ASTM A1011 SS GR 33, or
    • 0.220" (5.6mm) with steel meeting or exceeding ASTM A1011 HSLAS GR 45


  • When used for mechanical supports, load capacities of brackets and fittings should be in compliance with the American Standard Code for Pressure Piping.

Materials & Finishes

Materials & Finishes:

  • Electrogalvanized (EG):  Conforms to ASTM B633, Type III SC1 or SC3