Proven Reliability of Chicago Clamp Systems: Load Capacities & Safety

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Independent Lab Testing & Load Capacity Tables for Clamp Systems

Each Chicago Clamp System® has been designed, and then rigorously tested by an independent engineering lab, to provide a product on which you can depend. Load tables derived by calculation and testing are conveniently organized in table form.

Testing apparatus for Chicago Clamp Systems, featuring a mechanical load testing setup with steel beams and clamps, demonstrating rigorous engineering evaluation for reliability and safety in construction applications.
Man inspecting a clamp system during rigorous testing in an engineering lab, emphasizing safety and reliability of Chicago Clamp products.

Suspension Clamp System
Live Load Capacity (pounds) vs. Span of Back-to-Back Angles 1-11

Size of Each of an Angle Pair
Longest angle leg is vertical		 Span (feet)
2 3 4 5 6 7 8 9 10 11 12 13 14 15
2" x 2" x 3/16" 1,690 1,123 821 635 511 – – – – – – – – –
2" x 2" x 1/4" 2,000 1,459 1,088 856 693 569 – – – – – – – –
2 1/2" x 2" x 3/16" 2,000 1,707 1,237 956 769 635 536 – – – – – – –
2 1/2" x 2" x 1/4" 2,000 2,000 1,691 1,313 1,061 882 748 643 528 – – – – –
3" x 2" x 3/16" 2,000 2,000 1,645 1,270 1,020 842 708 604 521 – – – – –
3" x 2" x 1/4" 2,000 2,000 2,000 1,791 1,446 1,200 1,061 873 759 665 587 520 – –
3 1/2" x 2 1/2" x 1/4" 2,000 2,000 2,000 2,000 2,000 1,682 1,428 1,232 1,074 945 837 746 667 599
4" x 3" x 1/4" 2,000 2,000 2,000 2,000 2,000 2,000 1,873 1,618 1,414 1,246 1,106 988 886 798
5" x 3" x 1/4" 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 1,932 1,700 1,507 1,344 1,203 1,081

Table Notes 1-11

  1. Two Spanning Angles required per Suspension Clamp System, purchase though your local vendor.
  2. Angles are back-to-back, but spaced apart by Suspension Clamps.
  3. Allowable net load, per pair, may be located anywhere along the span. Weight of angles has been accounted for.
  4. Angle dimensions are listed “Vertical Leg” x “Horizontal Leg” x “Thickness”.
  5. No values below 500 lbs. are listed. Allowable loads have been limited to 2,000 lbs. maximum.
  6. Allowable loads are based on 36 ksi minimum yield steel and the AISC specifications.
  7. A single load equal to the tabulated capacity or multiple loads with a sum equal to the tabulated capacity is allowable.
  8. Live Load Capacities based on Safety Factor of 2.0.
  9. Loads in bold (528) are governed by deflection limit of Span/240; (e.g., 0.500″ for 10′ span).
  10. Tabulated values are based upon the additional bracing provided by Suspension Clamp System.
  11. Tabulated loads based on vertical loading only.

Joist Grip Framing Clamp System
Allowable Load (pounds) vs. Span a-h

Tube Size (inches) Load Type Span (feet)
3 4 5 6 7 8 9 10
HSS 4" x 2" x 1/8" concentrated 2,000 2,000 2,000 2,000 1,801 1,572 1,318 1,067
uniform 2,000 2,000 2,000 2,000 2,000 2,000 2,000 1,708
HSS 4" x 2" x 3/16" concentrated 2,000 2,000 2,000 2,000 2,000 2,000 1,820 1,474
uniform 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000

Table Notes a-h

  1. Allowable concentrated load at middle of span. Allowable loads are net (weight of tube has been accounted for).
  2. Multiple loads, that are symmetrically placed and whose total equals the tabulated value, may be used.
  3. The reaction to each clamp bracket must be limited to a net value of the clamp’s charted capacity.
  4. Allowable loads have been limited to 2,000 lbs maximum.
  5. Allowable loads are based on 46 ksi minimum yield steel (A500, Gr. B), the AISC specification and a safety factor of 2.0.
  6. Loads in bold (1,067) are governed by applied-load deflection limit of Span / 240; (e.g., 0.50" for 10′ span).
  7. Tube’s 4" dimension is vertical. Span is horizontal.
  8. Tube weights: 4.75 lbs/ft for 1/8" wall, and 6.87 lbs/ft for 3/16" wall. Weights and thicknesses are nominal.

Tube Framing Clamp System
Live Load Capacity (pounds)

Component Capacities Download Positive Uplift Negative
Allowable Load (pounds)
Joist Grip End Clamp 1,000 1,000
T-Bracket 1,000 1,000
InLine End Clamp 1,000 1,000
Girder Clamp 1,000 –
Cross Support Bracket 1,000 –

Edge Tubes
Allowable Span vs. Load & Load-Type a-g

Size of Rectangular Tube (inches); minor axis bending (a-g) Max Load = 500 lbs. Max Load = 1,000 lbs.
Concentrated Uniform Concentrated Uniform
(in.) (ft. & in.) (in.) (ft. & in.) (in.) (ft. & in.) (in.) (ft. & in.)
HSS 3" x 1.5" x 1/8" 64 5′ – 4" 81 6′ – 9" 45 3′ – 9" 57 4′ – 9"
HSS 3" x 1.5" x 3/16" 73 6′ – 1" 93 7′ – 9" 52 4′ – 4" 65 5′ – 5"
HSS 3" x 1.5" x 1/4" 79 6′ – 7" 100 8′ – 4" 56 4′ – 8" 70 5′ – 10"

Table Notes a-g

  1. Short dimension of tube cross-section is vertical, parallel to load (minor axis bending).
  2. Allowable, net concentrated load, per tube, may be located anywhere in the span. Weight of tube has been accounted for.
  3. Allowable uniform load is the net loading on the tube. Weight of tube has been accounted for.
  4. allowable loads are based on 46 ksi minimum yield steel (ASTM A 500, Gr. B) and the AISC specification.
  5. All net (applied) loads are governed by deflection limit of Span / 240; (e.g., 0.250" for 5′ span)
  6. Tube-wall thicknesses are nominal. Minimum is 0.93 times nominal, per 2005 AISC specification.
  7. Allowable loads ("max" loads) arebased on a safety factor of 2.0.