Rack Upright Frame Capacity and Unbraced Length
Compares frame load against its rating and shows the Euler buckling load at the entered beam spacing beside the load...
Example
You enter
- Beam spacing / unbraced length (in) 48
- Column moment of inertia (in^4) 0.6
- Effective length factor K 1
- Loaded beam levels 3
- Load per level (lb) 5000
- Rated frame capacity at that spacing (lb) 24000
You get
- Load per column 7500 lb (frame 15000 lb)
- Load per frame (lb) 15000
- Against the rated capacity 63% used, 9000 lb remaining
- Euler load at the entered spacing 74536 lb
- Euler load with one level removed 18634 lb at 96 in unbraced
- Removed capacity loss (%) 75
Details, formula, and sources
Compares frame load against its rating and shows the Euler buckling load at the entered beam spacing beside the load with one level removed. Doubling the unbraced length quarters the capacity with nothing visible changing. ANSI MH16.1 requires tested capacities, and damage is repaired or replaced rather than derated.
P_cr = pi^2 E I / (K L)^2 with E = 29,000,000 psi over the unbraced length set by the beam spacing; load per column = loaded levels x load per level / 2.
ANSI MH16.1 Design, Testing and Utilization of Industrial Steel Storage Racks, which requires TESTED capacities for perforated cold-formed columns and requires damaged members be unloaded and repaired or replaced.
The Euler relation is public; ANSI MH16.1 itself is a purchased standard.
Estimate. AHJ and licensed professional govern.
Field names used by the API: beam_spacing_in, column_moment_of_inertia_in4, effective_length_factor, loaded_levels, load_per_level_lb, rated_frame_capacity_lb, load_per_column_lb, load_per_frame_lb, utilization_pct, euler_capacity_lb, euler_capacity_level_removed_lb, removed_capacity_loss_pct
- Frame rating stated AT a beam spacing; it is not a property of the frame alonerack manufacturer
- Damage not a derate -- the standard requires unloading and repair or replacement, not a reduction factorANSI MH16.1