Pallet Rack Base Plate Anchorage and Overturning
Resolves lateral force on a rack frame into overturning and resisting moments, net anchor uplift.
Example
You enter
- Frame weight including product (lb) 15000
- Frame depth (in) 42
- Top beam elevation (ft) 20
- Lateral force coefficient 0.2
- Effective height as a fraction of the frame 0.666667
- Allowable tension per anchor (lb) 1800
- Anchor holes in the base plate 2
- Allowable tension in a better slab (lb) 2800
You get
- Lateral force 3000
- Overturning moment 40,000 ft-lb
- Resisting moment from weight 15,750 ft-lb (39% of the overturning)
- Net uplift per column 6,929 lb of anchor tension
- Anchors required 4 against the holes available -- SHORT by 2
- Anchors in the better slab 3 -- still short of the plate's holes
- Arm ratio 7.61905
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
ScopeResolves lateral force on a rack frame into overturning and resisting moments, net anchor uplift, and the anchor count against the base plate's holes. The worked frame needs 4 anchors into 2 holes, and still 3 in a better slab. The anchorage question is really a question about the floor.
Formula or tableOverturning M_o = lateral force x effective height; resisting M_r = 0.6 x frame weight x half the frame depth (ANSI MH16.1 ASD uplift combination); net uplift = (M_o - M_r) / frame depth; anchors = net uplift / allowable tension per anchor, rounded up.
Source and editionANSI MH16.1, the applicable building code and its seismic provisions, and the post-installed anchor's evaluation report at the slab thickness, concrete strength, and edge distance actually present.
Free accessThe statics are public; ANSI MH16.1 and anchor evaluation reports are published by their own bodies.
What governsEstimate. AHJ and licensed professional govern.
API field namesframe_weight_lb, frame_depth_in, top_beam_height_ft, lateral_force_coefficient, effective_height_fraction, allowable_anchor_tension_lb, base_plate_holes, improved_anchor_tension_lb, lateral_force_lb, overturning_moment_ftlb, resisting_moment_ftlb, net_uplift_lb, anchors_required, anchors_required_improved, arm_ratio
- Lateral force entered as a coefficient on the frame weight acting at a fraction of the frame heightspec-v1811 screening idealisation
- Remedies a larger plate, a thicker or reinforced slab, a shallower frame, or bracing to the structure -- none is a field decisionrack design engineer