The expansion or wedge bolt securing a rack base plate to the concrete warehouse floor.
Detailed Definition
A rack anchor bolt fastens the base plate of a rack upright to the concrete slab. The most common types are wedge anchors and other post-installed mechanical anchors set in holes drilled through the base plate holes. Anchors keep uprights from sliding or tipping when they are struck by a forklift, when loads are placed unevenly, and in seismic areas. The number, size and embedment depth come from the rack design, which follows the RMI specification ANSI MH16.1 and local building codes.
How anchors are specified
The rack engineer selects the anchor type, diameter, embedment depth and number per base plate based on the loads the rack must resist. Those loads include forces from pallet placement, horizontal loads, and, in seismic zones, earthquake forces. The anchor's capacity also depends on the concrete: slab thickness, strength, and distance from slab edges, joints and cracks. Taller or seismically designed racks often need more anchors and larger base plates.
Installation points to check
- Use the anchor model and size called for in the rack drawings, not a substitute chosen on site.
- Drill to the specified diameter and depth, clean the hole, and tighten to the anchor maker's instructions.
- Use shims, not stacked washers, to level uprights, within the limits the rack maker allows.
- Keep required distances from slab edges and joints.
Inspection and damage
During routine rack inspections, look for missing, loose or sheared anchors, anchors pulled up out of the slab, and cracked concrete around the base plate. A forklift strike that bends an upright can also loosen its anchors. Damaged anchors should be replaced following the rack maker's or engineer's guidance, and column protectors can reduce repeat impacts.
Related Glossary Terms
Frequently Asked Questions
Do pallet racks have to be anchored to the floor?
In general, yes. The RMI specification used for US steel storage rack design calls for rack columns to be anchored, and building codes and permitting authorities usually require it, especially in seismic regions. Some local codes add their own rules. Treat the rack manufacturer's drawings and your local building department as the authority, and do not remove anchors when moving or reconfiguring rack.
Can I reuse anchor bolts when relocating rack?
Mechanical anchors such as wedge anchors are usually not reused once removed, because their expansion parts deform when first set. Relocated rack should be anchored with new anchors that match the design, set into new holes in sound concrete. Follow the anchor maker's and rack maker's instructions and have the new layout checked against the original design loads.