Ilever Racking Systems: Heavy-Duty Cantilever Engineering & Global Procurement Guide

Ilever racking systems (widely referred to across industrial material handling as cantilever racking systems) are specialized storage architectures engineered without front vertical columns. Instead, vertical steel columns anchored to heavy-duty base plates support series of horizontal arms that project outward into the aisle.

This front-unobstructed design permits continuous, uninterrupted horizontal storage bays. Mechanically, the weight of the inventory generates an eccentric rotational bending moment ($M = P \times L_{cg}$) transferring downward through the arms into the vertical column and outward to the floor slab anchors. UNARCO RACKING designs every column-to-arm interface to resist torsional and shear loads while maintaining strict safety factors.

The choice between structural steel and roll-formed steel depends on three key parameters: load weight density, forklift operating environment, and total project lifecycle ROI:

• Specify Heavy-Duty Structural Ilever Racking: When handling heavy structural shapes, rebar bundles, bar stock, solid lumber packs, or steel coils where loads exceed 2,500 lbs per arm. Structural steel fabricated from hot-rolled I-beams offers extreme structural ductility, high impact resilience against lift truck collisions, and is mandatory for outdoor or unheated warehouse environments.
• Specify Roll-Formed Ilever Racking: For lighter-duty applications such as retail building supplies, PVC piping, conduit, aluminum trims, or furniture where arm loads range from 500 to 2,500 lbs. Roll-formed components provide greater initial cost savings and rapid adjustability.

Calculating ilever racking capacity requires rigorous application of RMI (Rack Manufacturers Institute) ANSI MH16.1 specifications. Capacity is never calculated solely by dividing total bundle weight by the number of arms. Key calculation steps include:

1. Load Distribution & Arm Quantity: The load must be supported by enough arms to prevent unacceptable material sag or localized arm overloading. A standard rigid load requires at least two arms; flexible loads (such as thin tubing or flexible plastic conduit) may require 3 to 5 arms spaced closely.
2. Center of Gravity ($L_{cg}$): Arm rated capacity is based on a Uniformly Distributed Load (UDL). If a 48-inch arm holds a load whose center of gravity sits at 24 inches, the arm supports its full rated capacity. If the load sits off-center toward the tip, effective capacity is drastically reduced by increased leverage.
3. Single-Sided Loading Factor: For double-sided columns, the upright tower must be engineered to resist full load on one side while the opposing side remains completely empty, generating the maximum possible overturning moment at the base.

Because ilever racking systems concentrate severe overturning moments at the base plate rather than purely downward compressive loads, concrete foundation requirements are significantly stricter than standard pallet racking:

Typically, a minimum slab thickness of 6 to 10 inches or more of reinforced concrete (minimum 3,000 to 4,000 PSI compressive strength) is required. Large base plates with multiple mechanical wedge anchors or structural epoxy anchors are specified. UNARCO RACKING structural engineers verify both nominal embedment (total drilled depth) and effective embedment (actual tension cone development depth) to ensure anchors cannot pull out under combined seismic and live loading conditions.

Yes. UNARCO RACKING routinely engineers and manufactures outdoor roofed shed cantilever systems. The vertical upright columns are extended upward to support structural steel roof trusses, purlins, and corrugated steel roofing, providing dry, sheltered storage for weather-sensitive lumber or steel stock.

These outdoor structures require comprehensive engineering analysis under International Building Code (IBC) and ASCE 7 parameters, factoring in site-specific basic wind speed ($V$), snow drift accumulations, exposure categories (B, C, or D), and seismic ground motions ($S_s, S_1$).

To accommodate diverse materials, UNARCO RACKING supplies engineered accessories including:

• Removable End Stops / Pipe Retainers: Vertical pins inserted into arm tips to prevent round pipes, tubes, or round bar stock from rolling off.
• Solid Steel & Wire Mesh Decking: Placed across cantilever arms to transform individual arms into continuous shelf decks for short pallets, cartons, and irregular crates.
• Axle / Spool Saddles: Curved brackets that fit onto arms to support heavy cable spools and wire reels for controlled unreeling.
• Heavy Column Protectors: Bolt-on floor deflector guards that protect upright columns from side-loader and forklift wheel impacts.

To enable UNARCO RACKING engineers to deliver an accurate, code-compliant proposal, please prepare:

1. Facility Layout: AutoCAD floor plan indicating clear ceiling height under building steel/sprinklers, column grid locations, and slab joint patterns.
2. Inventory SKU Profile: Material dimensions (Length $\times$ Depth $\times$ Height), minimum and maximum bundle weights, and material flexibility.
3. Material Handling Equipment: Type of lift truck (counterbalance, reach truck, side-loader, or multidirectional forklift), mast extended height, and required aisle operating clear width.
4. Project Zip Code / Geographic Site: Required for seismic hazard calculations and foundation verification. Direct all inquiries to [email protected].