Struts: Critical to Keeping your Pallet Racks Straight and Strong

The overall integrity of a racking system is a sum of the strength of its individual components, including the humble strut. Struts are the bracing between the columns of the frame. Though they seem tiny and insignificant, they play a crucial role in the structure of racking systems often overlooked at significant risk. A pallet rack frame structure is supported by struts, columns, beams, and footplates. Two columns are connected by horizontal and diagonal struts and anchored to the floor with footplates. Based on the design of the racking system, the struts can either be welded or bolted to the columns. Let’s learn how to keep your struts in perfect working order, and keep your warehouse safe and efficient.

How do struts strengthen a rack?

The uprights are responsible for transferring the weight of the goods to the ground, providing vertical strength. The uprights support the downforce of the weight of the system and the inventory on the shelves. However, if these uprights deviate from their ideal position, less than ½ inch in 10’ out of plumb, it can result in severe consequences. The struts are precisely engineered to provide rigidity to keep the system from moving side-to-side or forward-to-back. Struts are designed to keep the frame posts in perfect plumb. Struts are key engineering components that can prevent a catastrophic warehouse collapse, a domino effect of frames failing. This domino effect is seen in many of the warehouse collapse videos that are available online. Struts, therefore, are mission-critical to your racking system’s functional integrity. Every tiny detail of the strut structure is significant. The attachment method of welding or bolting, the gauge of steel, the pattern of horizontals and diagonals must conform to strict engineering standards. 

How can a strut get damaged?

Struts are vulnerable components in your racking system that can be easily damaged. Most struts are made of lighter gauge steel than the uprights and are in conspicuous locations. These factors make them easily prone to impact damage from forklifts, pallets, and product. Additionally, less visual factors like environmental factors and improper loading can slowly damage struts as well. However, knowing what causes damage is half the battle. Here are the major factors to watch out for that cause damage. 

Rust and corrosion

Corrosion is a metal’s worst enemy and diminishes its strength and structural integrity. Like every metallic component, struts are also prone to damage from environmental factors like moisture and chemicals. Corrosion is more likely to occur in harsh industrial environments with plenty of exposure to chemicals and water. If your business operates under such conditions, inspect corrosion damage more often than usual. Your inspections should look for servere rust through and the beginnings of rust where paint has failed. Be sure not to dismiss rust as merely surface level. There can be more damage inside of the strut that is not visible on the outside. Qualified inspectors can quantify the damage more precisely. 

Forklift and pallet strikes

Damage due to forklift impacts is one of the most common causes of damage to a pallet racking system. The majority of racking system collapses also result from forklift strikes. Alongside damaging other system components, an impact from a forklift can immediately damage and weaken the struts. Additionally, pallet and inventory strikes could also result in strut damage and damage its structural integrity. To counter this problem, handle the loading and unloading with extreme care and use experienced operators. In addition, there must be constant vigilance to not come in contact with the struts. 

Loose bolts and broken welds

Bolting and welding are the two most common methods of attaching different components of the system. However, these bolts might loosen with time, and the welds might break under heavy pressure or impact. Take care of loose bolts and broken welds immediately. If they’re left unattended, the system’s ability to carry loads and prevent frame failure degrades. 

Missing components

Pieces of hardware, called fasteners, are used to attach the struts on any pallet rack. These components provide the connection points needed to affix the struts to the uprights. Fasteners can be bolts or miscellaneous clips. Welds are also used to connect struts to the upright frame. The lack of or damage of these components can degrade the structural integrity of the rack and the system as well. Therefore, take care to make sure the connectors are present and are functional. 

Avoid Open Panels on Pallet Racks

Racking frames with both horizontal and diagonal struts are the common optimum solution for most pallet racking systems. These patterns and frequencies were explicitly designed by the original engineer of your racking system for your specific warehouse use pattern. When frames are missing engineer-designed diagonal struts, they create what’s called an open panel. Open panels are generally defined as no diagonal strut between two horizontal struts. Diagonal struts are responsible for significantly increasing the directional rigidity of frames that horizontals cannot do alone. Moreover, they are also responsible for boosting protection against the forces of irregular loads. 

Avoid open panels. If you have an open panel in your racking system frames, this is likely due to damage or removal of a part and not a part of the original engineering. Take note of all open panels and consult your original as-built plans. 

Irregular Loads

Although struts improve the protection against damage from irregular loads, they don’t make the system completely immune to it. Uneven distribution of load on the racks might exceed the tolerance of your struts. All loading should conform with the racking load capacity charts and placards. When the weight of improper loading acts upon one side of the horizontal strut, damage can occur. That side bears more pressure than the other, making it vulnerable to stress. Always stay within the load distribution designations for each bay. Always load according to engineering directions for your system. Failure to do this can overload the struts and cause racking failure. 

How to inspect the struts for damage?

Warehouse pallet rack inspections should always be done by a trained certified professional. Mac Rak trained technicians can perform these official inspections. However, at times an initial observation needs to be made by a non-certified inspector. Mac Rak has an online inspection tool and printed inspection guides for this purpose. If you see any damage in your preliminary review of your racking system, contact Mac Rak immediately to set up a full formal inspection to diagnose and repair your pallet racks. In most cases, a single point of damage doesn’t result in system failure, but collective failure may occur when the accumulation of unrepaired damage points is combined. Therefore, it is important to inspect any damage and take immediate action. 

What to Look for when surveying your struts

1. Deflection and dents, and severed/torn steel
2. Missing parts, or fasteners, broken or compromised welds, or open panels
3. Rust, corrosion, missing paint

Look for lost or missing fasteners, connecting components, and broken welds. Professional help is highly recommended while dealing with such issues. Report any open panels as well. 

Check regularly for signs of corrosion and rust. Even slight corrosion should be addressed before leading to a more significant issue. If corrosion is present, take the necessary repair measures to remedy the problems, including replacing the components.

While making initial observations for strut damage in a racking system, you must be looking for any signs of deflection, dents, or severed/torn steel. If any horizontal or diagonal struts are deflected by more than 0.5” in either plane, the issue must be addressed immediately. Additionally, if the entire frame is out of plumb by more than 0.5” in 10’-0”, in either plane, there might be an issue with your struts as well. 

Upon impacts by forklifts, pallets, and other pieces of equipment, an immediate preliminary inspection must be done to make sure that no damage has occurred. Routine inspection should also look for unreported impact damage done by forklifts, pallets, or products. 

How to Repair Pallet Rack Struts

First, trained technicians should always do repairs that maintain the original engineering specifications of your racking systems. Second, replace all damaged or missing struts with parts that are identical or have superior engineering specifications. Mac Rak has engineered pallet rack repair kits for struts and upright frame components. Mac Rak also has complete engineered repair kits with welded strut components custom manufactured to your engineering specifications. We have many different engineered designs and endless custom solutions that will work with any racking type, brand, or punch style. Our engineered pallet rack kits are designed for three categories, super heavy-duty, heavy-duty, and standard-duty. In addition, we engineer all our parts according to ANSI/RMI 16.1 standards. Those standards state that all parts must meet or exceed original engineering specifications and should be inspected and installed by a trained professional. Contact Mac Rak to schedule an inspection, repair, or simply ask a question. We are committed to the safety and efficiency of your pallet racking systems in your warehouse. 

The Mac Rak Warehouse Safety Guide

This article is a part of the Mac Rak Warehouse Safety Guide. This guide is a comprehensive reference tool for warehouse managers and maintenance professionals, and engineers. It is designed to give you easy access to the data you need to make decisions and run your warehouse efficiently and safely. 

The Mac Rak Advantage

Mac Rak is the only American-owned and 100% American-made engineered pallet rack repair and protective guarding solution provider in North America. We are also the proud founding members of the RMI rack repair committee, which guarantees you that all our products meet the highest industry engineering standards available.

We look forward to being of service to you and your company.

Shawn MacDonald
President / CEO