Beams: Meaning, Types & Capacity Calculation

Introduction

Beams are basic supporting components in warehouse racking systems. Their bearing capacity determines the overall strength and safety of the structure.

Calculating the correct beam capacity is essential to check if the racking system can sustain the intended loads without failure. Whether dealing with uniformly distributed loads or point loads, the capacity of a beam must be accurately determined to prevent damage, accidents, and operational disruptions.

This guide will walk through the meaning, types, and step-by-step calculation of beam capacity to help warehouse operators make informed decisions in selecting the right industrial racking system.

Types of Beams in Warehouse Racking Systems

Understanding the different types of beams used in warehouse racking systems is essential for selecting the right one based on your unique needs. Here are some of the most commonly used beam types:

• Selective Beams: These beams are the most common in single or double-deep racking systems. They may come with or without holes to allow for the installation of crossbars. Their design allows them to handle a wide range of pallet loads and provide easy access to inventory.
• Pushback Beams: These beams are used in pushback racking systems, and they always have pre-drilled holes for the installation of pushback rails and pallet stops. They are typically employed in higher-density storage solutions.
• Reverse Beams: These beams feature a distinctive design where the toes are welded towards the aisle, providing a structural advantage in certain aisle configurations.
• Cross Aisle Tie (C.A.T.) Beams: These beams join two rows of racking across the aisle, providing additional stabilization for single rows of selective racking. They are useful in preventing racks from swaying.
• Gusset Beams: Reinforced with gussets (triangular plates) welded onto the beam clip and underside, these beams offer higher moment capacity and strength. They are ideal for applications where heavier loads are expected.
• Pallet Flow Beams: These specialized beams are designed for pallet flow systems. They come with holes punched for mounting angles, which attach the pallet flow tracks, ensuring smooth movement of pallets within the system.

Key Factors Affecting Beam Capacity

Several factors influence the load-bearing capacity of a beam. Some of the key considerations include:

• Material Strength: The strength and composition of the steel or other material used in the beam will determine how much weight it can safely support.
• Load Distribution: The way loads are distributed across the beam—whether evenly or in concentrated areas—affects the calculation of beam capacity.
• Environmental Conditions: Factors such as temperature, humidity, and potential corrosion can weaken a beam over time, reducing its overall capacity.
• Beam Length and Cross-Sectional Area: Longer beams or those with smaller cross-sectional areas tend to have reduced capacity and require additional support or reinforcement to bear heavier loads.

Steps for Calculating Beam Capacity

To calculate the capacity of a beam in a warehouse racking system, follow these essential steps:

 1. Identify Load Type: Determine whether the load is uniformly distributed across the beam or concentrated at specific points. This is critical for selecting the appropriate calculation method.

 2.Determine the Span: Measure the distance between the supports of the beam. In a typical racking system, beams are either single or double deep, which affects the load distribution.

 3.Calculate the Factored Load: Apply a load factor based on the type of load (dead load or live load). For example, for a dead load of 1000 lbs and a live load of 1000 lbs, use the governing load combination: 1.2×dead load+1.6×live load1.2 \times \text{dead load} + 1.6 \times \text{live load}1.2×dead load+1.6×live load.

 4. Moment and Shear Calculations: Use appropriate equations from steel design manuals to calculate the maximum shear (V) and moment (M_max) the beam will experience. These are critical values for determining whether the beam can support the intended load.

 5. Select a Suitable Beam Section: Consult tables from steel design manuals, such as the AISC Steel Manual, to select an appropriate beam section. Look for a beam with a moment capacity that exceeds the calculated moment in the system.

 6. Check for Lateral Torsional Buckling: Ensure that the beam's unbraced length is adequate to prevent lateral torsional buckling, which occurs when the beam twists or bends out of the plane of the load. This requires checking the compactness of the beam's flanges and web.

 7. Perform Shear Capacity Check: Finally, perform a shear strength check by calculating the shear capacity of the beam. Ensure that the beam's shear capacity exceeds the maximum applied shear force.

Selecting the Right Beam for Your Racking System

When choosing a beam for your warehouse racking system, consider the following:

• Load Requirements: How much weight does the beam need to support? Beams for heavier loads will require larger cross-sections or reinforcement through gussets.
• Spacing: The distance between beams and the height of the rack can affect the load distribution and the capacity needed for each beam.
• Beam Material: Steel is the most common material for beams in warehouse racking systems, but the specific grade and type of steel can impact strength and capacity.

Consider More: Lateral Torsional Buckling

Lateral torsional buckling is a phenomenon that can significantly reduce a beam’s capacity, especially in long-span beams that are not adequately braced. To prevent this, ensure the beam has enough bracing or compactness in its flanges and web.

One practical approach is to reduce the unbraced length or increase the beam’s depth. This is particularly important for beams supporting high or unevenly distributed loads.

Final Words

In summary, after knowing the types of beams available, the factors that influence their capacity, and the steps involved in the calculation, you can make a better choice in selecting the right racking system.

But we don't mean to underestimate the complexity of the warehouse status quo, if you have any problem with warehouse design/schedule, don't hesitate to contact us now, our team of experts is willing to help you frame the best storage solution