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Cable Guards High Load Bearing & Tear Strength Qualities

02/01/2022

Load Bearing

All Elasco products have high load-bearing resistance thanks to our solid-cast polyurethane, although the exact measurement differs slightly from product to product.

Elasco products can bear the load whether its a spiked high heel or rolling semi-tractor
Elasco products can bear the load whether its a spiked high heel or rolling semi-tractor.

Because cable guards and dropovers are subjected to human as well as vehicular traffic, they must be able to support a well-placed spiked high heel as well as a rolling semi-tractor and trailer and accommodate the unique forces and pressures applied by each.

Although at a glance, a high heel and a wheel couldn’t be further apart, for that brief moment in time where they’re pressing down on the cable ramp they are both nothing more than a load that the ramp has to be able to handle.

Additionally, the rolling movement and force of a wheel presents a unique loading and unloading of forces, as well as the reciprocal force of expelling the guard from beneath the wheel.

The loads for both examples are measured on a similar using a static PSI (pounds per square inch) scale, however, the movement and forces behind the rolling wheel are quite different.

The moment in time where the full load of the truck tire or high heel is present atop the guard can be measured and a value determined wherein the flex (give) or deflection of the guard can be observed and measured.

To find out the exact load bearing capabilities of each of our products, please contact us.

Tear Strength (or Resistance)

Polyurethane (PU) is widely preferred as the material of choice in applications where a high degree of tear strength is important. PU is known for high tear resistance (initiation) as well as a high resistance to tear propagation, or the expansion of a tear. Tear strength is often included in the topics of tensile strength, modulus and elongation as all use the ASTM D 412 method. Testing method ASTM D 624, however, is the preferred method for measuring tear strength.

Tear strength is closely related to abrasion resistance and the correlation between tear strength and abrasion resistance is high. Applications where cutting blades are used to cut materials like carbon fiber for instance are appropriate uses for PU. The cutting of the material on top of a PU surface allows the blade to penetrate the material and although the PU is scored the forces required by the operator aren’t so strong as to destroy the PU material.

Why high tear strength is important for Elasco cable ramps

Material with low tear resistance are more likely to damage with repeated abrasion. Cable ramps experience repeated abrasion along the top side every time vehicle tires drive over the ramp. They’re also subjected to abrasion along the bottom side. When vehicles drive over, the cable ramp is repeatedly being pushed over the ground surface. Rough surfaces like gravel or stone will create more abrasion and more risk of damage.

Source

Cutnell, John D., & Kenneth W. Johnson. Physics. 4th ed. New York: Wiley, 1998. 338.

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