Point Loadings Explained Simply for Spider MEWPs

What Is a Point Load?

Welcome to SpiderMEWP.com! We want to make sure you're safe and understand how your awesome spider lift works, especially when using its outriggers. Let's talk about something called point loading.

Imagine standing on soft ground. If you stand on flat shoes, your weight is spread out a bit. But if you stand on one heel, all your weight is focused on that tiny point – that's a point load! Another way to think about it is a concentrated load, where the force is acting at a single spot.

Point Loads and Your Spider MEWP's Outriggers

Your spider MEWP and truck-mounted cherry picker often use outriggers (sometimes called stabilisers) to keep the machine stable when you're working at height. These outriggers have feet that touch the ground. When the MEWP is set up, the entire weight of the machine plus you and your equipment in the platform is supported by these outrigger feet.

Each outrigger foot becomes a point where a large amount of force is pushed down onto the ground or whatever surface you're working on. Think back to the heel example – each outrigger is like a very heavy heel pushing down. The outrigger foot typically applies a vertical load to the ground.

Why Point Loads Matter for Safety

Understanding point loads is really important for a few reasons:

• Ground Stability: The ground or surface underneath your outriggers needs to be strong enough to handle these concentrated forces. If the ground is too soft or weak, the outrigger could sink in, making the MEWP unstable and potentially dangerous.
• Preventing Damage: Indoors, especially on surfaces like tile, these point loads can be enough to crack or damage the floor. The force impact of the MEWP's support points can affect the ground surface material itself.
• Safe Operation: If the point loads aren't properly managed, it could lead to the MEWP tipping over, which is a serious hazard.

Using Spreader Mats to Help

To deal with these point loads, we often use spreader mats under the outrigger feet. These mats are designed to distribute this concentrated load over a larger area. Imagine putting a flat piece of wood under that heel – suddenly, the pressure is spread out!

The Temporary Works Forum (TWf) guidance highlights that the main goal of a suitable outrigger mat is to spread the maximum outrigger load to the minimum required bearing area. So, instead of all the force being on one small point, it's spread across the area of the spreader mat, reducing the pressure on the ground.

However, even with spreader mats, the load is still initially concentrated at the point of contact between the outrigger leg and the mat. The mat then works to spread that load outwards.

Key Things to Remember

• Outriggers create point loads: The feet of your MEWP's outriggers focus the machine's weight onto small areas.
• Check the ground: Always make sure the ground or surface can support these concentrated loads.
• Use spreader mats: These help to spread the load over a wider area, reducing pressure and increasing stability.
• Mat Size Matters: Simply having a mat isn't enough; it needs to be the right size and strength for the load. The outrigger mat has to be large enough to satisfy the minimum required bearing area.
• Get Expert Advice: If you're unsure about the ground conditions or the right spreader mats to use, always seek advice from a competent person. Mayon Machinery can provide measurements needed to calculate the impact on floor surfaces. The Temporary Works Forum (TWf) also offers guidance on assessing and managing outrigger loading.