What Is a Trench Plate?

Trenches are temporary and are usually backfilled with soil after construction. While a project is underway, however, it’s possible to cover a trench so that traffic may continue using the road as normal. This is done with a trench plate.


Trench plates are large, flat sheets of steel that sit over a trench, acting as a type of “lid.” They are also used along trench boxes during excavation for utility construction and repair. The purpose of a trench plate is to provide a temporary surface for traffic to pass over while construction is underway.


Trench Plate Safety

In order to utilize trench plates in the safest and most effective manner, it’s important to choose the right plate dimensions for each specific trench. A good rule of thumb is for traffic traveling 44 mph or less, there should be a 12” overlap of the steel plate on either side of the trench. For traffic traveling 45 mph or more, the overlap should be at least 24” on either side of the trench. __This overlap ensures that if the trench plate shifts, the hole will remain firmly covered. __


As with all road projects, a structural engineer should be consulted and full site surveys conducted before construction begins. A trench plate’s proper size, thickness and deployment plan will need to be formally assessed by a qualified professional to meet all state and local requirements for bridging an excavation site.

Thickness, Threading, and Materials of a Trench Plate

Trench plates are made of steel that is commonly at least one inch thick. They sometimes feature hardened threaded weld nuts and engineered lifting devices (such as lifting rings) for easy installation. Many plates come with a skid-resistant texture that’s applied to the surface to prevent vehicles from sliding on the steel, especially in wet conditions.


Though trench plates are often 1-inch tall, their thickness will depend on the speed of traffic moving over the plate. Speeds above 45 miles per hour may require taller plates, such as a 1.25-inch or 1.5-inch plate thickness.


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Common Trench Plate Sizes

Some common sizes for trench plates that are one inch thick include: 4×4, 4×6, 4×8, 4×10, 4×12, 4×16, 5×8, 5×10, 5×12, 5×16, 6×8, 6×10, 6×12, 6×16, 8×10, 8×12, 8×16, 8×20.

How Trench Plates Are Manufactured

Trench plates are manufactured in steel mills and are made by hot rolling. To do this, a steel slab is heated to 1,700 degrees Fahrenheit and passed through a series of rollers. Each set of rollers makes the slab thinner until the desired thickness is achieved. Once the steel is the correct thickness, the plate is cooled to room temperature and cut to size or rolled into large coils.


Hot rolled steel is the cheapest sheet steel available. However, cold rolled steel is another option. Cold rolled steel is created when a steel sheet that has previously been hot rolled is run through a second series of rollers without the addition of heat to create an even thinner sheet of steel. Steel must be hot rolled before it can be cold rolled.

Purchasing New vs. Used Trench Plates

For buyers looking to purchase trench plates, there are two main options: new trench plates or used/surplus trench plates.


If you purchase new, you’ll know the quality upfront; new trench plates have never been used before, meaning the structural integrity is known to be solid and there will be no wear and tear setbacks once construction begins. The downside is that new trench plates cost much more than used plates, and delivery could take longer since the plates are often coming from the manufacturer.


If you purchase used plates, you’ll pay less, often for a very similar product. Furthermore, used steel plates are ready for immediate use since they do not need to be manufactured; they sometimes come with mill certifications; and they enable high quality results despite prior use due to the longevity of steel. The downside to purchasing used trench plates is that they often contain wear and tear and they can’t be custom made to fit an exact project’s needs.


In many cases, used and surplus trench plates are just as effective as new plates and can be used successfully in their place. The decision depends on the project specifications and availability at the time of purchase!

Features to Consider when Choosing Trench Plates

When choosing trench plates for a project, there are several features to consider, including:

  • The plate size and size of area to be covered

  • Thickness recommendations

  • Load bearing features

  • The use of fixing and machining processes

  • Anti-skid treatments

  • Safe handling and installation options

  • Plate details such as edges, ramps and chamfering

  • Transportation options


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Buy and Sell with Eiffel Trading

Did you know that Eiffel Trading’s marketplace boasts a wide variety of new and used steel options? From used steel trench plates, to new steel trench plates, to used sheet pile, and everything in between… we have what you need for your next project! In addition to steel products, we also sell used and surplus HDPE pipe, used and surplus traffic barrier (like jersey barrier!) and more.


All of our listings are constantly being updated, but if you don’t see what you’re looking for, create a wanted listing.


Ready to sell your used heavy equipment or construction material? List your products today on Eiffel Trading’s online marketplace.


If you have any questions or would like additional information, please call us at 1-800-541-7998 or email sales@eiffeltrading.com.