3 Things to Know About How Expansion Joints Work on Bridges

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(Newswire.net — April 11, 2023) — Have you ever driven over a bridge and noticed small gaps between certain road sections? These are called expansion joints, which are an integral part of bridge construction that helps protect it from damage caused by changes in temperature. But what do they do? The following are three things to know about how bridge expansion joints work.

1. Provide a Space for Movement

As temperatures change, bridges may expand or contract due to their material composition. Expansion joints provide a space that accommodates this movement and prevents the bridge from cracking or becoming unstable. They are typically composed of steel plates with rubber seals, which allow them to compress and expand in response to temperature changes without compromising structural integrity.

Many bridges must also accommodate movement from traffic and other outside forces, such as earthquakes. Expansion joints provide space for these movements as well. When properly installed, expansion joints can reduce the stress on the bridge and improve its longevity. Finally, expansion joints also reduce noise from traffic by acting as a buffer between adjacent sections of the bridge.

2. Need Regular Maintenance and Repair

Despite their durability, expansion joints need regular maintenance and repair to function efficiently. Over time, the rubber seals may become brittle due to exposure to ultraviolet light or extreme temperatures, or they may need to be replaced if they become too worn. Steel plates may also corrode or bend over time due to wear and tear caused by traffic movements.

Additionally, the joint expansion gap may need to be adjusted to accommodate temperature or traffic load changes. This is why engineers must routinely inspect and maintain bridges with expansion joints. This ensures the bridge remains safe and can accommodate movement without causing excess strain.

3. May Vary in Size Depending on Their Purpose

The size of an expansion joint can vary greatly depending on its purpose and the type of bridge it’s installed in. Smaller bridges typically require smaller expansion joints that are only a few inches wide, while larger bridges may require larger joints that span up to several feet.

In addition, different types of movement may require different types of expansion joints. For example, seismically active areas may need extra flexibility expansion joints to handle strong vibrations from earthquakes or other seismic activity. Additionally, some bridges need expansion joints that cover multiple lanes to accommodate high levels of traffic flow.

Lastly, some bridges may require special expansion joints to absorb shock from vehicles traveling at high speeds. With so many expansion joints, bridge engineers must choose the right type for each application to ensure safety and performance.

Expansion joints are an important part of bridge construction and maintenance, and engineers need to understand how they work to ensure the safety of drivers and pedestrians. By understanding the factors that go into designing and installing expansion joints, engineers can ensure that bridges remain safe and secure despite changes in temperature or traffic conditions. Whether it’s a concrete arch or suspension bridge, take a closer look next time you step onto one to appreciate all the elements that go into its stability and longevity.