Selecting the right pedestrian bridge for your needs involves many decisions about structure, design, and maintenance needs. Most people don’t have much experience when it comes to designing, sourcing, and installing these bridges. It can be hard to know if you’re making the right choices. In this blog, we’ll go over the key considerations to keep in mind when designing fiber-reinforced polymer (FRP) pedestrian bridges.
Different Types of Pedestrian Bridges
Footbridges, boardwalks, and other pedestrian walkways are common features in parks, municipalities, golf courses, or other types of land development projects. They can be purely functional but many also add an element of beauty. In any setting, the first consideration the bridge type, which falls into three primary categories:
Truss bridges. In use for over 50 years, these “workhorse” bridges are an optimum solution for spans of 50 to 150 feet. They are also a good choice where there are hydrology concerns, such as a flood plain site. Historically, these structures are painted or use galvanized steel with wood or concrete decks. In the last 20 years weathering steel or fiberglass truss construction with fiberglass decks has become common because these materials offer superior corrosion resistance, especially in freshwater locations.
Beam bridges. These simple bridge structures consist of structural beams, a deck, and a railing. They work very well for spans of less than 50 feet and typically utilize a solid surface deck design (such as concrete or fiberglass) to protect the structural beams from corrosion.
Specialty bridges. It can be fun to think about designing a custom specialty bridge and the options are truly endless. However, that flexibility comes with a premium cost, and the reality is truss and beam bridges tend to be more cost-effective.
Bridge Design Considerations that Count
An experienced bridge designer or contractor is a great resource for your project. As you talk about your needs and goals with them, keep these important considerations in mind:
- Aesthetics. You probably have an idea of the visual effect you want from your bridge. Fortunately, there are usually many ways to achieve a signature look at different price points.
- Elevation. Truss bridges can offer advantages over beam bridges in a flood plain setting because there is little structure below the deck surface. Truss structures also incorporate the railing into the structural truss since it extends above the deck.
- Bridge Span. The span of the bridge may limit the types of options available. In general, truss or suspension bridges are better for long spans between 50 and 100 feet, and beam bridges are best for shorter spans that are less than 50 feet.
- Maintenance/Initial Cost. Initial cost and maintenance cost go hand in hand. Long-lived materials, such as FRP and weathering steel, may initially cost more than wood construction; however, because they are virtually maintenance free, upkeep labor and costs are greatly reduced over the lifetime of the structure. You’ll want to look at this trade-off based on your budget and resources.
- Usage. It can be helpful to anticipate all the potential uses of the bridge, such as vehicle or equestrian traffic, snow removal, snowmobile or ATV usage, as well as overall pedestrian traffic. Knowing what usage patterns will have the greatest effect on the decking material helps determine its expected lifespan.
At Axcess, LLC, we know planning a new pedestrian bridge project is exciting but not always simple or clear-cut. We can help you from design to construction and at every step in between – please contact us today to learn more!
