Understanding the importance of your pedestrian bridge’s weight will help you to make well-informed decisions throughout the design process. Before you choose the bridge materials, you will need to know some more details about your project first.
The below sections will help you understand the importance of a bridge’s location, bridge materials to consider, other factors that impact a bridge’s weight, and the next steps in your bridge project.
Pedestrian Bridge Location
A bridge’s location is important in making a well-informed, cost-effective decision on bridge material. Be sure to ask yourself the following questions when reviewing bridge materials and the bridge size.
- Is the bridge location in a remote, hard-to-access space?
- Will I have easy access to the site to transport the bridge materials?
- Can the site be accessed by heavy machinery for assembling the bridge?
- Will it be easy to maintain, repair or replace the bridge in the next 20,30, 50+ years?
4 Common Pedestrian Bridge Materials
Most of a bridge’s weight is determined from the materials used to build the bridge. There are four common materials used to build pedestrian bridges.
Steel
Steel might be the most common bridge material, but it’s also the heaviest. It weighs approximately 500 pounds per cubic foot.
Aluminum
Aluminum weighs only about ⅓ of the weight of steel. It weighs approximately 169 pounds per cubic foot.
Fiber Reinforced Polymer (FRP)
FRP material is only about ¼ of the weight of steel materials. It weighs approximately 120 pounds per cubic foot.
Timber
Timber is the lightest bridge material available. However, because it’s not as strong as other materials needed timber bridges require a larger volume of wood during construction. It’s important to note, timber is also far less durable than the other bridge materials.
Bridge Dimensions & Loading
The bridge materials along with the bridge’s dimensions – length and width – and how much loading it’s designed for will ultimately determine the final bridge weight.
To determine loading on the bridge, the type of use and environmental conditions will be considered. Type of loading could be for pedestrian traffic, equestrian use, and/or support of maintenance vehicles, snowmobiles, etc. Environmental conditions include wind and snow loading which will be determined by the location of the bridge.
FRP Bridge Weight Example
For example, if you have a 40 foot long and 5- foot wide FRP prefabricated pedestrian bridge, the bridge weight is approximately 4,300 pounds.
Bridge Installation
The pedestrian bridge’s final weight will significantly impact the overall cost of the bridge including materials cost, manufacturing cost, installation time and installation cost of your bridge.
Steel Bridge Example
A steel bridge might cost less for materials, but it will require heavy equipment to assemble and place the bridge.
FRP Bridge Example
The FRP can be broken down into lightweight parts. So, an FRP bridge can be light enough to be hand-carried into a worksite and easily assembled without heavy equipment. Additionally, FRP material can last 100+ years!
Why Does Pedestrian Bridge Weight Matter?
Understanding the importance of your pedestrian bridge’s weight will help you to make well-informed decisions throughout the design process. Suppose your bridge location is a remote, hard-to-access site. In that case, you will want to choose a material that transports and installs easily and will uphold for many years.
Take the Next Step with Areté Structures
Once you’re ready to move forward on your pedestrian bridge project, connect with the Areté team. We will work with you from the design process to delivery with an on-site, easy-to-follow set of assembly instructions.