When you are ready to begin the design process, you will usually work with a bridge engineer to ensure all bridge requirements are met. You will provide basic pedestrian bridge design concepts, then the engineer will develop a safe and cost-effective bridge design.
Read this article if you’re looking for more information on calculating the cost of building a bridge.
Bridge Design Parameters
To design a bridge, you will need to identify five basic bridge parameters.
#1 Selection of Materials
A major decision for your bridge is which type of material to select. You will need to compare the cost and lifespan of the bridge while considering the long-term maintenance required. There are three primary bridge materials to consider during your selection process.
- Fiber-Reinforced Polymer (FRP) – FRP is corrosion-resistant and lightweight material with a lifespan of 100+ years. This material works exceptionally well for remote pedestrian crossings since it requires minimal maintenance. Learn more about FRP bridges.
- Steel – Steel provides a long lifespan and low maintenance, but bridge construction is challenging. Due to its heavy weight, it is difficult to transport and construct on remote trail systems.
- Wood – Wood bridge’s lifespan is about 30 years but will require frequent maintenance during that time.
#2 Aesthetic Requirements
Next, you will need to consider how you want your bridge to look. For instance, a simple stringer bridge might be the most cost-effective, but a truss bridge might be more attractive in the setting.
If you choose FRP as the material, you can select your preferred color. You can also choose decking material that appears more natural (i.e., wood) or choose a decking material that is more durable.
#3 Basic Dimensions of the Bridge
The length of the bridge is determined by the width of the obstacle to be spanned (creek, roadway, etc.). The bridge’s width is determined by the use of pedestrians, equestrians, light vehicles, etc.
#4 Decking and Hardware Types
You will need to determine the type of decking and hardware for your bridge. Keep in mind that you will choose the material based on durability, aesthetics, and cost.
#5 Rail Height and Type
The rail height may be incumbent in the design, but handrails can be added for aesthetics or to meet code.
Engineers Offer Cost-Effective and Optimized Bridge Designs
Working with professional engineers during the design process will help to guide you with your decisions regarding these design parameters. Engineers can use your design parameters to determine the configuration and materials needed for the bridge.
At Areté Structures, we contract Areté Engineers to assist with your project’s planning and design phase. Areté Engineers will use your basic design parameters along with standard parameters to recommend an optimized bridge design.
Standard bridge parameters Areté Engineers will consider are:
- Loading requirements based on the bridge use (pedestrian, equestrian, snowmobile, maintenance vehicles, etc.)
- Wind factors
- Snow loads
Additionally, Areté Engineers will use the Allowable Stress Design (ASD) Method with a safety factor of 3 built-in to ensure the bridge’s safety or AASHTO guidelines for FRP bridge designs.
3 Types of Bridge Designs
Based on your design parameters, Areté Engineers provides a design for one of three types of bridge designs.
1. Truss Design
This bridge design is an ideal and cost-effective choice for clearspans ranging from 25 to 80 feet long. This bridge design structure includes a railing as an inherent part of the design.
2. Stringer or Beam Design
If you’re looking for a boardwalk-style (a bridge without a handrail) or short-span bridge, this is a great option. The bridge span is typically between 10 to 24 feet long.
3. Underslung Truss Design
This bridge design is unique to Areté Structure and ranges from 40 to 65 feet long. This design includes all the structural members below the bridge decking. You can select decking and railing material for aesthetic or functional purposes.
Are You Ready to Take Action?
Now that you have more information on pedestrian bridge design concepts, the Areté Structures team can help you take the next steps. Throughout the design process, we work with you to build a bridge that will meet your needs and goals.
Contact the Areté Structures team to start your pedestrian bridge process.
