How to Buy a Timber Vehicular Bridge

The following outlines some of the specifics that you need to consider, research, or decide during the process of purchasing a bridge.    YBC Sales Representatives are available to guide you through each step of the process, and look forward to discussing your specific needs. 

1.  Consider your project and construction timeframes.  At what stage is your project - i.e., preliminary budgeting stage?  When will the project begin construction?  Do you need the bridges at the beginning of project to provide access for construction equipment?  Will the bridge portion of the project be contracted through the owner or a subcontractor? 

2.  Become familiar with bridge terminology.  This will a great advantage when speaking with permitting agencies and bridge construction companies.  YBC has compiled a glossary at our Commonly Used Terms page.

3.  Consider the usage of the bridges.  Who/what will be using the bridges?  What is the capacity requirement?  How long with they be?  Do you need to meet AASHTO highway requirements?  How many lanes of traffic will the bridge need to accommodate?  Will you need it to support utilities?

4.  Consider the site.  When you are determining the exact location and layout for a bridge, some of the specifics that you will need to take into account are:

• Terrain
• Environment
• Grading 
• Access to the site (to both sides if you are choosing a freespan structure)
• Is there a more desirable location (potentially a shorter distance, better ground conditions, etc)

5.  Consider potential permitting and environmental issues.  This is a very large consideration that can greatly impact the plan for your project.  Within this area you may need to research the following:

• Are there environmental restrictions? 
• Are there certain materials that will be prohibited in the crossing area?  
• How wide is the wetland area?  Is there a buffer zone extending past this?
• Are piling permitted throughout the length of the crossing?  If not, at what points are they prohibited?
• What types of builders can deal with environmental restrictions?
• Are there limitations on the construction methods?  Although YBC typically constructs from the deck of the bridge; knowing the flexibility or limitations of entering the area being crossed is imperative.

Contact your local permitting authority for assistance in answering these important questions. 

6.  Consider the terrain the bridge will be spanning.

• What will the bridge be crossing (water, wetlands, ravine, etc.)?
• Is there water present?
• How deep will the water be during construction?
• How deep can the water get (i.e. 100 year flood line)?
• What is the salinity of the water (salt, fresh, brackish)?  This can impact the treatment required on the piling and the hardware that will be used on your project.
• What is the flow of the water (fast, stagnant, slow)?
• Are soil reports available?  YBC recommends procuring soil reports for all bridge crossings prior to finalizing the design of your bridge.  Although this does not provide a guarantee of what will happen during pile driving; this will aid in determining the best span type.

7.  Determine the span type that you would prefer and that would be most suitable due to any potential restricted areas.

8.  Begin to picture the details of the bridge, measure the proposed crossing and ask for initial budgetary pricing. 

Use the guide below to help you measure accurately.  If the crossing is of a basic nature, the following measurements would be helpful in quoting the price. 

Height - You will need to know the distance from the deepest location of the pond, ravine, creek, etc. to the top of the deck of the bridge. You will determine the height by knowing:

•  The depth of the crossing in its deepest location. If the depth varies greatly from one side of the bridge to the other, a profile (side view) drawing will be helpful in accurately understanding your project.

•  Consider potential flood lines to determine the height of the deck from the top of the water.

•  When a Freespan Glulam Structure is built, consider the depth of the Glulam. This could be considerable depending on the total length of the bridge; contact your YBC representative for details.

Length - The drawing represents the fact that you will typically measure at least 5 feet, and perhaps 10 feet or more, past the top of the bank on each side of your crossing. Keep in mind when determining this figure any environmental constraints and set backs that may require more than 5 – 10 feet from the top of the bank.