Are you getting ready to install a bridge on your project site? Proper site preparation is the key to a safe and successful setup. Whether you are using temporary bridges for short-term access or setting up modular systems, here is everything you need to know before delivery day.

Regulatory and Ground Prep

  • Check local regulations: Be sure to check for any building permits or local municipal inspections that may be needed. Don’t rely on what you hear from your neighbor or even a local contractor. Call your building department directly.
  • Avoid soft terrain: No temporary bridges should ever be installed directly on soft, wet ground—such as wetlands, marshes, or visibly wet, soft soil. The structure will immediately sink when heavy loads are driven across.
  • Ensure solid ground clearance: Temporary bridges should be installed on at LEAST 5 feet of solid ground on either side of an open span—and 6 to 8 feet is even better.

Foundation and Leveling

  • Prepare the timber base: At either end of the bridge, you will need about 4–5 inches of gravel, and then a crosswise length of bolted timbers that are 8 inches thick, 48 inches wide, and 2 feet wider than the bridge. These timbers are what the actual portable bridges sit on.
  • Short-term adjustments: NOTE – If the bridge install is short-term and for lighter loads, the timber base can be eliminated. However, please be aware that temporary portable bridges can sink into the gravel base without that extra support.
  • Keep it level: Temporary portable bridges should be installed as close to level as possible. Being 12–18 inches out of level is not necessarily dangerous, but out-of-level bridges can tend to shift over time as heavy vehicles enter and leave the span.

Environmental Considerations

  • Watch the water levels: Portable bridges should be set well above the highest flood rating for any moving water. Moving water itself will not damage a bridge, but it can erode the banks beneath it. Moving water can also carry floating debris that quickly builds up behind a bridge, which can shift it off the foundation base of gravel and/or timber mats. You may need to raise the height of the bridge with an extra gravel base.
  • Protect local foliage: No bridge should be installed directly next to any tree that is to be protected. Due to the weight of the bridge and the heavy equipment used on the site, there can be soil compaction that can severely damage tree root structures.

The Spanweld Advantage

  • NOTE – Spanweld Bridges are engineered for temporary use with high-quality pre fab bridges designed for easy removal and portability to other sites. While they are perfect as pre fab bridges for quick relocation, they can also easily be permanently installed. Please note that permanent installation requires a site evaluation by a certified civil engineer, and additional welding & fasteners will be required.

KEEP AN EYE OUT FOR OUR NEXT POST ON ACTUAL BRIDGE INSTALLATION TIPS!