Cost to Build a Bridge Over a Creek? The Breakdown

Bridges are an essential part of everyday life. They make it possible to cross water or ravines. But when they are not properly constructed, they can be dangerous for those who use them, especially if you want to build them on your property.

The California Department of Transportation has created a table to help you compare bridge costs to get you started. The table lists standard depth to span ratios, span ranges, and bridge cost per square foot of deck area. Read more if you want to know the details of the cost of building a bridge over a creek.

Cost Factors

The cost of a bridge can depend on several different factors. These include the trouble of terrain, the materials used, and the bridge’s purposes and longevity.

• Material and labor costs

You can use your workforce to save on labor costs or hire someone else. Are you using widely available materials (timber woods, planks) or industry-made? You may need to calculate also the hauling cost to bring in the materials.

• Surrounding environment

The distance from the top of the water to the soil. Add also the span of the creek, water discharge, and type of soil. Weather conditions in different seasons. Is it a flood during the rainy season that requires building a small dam? Will it block the downstream flow needed for irrigation?

A local civil engineer may be able to answer your question. They will be experienced & knowledgeable on the issue and can help you out legally regarding flood planes. You might also want to consult professional bridge builders or constructors for advice.

The location also plays a part. Depending on the type of terrain, a 1.5-mile stretch can cost less to maintain. Costs can vary significantly depending on the distance and project – the highest price is transportation (trucking material).

• Permission

Local permit, water rights, environmental studies, SEPA report (if you are in the United States). You need to consider these things even if you only need to build a local bridge in your property because of its overall effect.

It’s essential to check the regulations for your state and location before building a bridge, as smaller projects may fall under different jurisdictions. In some cases, meeting requirements can increase the cost of a simple task. Remember, the U.S. Army Corps of Engineers will be present as soon as a structure over water is mentioned.

• Bridge type and uses

Is it a foot bridge, ATV bridge, a car bridge, or a heavy truck bridge? You may need to put bridge design also into consideration. Is it a suspension bridge, truss bridge, or just a piling supported bridge? Will the bridge act as temporary, or do you want to make it last longer?

One possible enhancement that I haven’t seen done yet is making it more robust to handle larger vehicles. I’ve seen undersized culverts buried under driveways in some places, allowing the stream to pass under it. If it’s a broader stream, a few of them might be placed side by side with fill in between.

• Maintenance cost

Remember also, once you build your bridge, it’s your responsibility. You have to regularly maintain and inspect it to make sure that it stays safe and functional. The larger and more complex a bridge is, the more maintenance is required.

Bridges require constant upkeep to ensure they’re safe for people to walk across. One of the most important jobs of a bridge engineer is to inspect their structure as part of this maintenance process. They check out cracks in the concrete, wood deterioration, or steel cables that might need tightening up.

With this in mind, bridge building can cost you anywhere from zero to over one million dollars. Then how can you determine which bridge is suitable for your creek and condition?

Types of Bridges Over the Creek

From the simpler one with stone boulders to steel bridges and trusses, you have many choices at your disposal.

• Stone arch bridge

The Romans found that if they leaned stones against one another in the shape of an arch, they could span greater distances than using the stone as simple lintels or beams. This type of arch is more resistant to compression forces than any other configuration of stones. The angle will only be stable as long as the end supports act to restrain the curve.

For a point of reference, a 10-ton dump truck of stone is around $300 delivered. Stone prices can vary widely depending upon where you are located. For example, if you are 50 miles from the nearest quarry, that haul’s cost will be expensive all by itself.

You will need masonry chisels: 3″ wide, 1.5″ wide, 4) rotary drill with 9/16 bit, 7) plywood, /4s plywood for the base. For around $400-$800, you’ll be able to get all the materials you need for this project. If you already have some of the household tools, then it will be far cheaper!

Use any stone you happen to have on hand. Bought shot rock would be the largest size available and will need more time for cutting. If a person wants an excellent job done but still prefers DIY, one idea is to buy pre-cut landscaping stones for most of the job. It may be expensive, but it will save them both time and effort.

• Swinging bridge

A swinging bridge is also called a suspension bridge. The cost of building a homemade suspension bridge ranges from $1,000 to $3,000. They allow us to make the longest bridges possible. At first glance, they may seem similar to cable-stayed bridges, but some key differences make suspension bridges safer and more reliable in different situations.

• Used power or telephone poles

Recycled utility or telephone poles can be super cheap. You can get it as cheap as $1 per foot for them. Or, if you’re looking for a temporary bridge for 4wheelers, you could use a couple of cedar logs with 2 “x6” Pressure Treated boards. I built a couple like that as well. They’re to cross a gully/ditch.

If you need a good bridge for your four-wheeler, I recommend using pressure-treated timbers, three or four, to span your creek. You can get a 3-in x 4-in x 8-ft Pressure Treated Landscape Timber for about $4 to $7. Logs that are round (instead of flat) can provide you with a higher level of security and durability, which is why they’re the best log type.

• Cut down nearby trees.

If you have access to standing black locust trees, they will last two lifetimes for the beam. You can usually get shafts in 400mm thickness in 60m+ lengths, which is perfect for decking. Black locust boards will last 80-100 years.

If we’ve gone the DIY route, we can build a bridge by cutting two nearby trees down. That way, we only need to use pressure-treated 2×6 x 12′ boards, which we can cut in half for decking. Our bridge measures 6 feet wide, so it’s perfect for foot traffic or regular ATV traffic.

• Wooden Skid

Rather than purchase a landfill-bound item, consider making your own by getting used or new supply skids. Be wary of certain skids that are not made from the best lumber and may need to be reinforced with landscape timber. Look for American Society Quality (ASQ) stamped lumber for increased strength.

• Aluminum or steel bridge

These trail bridge kits are built to handle 1,500-9,000 pound vehicle loads & snow loads up to 90lbs/ sq ft. They are also ideal for ATV use. They’re comprised of a 6061 T6 Aluminium frame and anodized Aluminium fasteners – guaranteeing you’ll have a bridge for life.

Install this unit by using two socket wrenches, a cordless drill, and some essential tools (or none at all). Then, spend some time assembling the bridge in any configuration you need. Within hours, you can have your bridge ready. Their price range from $500 to $5000.

When you need to make a long-span beam, there are four main options: fiberglass, aluminum welded steel, or wood. You may be surprised to learn that in most cases, when you compare the cost and the payload of each, poles made from steel strips and recycled plastic end up costing less.

You can also have a bridge made out of I-beams and 2″ thick oak planks. This will be able to hold up anything that you cross it with.

• Box Culverts

You can use precast culverts to build a bridge over a creek quickly. One potential enhancement I haven’t seen yet is making it more robust to handle vehicles. I’ve seen undersized culverts buried under driveways, allowing the stream to pass under it. You might also take variety in size into account.

You’ll need to make sure the area is not wetlands & it’s worth checking if you want to build the culverts. If not, the hassle of trying to get approval most likely won’t be worth it. You can get culverts for $250 to $500 a ton, depend on the span and height.

If you’re going to build a sturdy and sustainable bridge, it’s the cheapest and most logical solution. However, there could be specs & minimum loads for bridges that vary by state or county. From my experience, it’s good to call up your local concrete provider and see what they can offer in terms of pricing and design before making any decisions.

• Prefab bridge and flat car bridge

Prefabricated means that the span supports are fabricated in a plant and delivered to the field ready to install. The best thing about modular bridges is that they can be fabricated as modules and then quickly installed. On the other hand, flat car bridges are essentially recycled rail cars.

I did some personal research on flat car bridges some time ago, and it seems like a great option. They are already engineered to handle heavy loads, and they’re easy to retrofit with railings, different wheel tracks, or decking. You can get ranges on average from $120 to $160/square foot. In contrast, a flat car can go up to $300 per square foot.

Conclusion

Different traffic loads will change the bridge’s cost and difficulty. They’ll also affect the type of bridge and its execution. And, of course, the prevailing construction trend often factors into your final cost estimate. As an engineer, I usually measure 20% lower than what we accepted as a bid.

Every bridge will have a unique cost estimate. It is not possible to provide an accurate estimate without knowing the specifics of the project at hand. The cost of a bridge project will depend on various factors such as the type, size, length, and location of the bridge; the availability of labor and materials; and contract terms with contractors.