How Much Does It Cost to Build a Bridge?

One of the most important parts of the modern evolution of infrastructure is bridges that enable people to travel over considerable areas that were previously unpassable. From very small wooden bridges that went over small rivers to those massive suspension bridges that you can see in movies over entire bays, the shape and size of a bridge can differ to quite a large extent.

Bridges are also a great place to begin for people who are thinking of doing an engineering project.

How Much Does it Cost to Build a Bridge Over a Creek?

The cost to build a bridge is anywhere between just $1,000 and over $10,000,000 or more, depending on the type and size of the bridge you’re planning to build, as well as other important factors.

The absolute minimum you should expect to pay for the simplest of all bridges is around $1,000 when building a wooden creek bridge for personal use only, using a prefabricated kit.

Building a bridge meant for public pedestrians will set you back about $250,000 or more, while larger bridges meant for both pedestrians and road traffic can easily cost more than $10 million, depending on its size and the materials it is made of.

As there are several important factors to consider when figuring out the cost of building a bridge, we will go over different types of bridges and factors that influence their price.

So what are the different types of bridges you can build?

Personal Bridge

Expect to pay at least $3,000 to have a professional install a permanent bridge for personal use over a creek or some ravine.

A swinging suspension bridge is probably the simplest type of bridge you will be able to build. It will consist of a series of planks hung between four posts.

There are also prefabricated swinging bridge kits you can buy. These will usually cost between $1,000 and $3,000. The more expensive end of this price range will usually include other materials and landscaping.

If you already have the needed tools and you know what materials you need, you can probably build a simple plank bridge for even cheaper, as low as $500. Keep in mind that these types of bridges won’t be very strong or stable. For example, there are some people who choose to build simple bridges using planks and rods.

Recycled telephone poles shouldn’t cost more than $1 to $3 per foot and two of them should be enough to place down as the main support. On top of this, you will also need pressure-treated boards that would usually cost around $5 per square foot of plank.

Automobile Bridge

The most expensive type you can build is the Automobile bridge. Any bridge meant for both automobiles and pedestrians will have to be made of very durable materials like concrete and steel. It will usually span over hundreds of feet.

Although most of them will easily cost $10 million or more, a standard auto bridge will cost at least $5 million. It isn’t unusual for a double lane car bridge to cost $50 million or more to have built.

An easier way of calculating the cost of a highway bridge is per linear foot, which costs around $4,500. So you should expect a 4,000-foot bridge to cost around $16 million. The largest bridges ever built around the world cost billions of dollars and span over several thousand feet.

One example is the Oakland Bay Bridge, built in Oakland, CA, which is known to have cost around $6.4 billion. On an international level, The Macau/Hong Kong Bridge cost over $20 billion to build.

Pedestrian Bridge

Pedestrian bridges are between the other two categories in terms of price to build and are usually meant for foot traffic. Pedestrian bridges range from smaller walkable bridges that are built in parks to massive boardwalks meant to support several hundreds of people and sometimes, even buildings. Due to the high range of variables in the building of pedestrian bridges when it pertains to their size, shape, or design, the costs will differ significantly.

Expect to spend at least $250,000 to build a pedestrian bridge where 10 to 20 people can comfortably walk at the same time. That cost is split between materials, landscaping costs, labor costs, and permit fees.

You might also like our articles on the cost of building a factory, a castle, or a hotel.

It will be easier to estimate the cost of a pedestrian bridge if you set a price of around $2,500 to $3,000 per linear foot. This means that a 150-foot pedestrian bridge will likely cost you between $300,000 and $450,000 to build. The kinds of materials you choose will influence this price quite significantly.

Factors that Affect the Cost of Building a Bridge

Intended Use

The overall size as well as the type of materials you will have to work with will be influenced by the intended use of your bridge. Things like the presence of guardrails or handrails will be influenced by whether the bridge is meant to carry automobile traffic or foot traffic, while its length will be determined by what the bridge has to traverse. (Is it going over a lake? river? creek?)

You should know that bridge configurations are built following National AASHTO Standards. This is to ensure engineering integrity and safety. Most engineers will have to make some trade-offs in design to ensure that the bridge they build follows the agreed-upon standards.

Materials

The overall strength and configuration of a bridge, as well as its final price, will be significantly affected by the materials used to build it. There are three main materials that are usually used to build bridges. These are metal, wood, and synthetic polymers.

• Wood is mostly used for pedestrian bridges or those meant for small and sporadic cars and is one of the classic bridge materials. When compared to other types of materials, although cheaper, wood won’t be as long-lasting or as durable. Assuming it only faces normal weather conditions, you shouldn’t expect a well-built wooden bridge to last more than 25-35 years without periodic maintenance.
• Steel is susceptible to corrosion and rust over time but over than that, it is also very strong. Steel is a very heavy material. This means that depending on how much you need and the size of the bridge, you might have to get heavy machinery to move it in place and assemble it.
• Steel and concrete are a combination of two of the most common materials to be used for modern bridge construction. When building a large bridge that is meant for multiple car lanes, engineers use a steel frame in combination with concrete foundation blocks.
• Concrete is another one of the common materials that are used for building bridges meant for automobile traffic. Concrete is considered a great choice due to its properties that make it resistant to cracking due to contraction and expansion caused by heat, while also being easy to form. Concrete also comes with downsides, like the fact that it requires a lot of equipment to set up, as it is pretty heavy, which ultimately makes using it in construction rather expensive.
•  Fiber-reinforced polymers (FRP) or other synthetic materials can also be used when building a bridge. FRPs are the choice for people who need a material with increased durability and low weight. They have excellent resistance to corrosion and water. If you want to create a stronger structure, you can always combine FRP with metal or concrete. You can expect materials that incorporate FRP to last 50 years or more.

Construction Site

Before you can begin putting together the bridge construction, you will usually have to do some work on the construction site, regardless of the type of bridge you want to build. The development costs will be influenced by several factors, including the water level beneath it, the type of soil it is built on, the span of the bridge, and the distance between the top of the bridge and the soil.

Another important thing to consider is local weather during and after the construction. For example, to maintain soil integrity, bridges built in places that receive a lot of rain might need extra maintenance work. The kind of soil also plays an important role. You might have to do some heavy digging to install support beams in a location with tough bedrock.

Associated Construction Costs

There are several miscellaneous costs you will have to consider when building a bridge. As the size of the bridge increases, these cost ranges increase as well. For example, a small bridge built on private property and designed for personal foot traffic might not need extra work.

Bigger bridges on the other hand, designed for public transport, will likely need environmental safety tests before they are approved by local governments. They will likely require permits if they will be used for public foot traffic.

For larger projects, you will also have to consider the average costs of the added labor and equipment rentals.

Conclusion of bridge construction

Bridges are one of the most useful engineering inventions of the modern world. They have helped people move over big areas that were unpassable. If you want to build a small bridge intended for personal use, then you can expect to spend around $1,000. For big bridge projects that have multiple car lanes, the price will go into the millions or even billions of dollars.

Frequently Asked Questions

Can anyone build a bridge?

This depends on the type of bridge you want to build. Small bridges built on private property for personal use can be built by anyone and come with little to no restrictions.

If, on the other hand, you want to build a public bridge, you will probably have to go through official ways, work with certified professionals, and have the bridge design inspected and tested.

What is the average width of the bridge?

Most single-lane bridges meant for automobile traffic are around 14 feet wide. There are small bridges made for pedestrians that can measure 5 feet in width.

When it comes to large bridges that have multiple lanes for both walking and auto traffic, these can easily span over 100 feet in width.