First developed for military use, temporary bridges are pre-engineered, modular structures that can be used to cross anything from drainage ditches, streams, and trenches to railway lines, or utility pipes that are buried close to the surface.
For the most part, temporary bridges are used to provide site access for construction vehicles and operatives, and are often seen bridging small culverts, rivers or sections of uneven terrain at the side of major motorways, or large building sites. They are generally between four and twelve meters long, and can be flat-packed for easy transportation and storage.
There are other types of temporary bridge though, as follows:
Temporary Pedestrian Bridges
Temporary Pedestrian Bridges are used to maintain access during construction projects, cross uneven or boggy ground, or ford obstacles so that pedestrians can go about their daily lives without too much disruption. Temporary pedestrian bridges are also used to ensure that foot traffic can reach inaccessible areas of a construction site.
Temporary Trench Crossings
Smaller than the average Temporary Bridge, a Temporary Trench Crossing (TCU) is a short, prefabricated unit that can be installed in under 15 minutes. They’re lightweight enough to be carried by a forklift, but are rated to carry heavy traffic, and can be installed side-by-side to create a wider crossing for cranes and large construction vehicles.
Large temporary bridge
Large Temporary Bridges are often used to cross rivers, railway lines or other impassable obstacles. They tend to have a stronger, more complex framework, and generally come packed as a set of pre-made sections that can be fixed together until the desired length is achieved.
Large Temporary Bridges can be used to reroute road traffic during construction projects, or allow heavy vehicles access to oil, mining or quarry sites located in rural areas. Some large temporary bridges are even used to cross major waterways, and are fully highway rated.
What are Temporary Bridges made of?
Technically speaking, temporary bridges can be constructed from anything that’s strong, flexible and durable enough to bear the weight its rated for. Historically, they’ve been built from crane mats, timber or scaffolding. Nowadays, most temporary bridges are made of galvanized or powder coated steel, prefabricated and then installed in a number of modular sections.
The floor panels are normally textured or coated to ensure that they are skid-resistant, and sturdy steel barriers are installed to guarantee that the bridge meets all necessary safety standards.
Thanks to their sturdy, steel frames, most temporary bridges are strong enough to be left in place permanently, but they can be rolled out in a few hours, and their flat-pack design means that there’s no need for heavy lifting equipment.
As mentioned above, the tensile strength of steel and the limitations of their modular construction does limit their length to approximately 12 meters in most cases, but they are a safe, reliable and dependable option for most modern applications.
Temporary bridges are also a very cost-effective solution to site access problems; in many cases, it’s very expensive to reroute, fill or pave over culverts, drainage trenches or streams, and a temporary bridge allows you bypass this work in favour of a relatively low-cost, hassle-free solution.