Pile–Pontoon Railroad Bridge

Old Pontoon Bridge North McGregor Iowa 1885

Pile–Pontoon Railroad Bridge is a type of bridge that combines the features of both pile bridges and pontoon bridges to support railroad transportation. This hybrid bridge design utilizes piles for permanent support structures and pontoons for additional support, especially in bodies of water where traditional bridging methods may be impractical or too expensive. The Pile–Pontoon Railroad Bridge is particularly useful in environments with variable water levels or where the bedrock is too deep for conventional piling.

Design and Construction

The design of a Pile–Pontoon Railroad Bridge involves the strategic placement of piles, which are long, slender columns driven deep into the ground or the bed of a body of water. These piles serve as the primary support. The pontoon elements of the bridge float on the water's surface, providing additional support and stability. These pontoons are anchored to the piles to prevent movement. The bridge deck is then constructed atop these supports, designed to carry railroad tracks and withstand the dynamic loads of passing trains.

Advantages

The main advantage of a Pile–Pontoon Railroad Bridge is its versatility and adaptability to various environmental conditions. This type of bridge can be constructed in areas with deep water or unstable bed conditions where traditional piling would be challenging or impossible. Additionally, the pontoon elements allow for a degree of flexibility in the face of changing water levels, making it suitable for locations prone to flooding or significant tidal changes.

Disadvantages

However, the Pile–Pontoon Railroad Bridge also has its disadvantages. The reliance on pontoons means that the bridge can be susceptible to damage from strong currents, ice flows, or debris. Moreover, the maintenance costs can be higher than for more traditional bridges due to the need to inspect and repair both the submerged and floating components of the structure.

Applications

Pile–Pontoon Railroad Bridges are relatively rare and are typically employed in specific circumstances where their unique advantages can be fully utilized. Examples include temporary bridges during the construction of more permanent structures or in remote locations where the transportation of heavy construction materials is logistically challenging.

See Also

• Bridge
• Pontoon bridge
• Pile bridge
• Railroad
• Civil engineering