History of the Mississippi River Bridges
The Mississippi River is one of the most iconic rivers in the world, spanning 2,340 miles as it cuts through the State of Mississippi. It serves as a boundary between 11 different states, and it is a major shipping route for many goods and commodities. Over the centuries, countless bridges have been built over the Mississippi River, providing a safe and convenient way for people and vehicles to traverse the river.
Types of Mississippi River Bridges
The bridges built over the Mississippi River are generally categorized as either cantilever, arch, suspension, truss, and movable bridges, each with its own unique characteristics. Cantilever bridges, composed of two separate spans connected by a central support column, are one of the most iconic forms of bridges, due to the high level of stability they provide against wind and currents. Arch bridges, meanwhile, are defined by their use of curved stone or steel to support the weight of the bridge, while suspension bridges rely on suspenders to hang the deck across the span of the bridge. Truss bridges occupy a unique place, as they feature a series of triangular elements connected together to create a very rigid system, while movable bridges, such as drawbridges, are designed to allow ships and other boats to pass beneath them.
Notable Bridges of the Mississippi River
Along the Mississippi River, there are many noteworthy bridge designs. One of the most iconic bridges is the Wabasha Street Bridge, a two-lane cantilever bridge built in 1876. It is the oldest standing bridge on the Mississippi River, and is a popular tourist attraction. In addition, the Huey P. Long Bridge, built in 1933 is another impressive structure, built to span the river just outside of New Orleans. It is however overshadowed by the Huey P. Long Bridge Extension, built in 2011, which is the world’s longest and tallest railway bridge, spanning almost a mile across the river. Hundreds of thousands of vehicles cross the bridge each day, making it one of the most heavily trafficked bridges in the US.
How Many Bridges are Over the Mississippi River?
There are currently more than 200 bridges crossing over the Mississippi River, although exact numbers are difficult to find due to the sheer size of the river. Of these bridges, 91 are within the boundaries of the State of Mississippi, with the rest spread out among the other 10 states. It is notable that there are 2 bridge crossings between Arkansas and Tennessee, 8 between Illinois and Kentucky, and 11 between Minnesota and Wisconsin.
Costs and Benefits of Mississippi River Bridges
The construction and repair of Mississippi River bridge spans can be costly, with estimates on modern cantilever bridges alone ranging from $250 million to $400 million. Despite the potential for high costs, the benefits of having bridges across the Mississippi River far outweigh the costs. Bridges reduce the time it takes to travel via the river, while increasing safety, ease of transport, and allowing access to previously unreachable areas.
Challenges Facing Mississippi River Bridges
The Mississippi River is constantly changing and evolving, making the bridges built over it vulnerable to flooding and other natural disasters. As a result, bridges should be built with extra stability to ensure they can stand up to the conditions of the river. In addition, the age of some bridges poses another challenge, as many of the bridges crossing the Mississippi River are over 100 years old, with some even dating back to the 19th century. Maintenance and repairs on older bridges are necessary to ensure the long-term structural integrity.
Environmental Impact of Mississippi River Bridges
The presence of a bridge over a river can have both positive and negative impacts on the surrounding environment. On the positive side, bridges can reduce the level of disturbance created by boat traffic, providing stability for many fish, birds, and other forms of wildlife. On the negative side, bridges can disrupt natural flow patterns, causing sediment buildup or blockages. Bridges also produce physical impact, such as blocking the view of the river and creating noise pollution.
Impact of Mississippi River Bridges on Society
The presence of bridges crossing the Mississippi River have had a major impact on the region’s economy and transportation. By connecting the states together, bridges have drastically improved the ability of goods and services to be transported across the river. In addition, having physical access to previously inaccessible areas has allowed for the development of goods and services that would have been impossible without bridges. Most importantly, bridges crossing the Mississippi River have allowed for a much higher level of international commerce and communication, connecting states and countries together.
Technology Used in Mississippi River Bridges
Technology plays a major role in the construction, maintenance, and repair of bridges crossing the Mississippi River. Many modern bridges utilize GPS surveying to ensure proper placement and alignment of spans, while geotechnical analysis can help identify potential weak spots in the soil below the bridge. In addition, improved hydraulic hammer technologies have allowed for the efficient excavation of river bed sediment, allowing for more efficient construction.
Security of Mississippi River Bridges
The US government takes significant measures to ensure that bridges crossing the Mississippi River are secure from potential hazards such as terrorism, vandalism, or natural disasters. Many bridges, such as the Wabasha Bridge, are closely monitored by security cameras and surveillance teams, while many bridges are also equipped with innovative technologies such as fire suppression systems, radar systems, and electronic counters to detect potential threats.
Future of Mississippi River Bridges
The future of bridges crossing the Mississippi River looks bright, with many ambitious projects underway. One of the most impressive is the Hannibal Arch Bridge, a cantilever bridge, which is slated to open in the fall of 2021. The bridge will span the Mississippi River and connect two formerly unreachable areas of Missouri, providing an unprecedented level of economic and transportation freedom to the region.
