Arch bridges have curved arched shaped abutments at each end of the bridge formation. They are used to partially transfer the bridge’s weight. They will restrain the weight of the bridge, including the load it can carry, by throwing the weight in a horizontal direction. The next time you drive over a very long bridge take notice as to how many arches are included into the construction of that bridge. Long bridges are generally constructed by a series of arches.
Traditional arch bridges can be made from very simple materials which is an advantage for bridge contractors. Arch bridges must constantly be under compression and therfore masonry is a popular material used for the construction. Arch bridges constructed of masonry have a fill material placed above the arch because it can raise dead weight on the bridge. The masonry mix can also prevent extra tension to the arch ring as it faces heavier loads. Arch bridges include a system called centering which is the temporary use of false framing. Contractors realize that the bridges get stronger as the weight placed on it increases. Arch bridges can also be built out of nonreinforced concrete, brick, unprepared stone. These masonry built styles a re somewhat resistant to ground settlement and basically very durable but they require extra depths of of foundation because they are extremely heavy.
Modern arch bridges are constructed from reinforced concrete or steel and they the tension in their structure allows this style of bridge to carry a partial amount of load weight. This advantage eases the thrust against the abutments and makes them suitable for building on weaker ground support. But, modern arch bridges are not concidered to be “the real thing” because they are built from beams shaped like arches instead of the entire structure being a true arch.
There are three types of arch bridges that are used in the bridge construction industry today. Their differences may seem subtle but, depending on the use of the bridge, they make can make, or break, a quality arch bridge.
One type is the supported garden arch bridge which consists of an arch that supports the bridges deck by using a large number of vertical columns. Another type is the suspended deck arch bridge which consists of an arch that supports the bridges deck by using suspension tie bars or cables and sometimes utilizes truss type arches.
The last type id the tied arch bridge consists of a tie from one end of the arch to the other. This type of arch bridge is very strong and can withstand huge forces due to horizontal thrust.
There is also a modern evolutionary type of the arch bridge and is called the compression arch suspended-deck bridge. This bridge is constructed by light materials that are strong in tension. These materials include steel, reinforced concrete, and post-tensioned concrete.
So, in conclusion, when a bridge is planned for construction, the contractor has to research the area, the traffic, and the use of the bridge before decided on the necessary style. Arch bridges have to meet many specifications because they are carrying the lives of humanity.
Simon Douglass has been writing about cedar patio furniture for Adams All Natural Cedar for several years now. He has written descriptive articles for Adams featuring some of their products, like the garden bridge, for them to put on their website.