Characteristics of the bridge beam
A beam bridge is the simplest type of bridge construction. It consists of a solid structural beam used to span a gap or crack. The beam is supported by springs on either side of the opening, or can even rest directly on the floor. Beam bridges typically span distances of less than 250 feet, making them a popular choice for viaducts and footbridges.
Excavation and supports
The construction of a beam bridge begins with the installation of supports on both sides to support the weight of the bridge. Simple bridges are fixed to the ground without the use of supports, but this still requires preparation of the ground. The edges of the opening are tested to ensure they are stable. To increase stability, shoring or what techniques can be applied. It may also be necessary to fill or excavate the ground to fix the bridge to the desired height.
Usually, vertical springs are placed on any edge of the bridge to ensure proper support. These springs are made of masonry, concrete or steel and are often fitted into concrete to maintain a stable foundation.
Construction of the bridge
The span of the bridge itself is built in a different place then transported to the workplace. Beam bridges are made of two steel or concrete beams connected by some type of decking material. The beams can be formed by solid beams or constructed of webbed trusses to add strength. Once the bridge was lifted to the supports using a crane, then welded to ensure a firm connection.
Concrete beam is often made of prestressed concrete. This allows them to withstand the forces acting upon them. The upper part of the bridge is subject to compressive strength while the lower part is stretched due to the tensile strength. Of course, these forces are not visible on a beam bridge that is supported correctly.