Characteristics of Beam Bridges - Types of Beam Bridges
Beam bridges basically consist of beam that is laid across the piers or supports. The beam should possess the strength to bear the loads that are expected to be placed on it. These loads are borne by the bridge piers. The loads cause the beam top edge to be compressed, while the lower edge is being stretched and is under tension.
Existing beam bridges are formed by girders, normally box girders, trusses or I-beams, that are supported on strong piers.
Box girders are stretched, box shaped elements that are more suitable to bear the twisting loads.
Trusses consist of one or more triangular units connected at joints or nodes.
I-beams are economical and simple to fabricate. They are simply beams with an I-shaped or H-shaped cross-section. The horizontal elements of the "I" design are flanges and the vertical is the web of the construction.
Other beam bridges may be fabricated from concrete beams that are pre-stressed. These materials possess the steel characteristics to endure loads in tension, and concrete strength to bear the compressive loads.
The beam bridge's strength is largely influenced by the distance between the piers. Therefore, the beam bridges are normally not suitable for longer length, unless several such bridges are connected with each other.
The beam bridge's span is dependent upon the beam weight and the materials strength. As the bridge material thickens, its capacity to hold the loads increases. Therefore, the span could also be increased. However, a sturdy beam may become too heavy, and sag. The beam bridges can be supported by the utilization of trusses.