RESEARCH
TRUSS BRIDGE:
A truss
bridge is a bridge composed of connected elements (typically straight)
which may be stressed from tension, compression, or sometimes both in response
to dynamic loads. Truss bridges are one of the oldest types of modern bridges.
The basic types of truss bridges shown in this article have simple designs
which could be easily analyzed by nineteenth and early twentieth century
engineers. A truss bridge is economical to construct owing to its efficient use
of materials.
ARCH BRIDGE
An arch
bridge is a bridge with abutment at each end shaped as a curved arch. Arch
bridges work by transferring the weight of the bridge and its loads partially
into a horizontal thrust restrained by the abutments at either side. A viaduct (a
long bridge) may be made from a series of arches, although other more
economical structures are typically used today.
CANTILEVER
A cantilever
bridge is a bridge built using cantilevers, structures that project
horizontally into space, supported on only one end. For small footbridges, the
cantilevers may be simple beams; however, large cantilever bridges designed to
handle road or rail traffic use trusses built from structural steel, or box
girders built from prestressed concretes. The steel truss cantilever bridge was
a major engineering breakthrough when first put into practice, as it can span
distances of over 1,500 feet (460 m), and can be more easily
constructed at difficult crossings by virtue of using little or no falsework.
DRAW BRIDGE
A drawbridge
is a bridge that can be raised to block passage or to allow boats or ships to
pass beneath it