Important vocabulary terms for this unit
TRUSS/ TRUSSES:
A truss is a support placed in a structure that creates triangles (notice how the pink line in diagram 1 creates 2 triangles in the face of the purple cube). Trusses are series of supportive triangular shapes that are used to strengthen a structure. Trusses are added to structures because the triangle is the simplest and strongest shape to hold weight. Trusses help strengthen structures such as bridges, roofs, and metal towers. The bridge on the left shows trusses in a simple truss bridge - notice how there are many different triangle shapes? This helps to distribute the compression and tension on a bridge so that all of the weight isn't concentrated in one place at once. |
COMPRESSION:
The inward pushing force that a structure feels when it is under pressure. Compression is felt when weight is applied to a structure, and continues downwards into the ground.
TENSION:
The outward pulling force that a structure feels when it is under pressure. Tension is the opposite of compression. Both kinds of pressure are present in structures, and engineers must build structures that can withhold both pressures. Structures are made to use both kinds of pressure against each other to make stronger structures.
BEAM:
The beam of a bridge is the roadway, path, or track that is travelled on. The beam of the bridge has to be very solid and is often made of reinforced internal structures such as steel trusses. The beam is meant to support a heavy load without bending. The red part of the structure on the left is the beam.
ABUTMENTS:
The structures at the end of the bridges (or the shore) that the rest of the bridge structure is build ON or INTO. The abutments hold the bridge's shape and raise the bridge up to the appropriate height. Abutments are very important in arch structures because the abutment keeps the arch in its shape, especially if the arch is in pieces and requires a keystone to be kept in place.
KEYSTONE:
The piece in the top center of a pieced archway. This piece is the final piece that is placed during the construction of an arch shape because it locks all the other pieces in place so that the arch can hold weight. The keystone works in unison with the abutments to keep the arch in its curved shape.
PIER:
A vertical (upright) structure that helps to bear the load of a horizontal (sideways) structure. Piers on bridges help support the weight of the beam by transferring the weight immediately to where it is anchored in the ground through compression.
A vertical (upright) structure that helps to bear the load of a horizontal (sideways) structure. Piers on bridges help support the weight of the beam by transferring the weight immediately to where it is anchored in the ground through compression.
Graphics Used and Edited on this page: (All Images were re-uploaded 30/10/2013)
Truss http://www.rlt.com/20111
Compression tension http://hendrix2.uoregon.edu/~imamura/102/section2/chapter12.html
Keystone (edited) http://www.ldsces.org/manuals/doctrine-and-covenants-and-church-history-seminary-teacher-resource-manual/dc-trm-2-1-40-dc2.asp
Piers (cropped and edited) http://www.masstec.org/teched/mcasquestions.html
Truss http://www.rlt.com/20111
Compression tension http://hendrix2.uoregon.edu/~imamura/102/section2/chapter12.html
Keystone (edited) http://www.ldsces.org/manuals/doctrine-and-covenants-and-church-history-seminary-teacher-resource-manual/dc-trm-2-1-40-dc2.asp
Piers (cropped and edited) http://www.masstec.org/teched/mcasquestions.html