Glossary
Abutment – The outermost end supports on a bridge, which carry the load from the deck
Anchorage – A secure fixing, usually made of reinforced concrete to which the cables are fastened
Beam – A rigid, usually horizontal, structural support element
Bedrock – The solid rock layer beneath sand or silt
Brace – A structural support; (v) to strengthen and stiffen a structure to resist loads
Cable – A structural element formed from steel wire bound in strands; the suspending element in a bridge
Caisson – A watertight, dry chamber in which people can work underwater
Cantilever – A projecting structure supported only at one end, like a shelf bracket or diving board
Catenary – The inverted arch shape that the main cables of a suspension bridge make by supporting the weight of the bridge’s deck
Cofferdam – A temporary dam built to divert a river around a construction site so the dam can be built on dry ground
Column – A vertical structural support element
Compression – A pressing force that squeezes a material together
Concrete – A mixture of water, sand, small stones and gray powder called cement
Deck – Supported roadway on a bridge
Deform – Change in shape
Force – Any action that tends to maintain or alter the position of a structure
Joint – A device connecting two or more adjacent parts of a structure; a roller joint allows adjacent parts to move controllably past one another; a rigid joint prevents adjacent parts from moving or rotating past one another
Load – Weight distribution throughout a structure; loads caused by wind, earthquakes and gravity affect how weight is distributed throughout a structure
Maximum Credible Earthquake – An earthquake of magnitude 8 on the Richter scale along the San Andreas Fault, or a magnitude 7.25 quake along the Hayward Fault
Pier – A vertical supporting structure, such as a pillar
Pile – A long, round pole of wood, concrete, or steel driven into the soil by pile drivers
Pile Driver – A noisy machine that repeatedly drops a heavy weight on top of a pile until the pile reaches solid soil or rock or cannot be pushed down any farther
Shear – A force that causes parts of a material to slide past one another in opposite directions
Span – The distance a bridge extends between two supports
Stable – Ability to resist collapse and deformation; stability characteristic of a structure that is able to carry a realistic load without collapsing or deforming significantly
Steel – An alloy of iron and carbon that is hard, strong, and malleable
Stiff – Ability to resist deformation
Strong – Ability to carry a realistic load; strength the measure of a structure’s ability to carry a realistic load
Suspension Bridge – A bridge in which the roadway deck is suspended from cables that pass over two towers; the cables are anchored at either end of the bridge
Tendon – A pre-stressed cable, strand or bar
Tension – A stretching force that pulls on material
Tower – The vertical structure in a suspension bridge or cable-stayed bridge from which cables are hung
Truss – A rigid frame composed of short, straight pieces joined to form a series of triangles or other stable shapes
Unstable – Characteristic of a structure that collapses or deforms under a realistic load
Superstructure – A section of a bridge that is supported from beneath