anchorage—the end part of a suspension bridge into which the main support cables are attached
arch—a curved structure. Arches are designed to spread the load on top of them by transferring it to the sides and ground.
beam—a long, horizontal structural support piece held up by two posts or columns. Beams provide support for floors or roofs and can be made out of wood, metal, or stone.
bridge deck—the part of the bridge that spans the open space that people travel on
buttress—a structure that looks like half of an arch and is used to help support the roof of a dome. It is specifically designed to take a vertical load and spread it out in a horizontal direction.
cable—a support used primarily in bridge building that helps to hold the bridge deck up against the force of gravity. Similar to a rope, cables are usually made out of twisted steel wire.
cable-stayed bridge—a type of suspension bridge where the deck is supported by a series of diagonal cables strung from the towers to the deck. A cable-stayed bridge uses many separate support cables that are held up by the towers directly.
cantilever—a beam fixed at one end that can move freely on the other end. Cantilevers are used in bridges and other types of trusses. Cantilevers are used in bridges and other types of trusses where wind and varying load conditions make the forces on the structure constantly changing.
column—a vertical support structure similar to a post. Columns are used to support horizontal beams and buttresses.
compression—a force that squeezes objects together. It is the opposite of tension. When a building rests on columns or posts, the weight of the structure caused by gravity squeezes or compresses the columns on the two ends.
dead load—the non-varying load found to exist on different parts of a structure that is caused
primarily by the force of gravity pulling on the building materials.
dome —a round semi-circular structure used to cover a large open space in structures such as stadiums and cathedrals. Domes are a series of inter-connected arches that take the vertical compressional load in the center of the ceiling and push it out toward the sides.
force -- a push or a pull. Gravity, tension, and compression are forces that affect the design of a structure.
girder—a large beam
gravity—a force of attraction between two objects. Gravity is the force that pulls materials down toward the center of the earth. It is responsible for the weight of the object and the amount of dead load placed on a structure.
live load—the changing load placed on a structure by forces other than the weight of the structure itself. In the case of bridges, it could be due to vehicles crossing, wind, ice, or snow buildup.
mortar—a cement mixture used between stones and bricks to hold them in place
span—the part of a bridge located between vertical support elements
strain—the amount a material bends or stretches when a force is applied
stress—the amount of force put on an object
suspension bridge—a bridge held up by cables hanging from supports above the main bridge deck. Most suspension bridges have two main cables that are tied into heavy anchorage blocks at either end. The cables pass over towers and connect to the center of the bridge deck. Vertical support cables along the length of the main cable also connect to the bridge deck.
tension—a force that stretches or pulls things apart. The opposite of compression, it is found in the main cables of suspension bridges that are pulled tight along their length. In most structures, the forces of tension and compression must balance or the structure will fail.
truss—a frame made from beams that is designed to equalize the tension and compression in a structure. Triangular in shape, trusses take a vertical load and spread it out in a horizontal direction. Trusses can be seen in bridges where they stabilize the roadway.