Terminology

STRUCTURES: Engineering

Compression
Stress characterized by pressing together.

Dead load
The weight of the structure itself, independent of traffic or the environment, which must be supported by the structure. Compare to live load.

Deflection
The perpendicular distance a beam bends from straight, due to load and span.

Force
External influence on an object which tends to produce a change in its shape or causes movement.

Live load
The dynamic or moving weight, such as traffic, carried by a structure. Compare to dead load.

Moment
The tendency of a force to cause a rotating motion.

Parallel
Positioning of a member so that it is aligned with another in such a way that if extended the two members would not meet. Compare to perpendicular and transverse.

Perpendicular
Positioning of a member so that it projects out from or crosses another at a right angle. Compare to parallel and transverse.

Posttension
A type of Prestressing in which reinforcing tendons are fed through tubes which are covered by concrete poured into the form. Once the concrete cures and the forms are removed, the tendon is clamped on one end and jacked tighter on the other until the required tension is achieved. This produces a reinforced concrete beam with a postive camber which is able to withstand greater loads without deflection as compared to unreinforced beams of similar dimensions. Compare to pretension.

Prestressing
Methods of increasing the load bearing capacity of concrete by applying increased tension on steel tendons or bars inside a beam. Types of prestressing include posttension and pretension.

Pretension
A type of prestressing in which reinforcing tendons stretched to a desired tension and then covered by concrete poured into the form. Once the concrete cures and the forms are removed, the tension of tendon is transfered to the concrete increasing its compression and creating a positive camber. This produces a reinforced concrete beam which is able to withstand greater loads without deflection as compared to unreinforced beams of similar dimensions. Compare to posttension.

Also, cable hangers (or suspenders) used to support a bridge deck are commonly pretensioned before being attached to the deck.

Shear
Stress placed transversely on a member in opposite directions.

Strain
The deformation of an object caused by a force acting upon it. Compressive strain is the shortening of an object in compression. Tensile strain is the enlongation of an object in tension. Shearing strain is a lateral deformation caused by a force which tends to move part of an object more than another. Compare to stress.

Stress
The resistance of an object to external force. Compressive stress develops as an object in compression resists being shortened. Tensile stress develops as an object in tension resists being enlongated. Shearing stress develops as an object subject to shearing forces resists deformation. Compare to strain.

Structure
A stable assembly of components which carries a load while resisting various applied stresses, and transfers the load though its foundation to the ground.

Tension
Stress characterized by pulling apart.

Thrust
A force caused by one part of a structure pushing outward against another. The thrust at the abutments of segmental arch is also called drift.

Transverse
Positioning of a member so that it projects out from or crosses another, generally in a horizontal position. Compare to parallel and perpendicular. Also, describes a movement across the length of an object as opposed to along its length.




Submit info or inquiry - share some facts or ask a question.

Page created: 24-Feb-1999
Last modified: 24-Feb-1999

玩小处雏女免费观看_偷拍中国熟妇牲交_婷婷久久综合九色综合88