A force acting along the long axis of a member or vertically in a wall.
A means of limiting the seismic forces on a building by supporting it on devices that allow relative movement to occur between the building and its foundation.
The horizontal force at the base of a structure due to inertial forces acting during earthquake ground movement.
Occurs in a structural element (such as a beam) when forces are applied at right angles to the element so that it bends. Bending moments produce tension on one side of the element and compression on the other side.
Canterbury Earthquake Recovery Authority.
Measures the properties of soil beneath the surface in a particular location.
Used to make reinforced concrete beams and columns stronger and more ductile so they can perform better in an earthquake.
Cone penetrometer test.
A flat (usually horizontal) structural element or system that transmits horizontal forces (typically from wind or earthquakes) to and from shear walls or frames.
A precast/prestressed concrete unit commonly used in floors or roofs.
A pile made of timber, steel or precast concrete that is typically hammered into the ground to form foundations.
A measure of how easily a solid material (such as a metal) deforms under stress without breaking.
eccentric braced frames
Frames with diagonal bracing that is not concentric.
An investigation by a specialist engineer or geologist into the physical properties of the rocks and soils at a particular location.
Techniques to improve the strength and stability of soil so it better supports a building.
Precast, prestressed concrete slabs that have tubular voids running through the full length, making them much lighter than solid slabs of equal thickness.
A damper that absorbs energy by allowing the metal to yield, either by bending or in tension and compression, depending on the design of the damper.
Initial evaluation process, usually carried out by a local building control authority to determine whether a building is likely to be earthquake prone or an earthquake risk.
Forces that act in the same plane as the face of the wall.
A pile that goes into the ground on an angle rather than vertically so as to better resist horizontal forces.
A measure of the effects of an earthquake on people and buildings at a particular location. The intensity at a particular site depends on the strength (magnitude) of a quake, how far the site is from the epicentre of the earthquake and the geology under the site. Intensity is measured with the 12-point Modified Mercalli Intensity (MMI) scale.
The difference in sideways movement between two adjacent storeys.
Horizontal or sideways loads on the building.
Earthquake forces cause the sand and silt particles to rearrange themselves into a more compact volume, and the water is squeezed out of the reduced space between the particles. The loose granular soil starts to lose strength and behave like a dense fluid – hence the term ‘liquefaction’.
A force applied to a structure.
Design that means that, after a building displaces sideways in an earthquake, it will return to its original position.
A measure of the strength of an earthquake (the amount of energy it releases) at the point where it occurs.
maximum considered earthquake
An earthquake that has a 2% probability in 50 years or a 2,500 year return period.
A structural frame typically consisting of reinforced concrete or steel beams and columns that are rigidly connected at their joints. Resistance against sideways forces of wind or earthquakes is by bending of the frame members.
normal force/normal load
A force acting at 90° to an object.
Forces that act at right angles to the face of the wall.
plastic hinge/potential plastic hinge
The zone in a concrete beam or column or shear wall where reinforcement yields or stretches under earthquake loading.
PREcast Sesimic Structural System
A technique where unbonded, tensioned cables or bars are threaded through precast concrete walls, beams and columns, with jointed ductile connections. The cables and ductile joints let the building spring back to its original position after a large earthquake.
PREcast Seismic Structural System.
The average number of years between earthquakes of a certain magnitude on a particular fault or at a particular location.
serviceability limit state
Buildings that can still be used for their intended purpose after an earthquake of the magnitude that can be expected once or twice during the life of the building.
Forces acting in a direction parallel to the face of the material or to a planar cross-section of a body.
A structural wall, commonly of reinforced concrete or timber, that often starts at the base of a building and runs for its full height.
standard penetration test
A test to provide an indication of the density of the soil.
Structural Timber Innovation Company – a company set up to develop the use of post-tensioned LVL (laminated veneer lumber) structures.
ultimate limit state
This is concerned with the safety of people in buildings. To stay within its ultimate limit state, a building must still be standing after being subjected to its peak design load.
Concrete, stone or brick masonry that has no reinforcing steel.