EARTHQUAKE HAZARDS Flashcards
The energy released by an earthquake sets many processes into action, and may have both short-term and long-term consequences. Some of the hazards take
effect immediately, and others may not
appear for days, weeks, or months after the
event
EARTHQUAKE HAZARDS
The amount of destruction associated with given amounts of ground motion depends largely on the design and construction of buildings and infrastructure according to specific codes.
Ground Motion
may have horizontal, vertical, or combined displacements across them and may cause considerable damage.
Ground breaks or ruptures
are also one of the causes of the rupture of pipelines, roads and communication cables during earthquakes.
Ground breaks
is the movement of material downhill. In most instances, it occurs by a slow gradual creeping of soils and rocks downhill, but during earthquakes large volumes of rock, soil, and all that is built on it may suddenly collapse in a landslide.
Mass Wasting
is a process where sudden shaking of certain types of water-saturated sands and muds turns these once solid sediments into a slurry, a substance with a liquid-like consistency
Liquefaction
also known as seismic sea waves, are usually generated from submarine landslides that displace a large volume of rock and sediment on the seafloor, which in turn displaces a large amount of water
Tsunamis
may be generated by the back-and-forth motion associated with earthquakes, causing a body of water (usually lakes or bays) to rock back and forth, gaining amplitude and splashing up to higher levels than normally associated with that body of water.
Seiche waves
great earthquake that can totally destroy communities near its epicenter
MAGNITUDE 8.0 AND GREATER (GREAT)
major earthquake causing serious damage
MAGNITUDE 7.0 TO 7.9 (MAJOR)
may cause major damage in populated areas
MAGNITUDE 6.1 TO 6.9 (STRONG)
slight damage to buildings
MAGNITUDE 5.5 TO 6.0 (MODERATE)
often felt, but only causes minor damage
MAGNITUDE 2.5 TO 5.4
usually not felt but can recorded by seismograph
MAGNITUDE 2.5 OR LESS
the inertia forces resulting from structural displacements are, in turn, influenced by the magnitude of the masses
LUMPED MASS APPROACH
-PERIODIC LOADING
-VARIESWITH TIME
DYNAMIC LOADING
SINGLE SOLUTION
STATIC LOADING
most effective for a system where the mass is quite uniformly distributed throughout. The deflected shape of the structure is assumed to be expressed as the sum of a series specified displacement patterns
GENERALIZED DISPLACEMENT PROCEDURE
most efficient for expressing the displacement of arbitrary structural configuration
FINITE ELEMENT PROCEDURE
the concept that a mass develops an inertia force proportional to its acceleration and opposing it.
DIRECT EQUILIBRIUM USING D’ALEMBERT
PRINCIPLE
if a system which is in equilibrium under the action of a set of forces is subjected to virtual displacement, then the total work done by the forces will be zero
PRINCIPLE OF VIRTUAL DISPLACEMENT
the variation of the kinetic and potential energies plus the variation of work done by the non-conservative forces considered during any time interval t1to t2 must be equal to zero
HAMILTON’S PRINCPLE
the response of a structure to a given dynamic excitation depends on the nature of the excitation and the dynamic characteristics of the structure, i.e., on the manner it stores and dissipates vibrational energy. When seismic excitation is applied to the base of a structure, it produces a time-dependent response in each element.
ELASTIC SEISMIC RESPONSE
While structures can be designed to resist severe earthquakes, it is not economically feasible to design buildings to elastically withstand earthquakes of the foreseeable magnitude.
INELASTIC SEISMIC RESPONSE
The energy produced in the structure by ground motion is basically dissipated through internal friction within the structural and nonstructural members.
DAMPING
Displacement of foundations
-Vertical displacement
-Rocking displacement
-Swaying displacement
Failure modes of shallow foundations
-Sliding
-Overturning
-Shear failure
is the result of rotation of an eccentric or a less rigid mass about the basic or the more rigid mass of the building.
TORSION
tend to exaggerate the joint rotation of the structural frame
CANTILEVERS
when some areas were uplifted by many tens of feet, the water table recovered to a lower level relative to the land’s surface, and soon became out of reach of many water wells that had to be redrilled.
Changes in Ground Level
Deformation on the ground that marks, the intersection of the fault with the earth’s surface.
GROUND RUPTURE
Disruptive, up, down and sideways vibration of the ground during an earthquake.
GROUND SHAKING
Phenomenon where in sediments especially near bodies of water, behave like liquid similar to quicksand.
LIQUEFACTION
Down slope movement of rocks, solid and other debris commonly triggered by strong shaking.
EARTHQUAKE-INDUCED LANDSLIDE
Series of waves caused commonly by an earthquake under the sea.
TSUNAMI
VULNERABIILITY OF A BOX ELEVATION
1-2
VULNERABIILITY OF AN INVERTED PYRAMID ELEVATION
4-6
VULNERABIILITY OF A L-SHAPED BUILDING
5-6
VULNERABIILITY OF AN INVERTED T ELEVATION
3-5
VULNERABIILITY OF A MULTIPLE SETBACKS ELEVATION
2-3
VULNERABIILITY OF AN OVERHANG
4-5
VULNERABIILITY OF A PARTIAL SOFT STORY
6-7
VULNERABIILITY OF A SOFT FIRST FLOOR
8-10
VULNERABIILITY OF A COMBINATION OF SOFT STORY AND OVERHANG
9-10
VULNERABIILITY OF A BUILDING ON SLOPING GROUND
10
VULNERABIILITY OF A THEATERS AND ASSEMBLY HALLS
8-9
VULNERABIILITY OF A SPORTS STADIUM
9-10
VULNERABIILITY OF A BOX FLOOR PLAN
1
VULNERABIILITY OF A RECTANGLE FLOOR PLAN
2-4
VULNERABIILITY OF A STREET CORNER FLOOR PLAN
2-4
VULNERABIILITY OF AN U-SHAPED FLOOR PLAN
5-10
VULNERABIILITY OF A COURTYARD IN CORNER FLOOR PLAN
4
VULNERABIILITY OF A L-SHAPED FLOOR PLAN
8
VULNERABIILITY OF A H-SHAPED FLOOR PLAN
5-7
VULNERABIILITY OF A COMPLEXED FLOOR PLAN
8-10
VULNERABIILITY OF A CURVED FLOOR PLAN
5-9
