4: Seismic Risk Mitigation Flashcards
Land use planning is based on ____ ____ maps
hazard micro-zonation
What are the four main factors that should be accounted for in land use planning?
(1) probability of EQ intensity (2) peak ground accelerations (3) areas prone to secondary EQ effects such as liquefaction, flooding (4) building vulnerability: fire potential, distance from communication lines
What is Eurocode 8, and when was it introduced?
A regulatory code for new infrastructure, 1998
What is the main problem with building codes worldwide?
Not always enforced
Anti-seismic design principles require understanding of ____ and _____
How the ground shakes during an earthquake, how built structures respond
Name the five main ways that damage to buildings during earthquakes can be reduced.
(1) Strengthening structures (2) Isolating bases of buildings from ground (3) Using dampers to reduce vibrations (4) Installing dynamic control systems (5) Securing building contents and services
If the ground shakes at the buildings ____, the building shakes more strongly, which is known as ____
Fundamental frequency, resonance
What is the general range of frequency that a ground shakes at during an EQ?
0.1 – 10 hz
Taller buildings tend to have ___ fundamental frequency due to increased ___ and reduced ___
lower, mass, stiffness
The general rule is that a buildings frequency is about ___ Hz divided by ___
10 hz, number of floors
____, ____ structures with a height : width of ____ tend to preform best in EQ’s
symmetrical, continuous, <4
When it comes to extending a building, avoiding ____ is useful for EQ mitigation. The building will stand to be more earthquake proof if all structural elements of the building are ____
differential materials, securely connected together
What three ways can we test structural integrity of a building to mitigate EQ hazard?
Shake tables, computational models, real EQ observations
Ideally building materials should be a combination of high ___, high ____ and low ____ for earthquake hazard mitigation
High strength, high ductility, low weight
What is the best material to use as a strengthening material for earthquake hazard mitigation?
Timber
What are the three possible disadvantages of using timber for earthquake hazard mitigation
Unavailable, vulnerable to fire, vulnerable to rotting
___ is the next best property to use after timber, due to its ___ and ___ properties.
Steel, strong, ductile
Reinforced concrete has a ____ strength to weight ratio compared to timber and steel.
Poor
The worst strengthening material used in buildings is ____, as it is ___ and ___.
Unreinforced concrete, brittle and heavy
____ a building is usually cheaper than ____ a building when it comes to seismic hazard mitigation, but it is still costly and requires ____
Strengthening, rebuilding, careful planning
In poor rural areas it is best to concentrate on what three ways of building improvements?
Removing defects, low-cost strengthening, education for builders
What are the three main high-tech earthquake-engineering approaches?
Base isolation, damping, dynamic control systems
Base isolation places ___ between the ___ and the ____, made from layers of ____ and ___. The design allows high ___ strength but low ___ strength, allowing for ___ motion during an earthquake
Bearings, foundation and ground floor, rubber and steel, vertical, horizontal, horizontal
What are the three types of earthquake damping systems?
Viscous damper, friction damper, yielding damper
What does a seismic damping system do?
Absorbs seismic energy
What would the three types of seismic damping systems look like when implemented into a building?
See Picture
Give an example of a dynamic control system as a type of earthquake hazard mitigation currently in place today
Taipei 101 building in Taiwan, a pendulum which moves against the mass movement of the building due to EQ or wind hazards.
What is a dynamic control system as a type of earthquake hazard mitigation?
An intelligent system which adjusts to correspond with shaking or movement of a building
Name a way that a household could monetarily cover themselves for earthquake damage
Earthquake Insurance
What technological characteristic makes EQ early warning systems possible?
EM waves travel faster than S waves
What is the single station approach in an earthquake early warning system?
Station detects P-wave and issues the alarm on site
What is the network approach for an earthquake early warning system?
Station detects P-wave, issues the alarm onsite and instantly passes on to neighboring stations, who issue their own alarm. Combines information from everywhere.
What is one advantage and one disadvantage for the single station approach for an earthquake early warning system?
Advantage: rapid, Disadvantage: significant uncertainty
What is one disadvantage and two advantages for the network approach for an earthquake early warning system?
Advantages: better warning at greater distances, more accurate. Disadvantage: slower for epicentral region
What is the main limitation for an earthquake early warning system?
Only gives seconds of warning – not enough time for evacuation
What is needed for an accurate and effective networked early warning system?
Density and scope of the systems across potential hazard region
What is the USGS’s automated earthquake response system?
PAGER
