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## PowerPoint Slideshow about ' Earthquake Engineering' - donagh

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“8.9 Quake Strikes Japan—Nation’s worst in 140 years”

Airport, Sendai, Japan

Fukushima-Daichi nuclear power plant

Earthquakes Past and Present years”

Sendai, Japan (8.9 magnitude)

historical Seismicity Map

http://earthquake.usgs.gov/eqcenter/recenteqsww/

http://earthquake.usgs.gov/earthquakes/world/seismicity_maps/world.pdf

A pan-global issue…. years”

http://www.mapsofworld.com/world-major-earthquake.htm

Some Major Earthquakes, Past and Present years”

Christchurch, NZ 2011

Talca, Chile 2010

Port-au-Prince, Haiti, 2010

Guandong, China, 2008

Fukuoka, Japan, 2005

Izmit, Turkey, 1999

Northridge, CA, 1994

Mexico City, 1985

Why bother? years”

Sendai Japan Earthquake 2011 years”

Amazing engineering: Buildings Sway Without Collapsing

Different Buildings years”

Different model parameters

The Fundamental Questions years”

- Can we predict how different buildings will respond to an earthquake?
- How can we use this information to engineer a safe structure

Tabas years”, Iran 1978 Earthquake

Acceleration record is messy. No way to integrate Duhamel’s integral. No worries, computers to the rescue!

Relative motion of building and ground

Impulse Response Function

Measured Acceleration/USGS data

Ground acceleration (units of g) years”

z = 0.05is assumed

Z(t) meters

marks |z|max

If we found |z|max for a continuous range of wo, we’d get the Spectral Displacement

(Displacement Spectrum)

Z(t) meters

Z(t) meters

Averaged Spectra years”

To Many (88) Earthquakes

Spectra For El Centro Ground Motion

Velocity

Acceleration

Displacement

Natural Period (sec)

Figure Credits: L A Chopra, Dynamics of Structures, Chap 6

Right: G. Housner “Strong Ground Motion” in Earthquake Engineering, R Wiegel, editor.

Tripartite Representation years”

SD = spectral displacement

SV = spectral velocity

SA = spectral acceleration

SA/wo = SV = woSD

Housner spectrum for years”z = 0.05

Seattle Monorail years”

- Seattle, WA is a beautiful city, but is prone to large earthquakes. The monorail on the bridge has previously been measured to have a natural period of 2 s. Damping is assumed to be 2%. During an earthquake, is the trolley likely to derail? Use the Housner spectrum to find out!

Picture from: http://bcostin.wordpress.com/2008/02/25/seattle-worlds-fair-1962-postcards/seattle-monorail/

Beach House years”

- You are hired as an architectural engineer to build a California dream house on a hillside. The structure can be idealized as shown (on chalkboard). The frame is built out of concrete (E = 30x109 Pa). The support columns have a cross section of 10 inches squared. Assume damping is 5%. Determine the base shear in each column, which is more likely to fail?

Base Isolation Configuration years”

Figure credit: Michael D. Symans, PhD Rensselaer Polytechnic Institute: http://www.nibs.org/client/assets/files/bssc/Topic15-7-SeismicIsolation.pdf

Reduced Shearing in Superstructure. years”

Conventional Building

Base-Isolated Building

Figure credit: Michael D. Symans, PhD Rensselaer Polytechnic Institute: http://www.nibs.org/client/assets/files/bssc/Topic15-7-SeismicIsolation.pdf

Lead-Rubber Bearing years”

Shear Modulus

E ~ 0.5 – 1.0 MPa

Figure credit:sMichael D. Symans, Rensselaer Polytechnic Institute: http://c.ymcdn.com/sites/www.nibs.org/resource/resmgr/BSSC/Topic15-7-SeismicIsolation.pdf

LRB decreases years”keff and wo

Reduces shearing in columns…………but increases displacement

LRB Isolation in Action years”

Rubber Base Isolators

How do we model what we just saw? years”

Displacement , u

Frictional Pendulum System years”

Image credit: http://www.asee.org/documents/sections/pacific-southwest/2008/Porbaha_Ali_et_al%20Base%20isolation.pdf

Concept of Frictional Pendulum years”

Image credits: http://www.asee.org/documents/sections/pacific-southwest/2008/Porbaha_Ali_et_al%20Base%20isolation.pdf

http://nees.buffalo.edu/docs/dec304/FP-DC%20Report-DEMO.pdf; laconservancy.org

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