Download Earthquakes and Architecture

Earthquakes
and
Architecture
What is an
earthquake?
An earthquake is a sudden
release of energy due to shifts
in the earth’s plates that has
been stored in the rocks
beneath the earth’s surface
which causes a trembling or
shaking of the ground. The
energy that is released from the
ruptured rock travels in waves
which are known as seismic
waves.
There are two types of seismic
waves; body waves which
travel through the interior of
Earth and surface waves which
travel on Earth's surface. The
two body waves are primary
waves (p-waves) and
secondary waves (s-waves).
http://www.vibrationdata.com/earthquakes/kobe.htm
Kobe Earthquake Japan 1995 Structures in Kobe built since 1981 had
been designed to strict seismic codes. Most of these buildings withstood the
earthquake. In particular, newly built ductile-frame high rise buildings were
generally undamaged.
The compressional (push-pull)
wave will vibrate parallel to the
direction that the wave is
traveling up to speeds of 4 to 8
km per second (2.49 to 4.35
miles per second). The S-wave
vibrates perpendicular to the
direction of travel and can travel
up to speeds of 2 to 5 km per
second ( 1.24 to 3.11 miles per
second).
Love waves and Raleigh
waves are known as Surface
waves. Surface waves are the
slowest of the seismic waves,
but because they travel near the
surface of Earth and contain a
range of oscillating frequencies
they often cause the most
damage
http://www.berkeley.edu/news/berkeleyan/2006/01/18_resumption.shtml
Northridge Earthquake Southern California 1994
•www.forceborne.com/FBW/Tech/fault_line_chart.htm
World Earthquake Fault Lines
Plate Tectonics
A spreading boundary is where the tectonic plates are separating. These
are places where volcanic activity is at a premium because the crust is
being torn open (as in splitting and cracking, like an egg breaking open).
New crust is forming when molten lava from deep down oozes out of the
cracks where the plates are coming apart .
A converging boundary is when one plate (usually the lighter
continental crust) rides up over the top of the other it's called a
subduction zone - because one plate margin is being subducted under
the other.
What is liquefaction?
www.scieds.com
This residential and commerial building sank more than
three feet into the partially liquefied soil.
Photo credit: Reinsurance Company, Munich Germany
www.scieds.com
Liquefaction is a type of ground failure in which water saturated sediment
turns from a solid to a liquid as a result of shaking, often caused by an
earthquake or even a volcanic eruption. In order for the liquefaction to
occur the sand grains must be fine grain sand that are not closely packed
together nor must it be held but some sort of cohesion. The intense
shaking causes the strength of the soil to become weak and the sand and
water begin to flow.
www.scieds.com
Adapazari, Turkey, 1999 Kocaeli earthquake
A major cause of damage
was liquefaction of the
recent alluvial deposits that
underlaid large portions of
the city. The result was
excessive settlements and
bearing capacity failures
for countless buildings,
most of which were
supported on shallow
foundations. This new
building was not yet
occupied at the time of the
earthquake. Again, the
bearing failure of its mat
foundation was related to
its relatively large heightto-width ratio.
www.scieds.com
What
do
Architects
do?
Architects design buildings and structures. They advise individuals, property
owners and developers, community groups, local authorities and commercial
organizations on the design and construction of new buildings, the reuse of
existing buildings and the spaces which surround them.
Architects work closely with other members of the construction industry
including engineers, builders, surveyors, local authority planners and building
control officers. Much of their time is spent visiting sites assessing the
feasibility of a project, inspecting
building work or managing the
construction process. They will
also spend time researching old
records and drawings, and
testing new ideas and construction
techniques. Society looks to
architects to define new and better
ways of living and working, to
develop innovative ways of using
existing buildings and creating new
ones. Architects can be extremely
influential as well as admired for their
www.cnn.com
imagination and creative skills.
www.architecture.com
What do Structural Engineers do?
Structural engineering's combine their knowledge
of science and design making as they construct
better framework for buildings and other structures
to safely resist natural and
made-made forces.
They are involved in physical
testing, mathematical modeling,
computer simulation all of
which support decisions that
Aid in the creation and maintenance
of safe and economical structures.
http://www.seaint.org /
http://cee-ux49.cee.uiuc.edu/strweb/home.html
www.earthscience.org/.../geopro/seismic/seismic.html
What is Earthquake Engineering?
Earthquake engineers are
concerned with creating
earthquakes resistant designs and
construction techniques to build of
all kinds
of bridges, roads and buildings.
Earthquake engineers are faced with
many uncertainties and must be
smart in their decisions in
developing safe solutions to
challenging problems. They rely
on state-of-the-art technology,
materials science, laboratory
testing and field monitoring.
www.sciencedaily.com
Earthquake-Resistant Structure
Building designed to prevent total collapse, preserve life, and minimize damage
http://nisee.berkeley.edu/elibrary/getpkg?id=GoddenD50-69
http://www.infinityfoundation.com/mandala/t_es/t_es_agraw_quake.htm
World’s Tallest Bridge Millau, France 2004
www.transport.polymtl.ca
San Francisco-Oakland Bay Bridge reconstruction, USA begun 2002
www.transportation1.org
High-Speed Magnetic Levitation Rail Line Shanghai, China 2004
Engineers chose a hybrid girder design that combined the rigidity, noise
absorption, and low cost of concrete with the precision manufacturing offered
by steel. The system’s reinforced-concrete support piers are designed to
withstand the seismic forces of earthquakes measuring up to 7.5 on the
Richter scale.
www.pubs.asce.org
Nepal Develops Earthquake Resistant Architecture
A plan for safer houses in rural areas
Nepal has a history of being devastated by major
earthquakes every 75 to 100 years, with the first
recorded as early as 1255 AD. In 1934 Nepal
experienced a deadly earthquake that resulted in the
death of 8,500 people and destruction of 20 percent
of valley structures, at a time when the population
was far less than at present. Seismologists are
predicting the occurrence of a large earthquake of
this kind in the near future, which is likely to be most
intense in the urban core.
http://www.archidev.org/rubrique.php3?id_rubrique=273
Ninety percent of Nepalese houses are made of stone and
unfired bricks. The Structural Engineers in Nepal are
retrofitting current structures for about $25/home. By
creating a one-meter square grid of punched holes in the
stone wall covered with a 10
cm mesh of bamboo on the inside
and outside the homes become
earthquake resistant. This net is
Secured to the wall by means of
12-gauge Gabion wire, (a form of
riprap contained in a wire cage that
is very useful in erosion control.),
which is inserted through the
holes and fastened strongly. It is covered with a stucco
of mud, which is used in rural areas in order to ensure
longer life for the bamboo mesh.
The Lefkas (Greece) earthquake resistant
technique Two-story houses are built with a ground
floor of rough boulder masonry and three lines of wooden
posts (one along each long wall, and one in the middle of
the room) support the first floor. This one is erected in
wood-frame construction (Dajji).
Foundations are laid on a three-layer round-poles mat,
which could behave as a spring if a gap was left around.
The main benefit is outspread of the foundation surface.
"Dajji" is traditional in Cashmere (India). It is
very efficient and affordable. A wooden frame is
built without bracing. The empty rectangular or
square "panels" are filled with a mesh of wood and
stone cemented with mud. These panels work as
bracing, but allow slight movement, and give
elasticity to the whole structure. Thus, the house is
able to move and to absorb the earthquake’s
movement.
Another advantage of this technique is to be
(comparatively) lightweight, and thus being less
stressed by earthquakes.
http://www.archidev.org/article.php3?id_article=1027
Kobe Earthquake
Japan 1995
6.9 Magnitude
Homes and building construction was older built with heavy tile roofs
that collapsed
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html
Another anomaly was the large number of about 20-year-old high rise buildings
that collapsed at the fifth floor. The older version of the code they were built
under allowed a weaker superstructure beginning at the fifth floor.
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html
Behind this completely collapsed wood-frame house is a house of reinforced concrete
that suffered no structural damage. The number of wood versus masonry buildings that
collapsed in Kobe astonished most observers, as wood-frame structures are usually
thought to be much better at resisting shear forces. Possibly the concrete house was
better-designed and stronger even for its greater weight. The proportionally heavier tile
roofs on wooden houses also might have been a factor.
http://www.niksula.hut.fi/~haa/kobe.html
http://www.niksula.hut.fi/~haa/kobe.html
http://www.city.kobe.jp/cityoffice/15/020/quake/disaster/d-index_e.html
Mexico City Earthquake, 1985
8.1 Magnitude
Poorly constructed buildings caused thousands of deaths
http://www.johnmartin.com/earthquakes/eqshow/647003_06.htm
Damage to the Intercontinental Hotel during Mexico City's 1985 earthquake was
severe even though the building was relatively new
http://www.calstatela.edu/dept/geology/G351.htm
Building Design
After the earthquake in Mexico City, Mexican officials adopted a new design that can protect the buildings from
earthquakes. This design was developed by some engineers at the University of California at Berkeley.
Looking at the diagram below you can see that the braces form an X which are anchored in concrete blocks at
the base and on the roof of the building.
In diagram A we have conventional steel bracing. Under the stress of the earthquake one of the braces collapses
under the stress. If all the braces begging to snap then the structural integrity of the building fails.
Now in diagram B, the engineers at Berkely used a hydraulic jack to pull or stretch the rods. Once the rods are
prestressed they can now be anchored to the base and to the roof of the building. The braces now have some
room to contract thereby strengthening the structural integrity of the building.
Northridge Earthquake, 1994
Southern California, USA
6.7 Magnitude
most houses were wooden and did not collapse
www.survival1.com/
Problems for Building Structures when Seismic Waves pass
For tall buildings the top may sway in the opposite direction as the base
Buildings in close proximity with one another may collide do to differing phase motions.
Changing types of wave motion cause damage.
Buildings with different resonant frequencies will be affected differently by passing
seismic waves depending on the wave frequency.
http://www.mines.utah.edu/~schuster/gg103/res/resonance.html
http://www.scarborough.k12.me.us/wis/teachers/dtewhey/webquest/nature/earthquake_images.htm
Loma Prieta Earthquake, 1989
San Francisco Bay, California
7.1 magnitude
• Many homes were damaged because of old
construction- unreinforced bricks and mortar
• Many building and homes were built on were
unconsolidated flood plain sedimentary land (In
contrast, nearby sections of the city experienced
only minor damage. These areas contain sturdy
wood frame houses built on relatively stable
marine terraces.)
•http://www.es.ucsc.edu/~es10/fieldtripEarthQ/Damage2.html
As the second story of this building collapsed, its facade fell into the street, knocking
down the tree which in turn damaged the car. This building in downtown was one of the
heavily damaged buildings situated on the unconsolidated flood plain sediments of the
San Lorenzo River.
•http://pubs.usgs.gov/dds/dds-29/
An automobile lies crushed under the third story of this apartment building in
the Marina District. The ground levels are no longer visible because of
structural failure and sinking due to liquefaction
•http://pubs.usgs.gov/dds/dds-29/
Collapsed brickwork from a corner apartment building, Marina
District.
•http://pubs.usgs.gov/dds/dds-29/
Oakland Support failure
•http://pubs.usgs.gov/dds/dds-29/
•http://pubs.usgs.gov/dds/dds-29/
Oakland Bridge failure
•http://pubs.usgs.gov/dds/dds-29/
•http://pubs.usgs.gov/dds/dds-29/
Structural Design Project
Part One: In collaboration with Science 7 use K’Nex to build a 3+ story
structure and demonstrate it’s ability to make it through an
earthquake. Keep notes and drawings, make your hypothesis,
itemize materials. Group work.
Make revisions and demonstrate renewed ability to make it
through an earthquake.
Part Two: Design an earthquake resistant 3+ story structure
constructed using 50% recycled and 50% new materials. As in
Part One, demonstrate it’s ability to make it through an
earthquake. Keep notes and drawings, make your hypothesis,
itemize materials. Contract project as a group or as individual
work.
Make revisions and demonstrate renewed ability to make it
through an earthquake.
Due date Part One:
Due date Part Two:
All drawings, material critique, hypothesis and conclusions concerning
earthquake structural engineering as it relates to architectural
design.