Lec02 Earthquake Damage to Concrete Structure (Earthquake Engineering هندسة الزلازل & Assc.Prof Nasser El-Shafey)

EARTHQUAKE
Damage To
Concrete Structure
Prepared by :
Assc. Prof Nasser El-Shafey
2016- 2017

Introduction
 Earthquakes constitute one of the worst natural
hazards which often turn into disaster causing
widespread destruction of cities, fires caused by
downed power lines and ruptured of mains gas
tubes, and losses of human life.
 Earthquake vary upon it’s magnitude and intensity.
 Earthquake is movement of the rocks in Earth’s
crest as result of a sudden release of energy in the
Earth's crust.
 After main shock, an aftershock is in same region
but always of a smaller magnitude.

The boundaries between moving tectonic plates, relative
motion between plates leads to increasing stress until
stress rises and breaks, suddenly allowing
• sliding over fault
• Releasing stored energy which creates seismic waves
causing the main shock.
 When earthquake waves moves offshore in the Ocean it
can cause Tsunami which can cross an ocean and cause
extensive damage to coastal regions.
 Earthquakes magnitude and intensity, is measured on a
numerical scale. Scale, 4 or less is not noticeable, For
every unit increase in magnitude, there is roughly a great
increase in energy released and magnitude 7 (or more)
causes damage over a wide area.

Causes of Earthquakes
Tectonic Earthquakes
 Caused by the sudden dislocation of large rock masses
along geological faults within the earth's crust.
 The Earth is formed of several layers that have very
different physical and chemical properties. The outer
layer, which averages about 50 miles thick in thickness,
consists of about a dozen large, irregularly shaped
plates that slide over, under and past each other on top
of inner layer .
 Most earthquakes occur at the boundaries where the
plates meet ..

‫نظري‬‫ة‬‫نشأة‬‫الزالزل‬
‫ت‬‫ت‬‫كان‬‫األرض‬‫ر‬ ‫تا‬‫ت‬ ‫ك‬ ‫ا‬‫ن‬‫ن‬‫تائ‬‫ت‬ ‫نا‬‫م‬‫ت‬‫ت‬ ‫ا‬ ‫تؤجسا‬‫ت‬‫نت‬ ‫تن‬‫ت‬‫من‬‫ت‬‫ت‬‫الكواك‬ّ‫تو‬‫ت‬‫ك‬ ّ‫تر‬‫ت‬‫د‬ ‫تا‬‫ت‬‫وحٌنم‬ ،ً ‫تا‬‫ت‬‫الم‬ ‫ا‬ ‫ت‬‫ت‬‫الغ‬‫ت‬‫ت‬‫ل‬ ‫تن‬‫ت‬‫وا‬
ً ‫السوا‬ ‫ا‬ ‫الغ‬‫ت‬ ‫دا‬ ‫المفروبت‬ ‫الئاراٌت‬ ‫اللتةد‬ ‫الطدقت‬ ‫ن‬ َّ‫جكو‬ ‫الدروّة‬ ‫زٌاّة‬ ‫ومع‬ ،‫القتترة‬‫دتاط‬ ‫لكت‬ ،
‫األرض‬‫لسارة‬ ‫عةى‬ ‫وٌحجوى‬ ، ‫اآل‬ ‫حجى‬ ‫ا‬‫ن‬‫ن‬‫ائ‬ ‫ظل‬ّ‫مف‬ً‫بت‬ ‫اللئوراللتةد‬ ‫جآكل‬ ‫عةى‬ ‫ٌفمل‬‫القتترة‬
، ‫دمرورالوقت‬ ّ‫جتزّا‬ ‫لةغاٌت‬ ‫عظٌمت‬ ‫وطاقا‬ ‫دإاساّا‬ ‫تحنسا‬ ‫أو‬ ‫وجحمٌةسا‬ ‫اللةد‬‫والقتترة‬‫نت‬ ّ‫مكو‬ ‫تسا‬ ‫نف‬
‫م‬ ‫قارة‬ ‫منسا‬ ‫لوح‬ ‫كل‬ ‫وٌحمل‬ ،‫ا‬ّ‫ن‬ّ‫ا‬ ‫ق‬ ‫الفم‬ ٌ‫اللئر‬ ‫األلواح‬ ‫م‬ ‫ماموع‬ ‫م‬‫القارا‬‫وجحّث‬ ،‫أكثر‬ ‫أو‬
‫ٌطةتا‬ ً‫والجت‬ ،‫دفتض‬ ‫متع‬ ‫دفضتسا‬ ‫األلتواح‬ ‫وتن‬ ‫الجقتاأل‬ ‫منتاطا‬ ً‫بت‬ ً‫ت‬ ‫ا‬ ‫أ‬ ‫دتتكل‬ ‫التتح‬ ‫أو‬ ‫الجحمٌتل‬ ٌ‫عمة‬
‫الفةماأل‬ ‫عةٌسا‬‫اللّوع‬‫الحامة‬ ‫األلواح‬ ‫ودّاٌا‬ ‫نساٌا‬ ّّّ‫جح‬ ً‫الج‬ ‫الفوالا‬ ‫أو‬‫لةقارا‬‫التح‬ ٌّ‫ٌز‬ ‫وحٌنما‬ ،
‫باتؤة‬ ‫الطاقت‬ ‫وتن‬ ‫تراح‬ ‫ا‬ ‫الطت‬ ‫توى‬ ‫تفسا‬ ‫دو‬ ‫ٌكو‬ ‫ال‬ ‫االحجمال‬ ‫اللئورعةى‬ ‫ون‬ ‫قّرة‬ ‫عةى‬ ‫الضغط‬ ‫أو‬
‫لئور‬ ‫وجئجترا‬ ، ‫االجااوتا‬ ‫امٌتع‬ ً‫جنجتترب‬ ‫قوٌت‬ ‫حرك‬ ‫مواا‬ ‫لورة‬ ً‫ب‬ٌ‫األرضت‬ ‫القتترة‬‫وجافةستا‬ ،
‫عةتى‬ ‫نتتؤ‬ ‫نلك‬ ‫ضوأل‬ ً‫ب‬ ،‫المفروا‬ ‫النحو‬ ‫عةى‬ ‫جسجزوجرجاا‬‫األرض‬‫الضتفٌف‬ ‫المنتاطا‬ ‫مت‬ ‫ماموعت‬
ً‫ب‬ٌ‫األرض‬ ‫القترة‬‫ّائةستا‬ ‫ٌفجمتل‬ ‫عمتا‬ ‫األرض‬ ‫لستا‬ ‫ئ‬ ‫م‬ ‫جنفس‬ ‫مئارج‬ ‫أو‬ ً‫الزلزال‬ ‫جفجدرمراكزالنتاط‬
‫عةٌسا‬ ‫وٌطةا‬ ،‫ا‬ ‫نط‬ ‫ل‬ ‫جحجاج‬ ‫قةق‬ ‫طاق‬ ‫م‬"‫الزالزل‬ ‫أحزم‬."
The earth crust is cracked into seven large and many other smaller
plates, averaging about 50 miles thick. They move (only 2- inches per
year), and depending on direction of that movement, forming deep
ocean trenches, mountains, volcanoes, and generating earthquakes.

 A fault is a fracture within some particular rocky mass within
the earth's crust.
 The depth and length of faults vary greatly in length from few
meters to many kilometers .
 Earthquakes caused by active faults that is, faults along which
two sides of fracture move with respect to each other.
a) Normal faults These occur in response to pulling or tension:
the overlying block moves down the dip of the fault plane.
b) Thrust (reverse) faults
These occur in response to squeezing or compression ,the
overlying block moves up the dip of the fault plane.
c) Strike‐slip (lateral) faults
These occur in response to either type of stress: the blocks move
horizontally past one another .

Earthquake Focus
The point on the fault where rupture initiates is referred to
as the focus or hypocenter of an earthquake.
 The hypocenter of an earthquake is described by its depth
in kilometers, location in latitude, its date and of occurrence
and its time and magnitude.
The epicenter is the point on the earth’s surface directly
above the hypocenter

Earthquake damages in the
epicenter area
Earthquake damages 100 km from
the epicenter
Earthquake damages 200 kilometers
from the epicenter: Left part of the
house completely destroyed, first floor
of the right part heavily damaged

Love waves
Rayleigh waves
Surface Waves
Surface waves travels parallel to the earth’s surface and
these waves are slowest and most damaging. Surface
wave are divided into following types:

Earthquakes classified as:
Deep focus earthquakes: Focal depth > 300 Km
Intermediate focus earthquakes: 300 Km >Focal depth > 70 Km
Shallow focus earthquakes : Focal depth < 70 Km
Earthquake effects on buildings depend on:
 Mass of structure
 Stiffness of structure
 Ductility of structures
 Foundation type
 Soil conditions
 Earthquake zone

 Loss of life and property.
 Damage to transport system i.e. roads, railways, highways,
airports, marine.
 Damage to infrastructure.
 Chances of Floods – Develop cracks in Dams.
 Communications such as telephone wires are damaged.
 Water pipes, sewers are disrupted.
 Economic activities like agriculture, industry, transport are
severely affected.
Effect Of Earthquake

Earthquake Prediction
 Earthquake prediction usually defined as specification of
the time, location , and magnitude of a future earthquake
within stated limits.
But some evidence of upcoming Earthquake are following:
 Unusual animal behavior.
 Water level in wells.
 Large scale of fluctuation of oil flow from oil wells.
 Foreshocks or minor shocks before major earthquake.
 Temperature change.
 Uplifting of earth surface.
 Change in seismic wave velocity.

Structural Damage
Structural damage does not usually occur until the magnitude
approaches 5.0. Most structural damage during earthquakes is
caused by the failure of the surrounding soil or from strong
shaking
levels of damage

‫الشدة‬‫الوصف‬‫القوة‬(‫ريختر‬ ‫مقياس‬)
1
‫أاسزة‬ ‫سا‬ ‫ججح‬ ،‫القٌاس‬ ‫أاسزة‬ ّ‫حّو‬ ‫ضم‬
‫موغراا‬ ٌ ‫ال‬
-
) -2‫ضعيفة‬(‫قةٌةو‬ ‫أناس‬ ‫دسا‬ ‫ٌتفر‬3.5
) -3‫قليلة‬(‫دسا‬ ‫ٌحس‬ ّ‫ٌكا‬ ‫ال‬4.2
-4)‫معتدلة‬(‫المتاة‬ ‫دسا‬ ‫ٌحس‬4.3
)-5‫قوية‬‫بعض‬‫الشيء‬(‫الناس‬ ‫دفض‬ ‫جٌقظ‬ ٌ4.8
)-6‫قوية‬(‫األتٌاأل‬ ‫قط‬ ‫وج‬ ‫األتاار‬ ‫ججرنح‬4.8 - 5.4
)-7‫قوية‬‫جدا‬(‫عا‬ ‫الننار‬-‫الاّرا‬ ‫ججتقا‬5.5 - 6.1
) -8‫هدامة‬(‫المجحرك‬ ‫ٌارا‬ ‫ال‬ ‫ججؤثر‬6.2 - 6.8
)-9‫مخربة‬(‫األرض‬ ‫وججتقا‬ ‫الدٌو‬ ‫دفض‬ ‫قط‬ ‫ج‬6.9
)-10‫كارثية‬(‫انسٌارا‬ ‫وجحّث‬ ‫األرض‬ ‫ججفجح‬7 - 7.3
)-11‫كارثية‬‫للغاية‬(‫الدناٌا‬ ‫دفض‬ ‫جدقى‬7.4 - 8.1
)-12‫مفجعة‬(‫جا‬ ‫ّمار‬8.1 - 8.9‫ّرا‬ ‫أقلى‬
‫الزالزل‬ ‫مقاييس‬

Magnitude of an earthquake (M)
Richter scale M= log (A / Ao)
Where:
A is the recorded amplitude measured by a
standard torsional seismometer for a given
earthquake at a given epicentral distance.
Ao is the standard amplitude for reference
earthquake at the same distance.
The relationship between energy released E
and Richter scale M is:
For example M 8 earthquake releases 1000 times the energy of M 6
earthquake

‫الزالزل‬ ‫أهم‬ ‫بعض‬ ‫تاريخ‬(‫االخيرة‬ ‫السنوات‬ ‫فى‬)
‫زلزال‬‫الٌادا‬ ‫ترا‬ ‫تمال‬2011311‫قوج‬8.9‫رٌئجر‬ ‫مقٌاس‬ ‫عةى‬ ‫ّراا‬.
‫كانجردري‬ ‫زلزال‬(‫نٌوزلنّا‬)4/10/2010‫قوج‬7.4‫رٌئجر‬ ‫مقٌاس‬ ‫عةى‬ ‫ّراا‬.
ً‫جتٌة‬ ‫زلزال‬2010‫قوج‬8.8‫مقٌاس‬ ‫عةى‬ ‫ّراا‬‫رٌئجر‬
ً‫واٌج‬ ‫زلزال‬2010‫قوج‬7ً‫حوال‬ ‫قجل‬ ‫رٌئجر‬ ‫مقٌاس‬ ‫عةى‬ ‫ّراا‬230ّ‫وتر‬ ‫تئص‬ ‫الا‬
‫تئص‬ ‫مةٌو‬ ‫م‬ ‫أكثر‬.
‫زلزال‬‫السنّي‬ ‫المحٌط‬26‫مدر‬ ٌّ2004‫موا‬ ‫أتسر‬ ‫أعقد‬ ‫الني‬ً‫ونام‬ ‫ج‬‫ضرد‬ ‫حٌث‬
ٌّّ‫الف‬ ‫واحل‬‫م‬‫الّول‬‫حٌث‬‫ا‬‫الزلزال‬‫ٌفجدر‬‫دؤن‬‫وأ‬ ‫أ‬ ّ‫أح‬ٌ‫الطدٌف‬ ‫الكوارث‬‫ا‬ ‫اإلط‬ ‫عةى‬
.230000‫زلزال‬ ‫قجل‬‫كتمٌر‬2006ً‫حوال‬ ٌ‫ب‬ ‫قجل‬79‫تئص‬ ‫ألا‬.
‫زلزال‬‫ٌم‬ ‫الح‬‫المغر‬‫بدراٌر‬2004‫قوج‬ ‫دةغ‬ ،6,5ً‫حوال‬ ‫وباة‬ ‫ع‬ ‫فر‬ ‫وأ‬ ‫رٌئجر‬ ‫دمقٌاس‬
600‫قجٌل‬.
‫زلزال‬‫ر‬ ‫الازا‬05/2003‫دؤكمةسا‬ ٌ‫الوال‬ ‫ّمر‬-(‫األلنا‬ ٌ‫وال‬)1980ٌ‫الوال‬ ‫ّمر‬‫دا‬‫أكمةسا‬.

‫زلزال‬ٌ‫الل‬‫دؤكمةسا‬ ‫مٌّن‬ ‫ّمر‬ ٌ‫ح‬ ‫زلزال‬ ّ‫ات‬ ‫وكا‬5/3/2008.
‫ماٌو‬1998:ً‫ب‬ ‫زلزال‬‫جا‬ ‫أبغان‬‫تئص‬ ‫آالا‬ ‫أردف‬ ‫ٌقجل‬.
‫ماٌو‬1995:ٌ‫ائال‬ ‫ازٌرة‬ ‫ٌضر‬ ‫الّرا‬ ‫ونلا‬ ‫ّراا‬ ‫دع‬ ‫دقوة‬ ‫زلزال‬
‫ن‬‫ا‬‫ألف‬ ‫وٌقجل‬ ٌ ‫الرو‬‫فم‬ ‫وج‬‫ا‬‫ن‬‫ا‬‫تئل‬ ٌ‫وثمان‬ ‫ف‬ ‫وج‬.
‫أكجودر‬1992:‫ٌضر‬ ‫الّرا‬ ‫اعتار‬ ً‫وثمان‬ ‫ّراا‬ ‫ئمس‬ ‫دقوة‬ ‫زلزال‬‫ملر‬
‫كا‬ ‫تئص‬ ‫آالا‬ ‫ث‬ ‫ث‬ ‫م‬ ‫أكثر‬ ‫والاد‬ ٌ‫دف‬ ‫و‬ ‫ثما‬ ‫ث‬ ‫نحو‬ ‫مقجل‬ ‫اللى‬ ‫وٌإّي‬
‫الزلزال‬ ‫مركز‬‫غر‬ ‫انو‬‫القاورة‬‫م‬ ‫دالقر‬‫الفٌو‬‫و‬‫الاٌزة‬‫دفنا‬ ‫د‬ ِ‫ُر‬‫ض‬ ً‫الج‬.
‫دجمدر‬1985:‫عترة‬ ‫وٌقجل‬ ً‫المدان‬ ‫ٌّمر‬ ٌ‫ٌك‬ ‫المك‬ ‫الفالم‬ ‫ٌسز‬ ‫عنٌا‬ ‫زلزال‬
‫آالا‬‫تئص‬
ً‫ب‬1976:‫أرواح‬ ‫عةى‬ ‫أجى‬ ‫زلزال‬ ‫دففل‬ ‫انقاض‬ ‫اللى‬ ٌ‫اللٌن‬ ‫جانغتا‬ ‫مٌّن‬ ‫جحول‬
‫م‬ ‫ئم‬‫ا‬‫ألا‬‫تئص‬
ً‫ب‬1960:‫قوج‬ ‫ودةغ‬ ،ً‫جتٌة‬ ً‫ب‬ ‫ال‬ ً‫الفالم‬ ‫النطاا‬ ‫عةى‬ ‫زلزال‬ ‫أقوى‬9.5
‫مقٌاس‬ ‫عةى‬‫رٌئجر‬‫وا‬ ‫ع‬ ‫أزال‬ ّ‫وق‬ ،‫األرض‬‫الدتر‬ ‫م‬ ‫اآلالا‬ ‫وقجل‬ ‫دكامةسا‬ ‫قرى‬.

How Building Affected by Earthquakes
•As building, experiences acceleration, inertia force is generated.
Newton’s Second Law of Motion,
F inertia= Mass (M) x Acceleration(a).
•As ground under a building shakes sideways, horizontal accelerations transfer
up through the superstructure and generate inertia forces throughout it.

The greater the mass (weight of building),the greater
the internal inertia forces generated, increasing the
possibility of columns being displaced, and/or buckling
under vertical load.
 Lightweight construction with less mass is typically an
advantage in seismic design.
All buildings, have a natural or fundamental period at
which they vibrate by a shock.
The natural period is a primary consideration for seismic
design, If the period of the shock wave and the natural
period of the building coincide, then the building will
"resonate" and its vibration will increase or "amplify"
several times

•Inertia forces act on every item and every component.
Just as gravity force except that it acts horizontally.

Gravity forces acting can be assumed to act at its center
of mass (COM), so can inertia force on any item be
considered to act at the same point.

Difference Between Wind Force And Earthquake Force
■Wind force is external to a building, while earthquake
force is an internal force.
■Its magnitude and center of loading is determined by the
surface area upon which it acts.
■Like inertia forces, wind loading is dynamic, but whereas peak
earthquake forces act for just fractions of a second, the duration
of a strong wind gust in the order of several seconds.
■Inertia forces are cyclic – they act to-and-fro.

 Tall buildings will under go
several modes of vibration, but
for seismic purposes (except for
very tall buildings) the
fundamental period or first
mode is usually the most
significant.

Stiffness deformation
Stiffness is the quantity that relates forces to structural
deformations. OR it can defined as the force needed to make
deformation equal ONE unit. It is equal to the slope of the load-
deflection relationship
A key structural principle is that
structural elements resist force in
proportion to their stiffness.
➢Where more than one member
resists forces the stiffer member the
more force it resists.
➢Stiffness is proportional to the
moment of inertia of a member (I).

In reinforced concrete, due to cracking of concrete and yielding
of steel , the stiffness of R.C member is not constant
I = b.d 3 /12
(b) is the member width or breadth,
and (d) its depth measured parallel
to the direction of the force being
resisted. Since both walls have the
same width (b), their respective
stiffness is proportional to 13 and
23; that is, 1 and 8. The slender
wall, therefore, resists 1/9th or 11
per cent of the force and the longer
wall 8/9th or 89 percent.

Ductility:
Ductility is the characteristic of a material to bend, flex, or
move, but fails only after considerable deformation has
occurred. Non-ductile materials (such as reinforced
concrete) fail abruptly by crumbling. Good ductility can be
achieved with carefully detailed joints.

HOW TO INCREASE DUCTILTY?
Ductility of a section can be increased by :
 Increase the % of the tension steel.
 Increase the % of compression steel.
 Increase in compressive strength of concrete.
 Increase in transverse shear reinforcement.
 Effective lateral confinement of concrete increases the
ductility of columns. The confinement takes the form of
stirrups or spiral reinforcement.
 The use of compression reinforcement increases
the ductility of flexural members.

1. Design the structure for a small earthquake force but
provide it with tools to have enough ductility
(economic design).
2.Design the structure for a large earthquake force without
the need to be ductile (uneconomic design).
■For R/C members subjected to pure bending or combined
bending and low levels of axial load, ductility is ensured
through having the section under-reinforcement (As<A smax)
■For R/C members subjected to high level of axial load,
ductility is ensured through having the section well confined
by using closed stirrups

STRENGTH
A quantity that indicates the
maximum resistance member
can provide against loads.
Shear walls which are strong
only in the direction of their
lengths, horizontal strength
should be provided in both the
x and y directions.

Earthquake zoning
The earthquake zoning map divides Egypt into 5 Seismic
Zones Based on the observations of the affected area due
to Earthquake
Zone - II: This is said to be the least active seismic zone.
Zone - III: It is included in the moderate seismic zone.
Zone - IV: This is considered to be the high seismic zone.
Zone - V: It is the highest seismic zone.

■ Failure of Slopes ■ Land Slide

Fault displacement at site of structure

■ Building Collapse ■ Bridge Collapse

EARTHQUAKE HAZARDS
■ Specific Failures
•
Collapse of the first storey and damage
due to pounding between adjacent
buildings during the Kocaeli earthquake,
Turkey, August 17, 1999,Magnitude 7.4
Collapse of a high-rise building because
of failure of the columns at the first storey
during the Chi-Chi earthquake, Taiwan,
September 20, 1999, Magnitude 7.6

EARTHQUAKE HAZARDS
May 1 2 China Earthquake
Date May 12, 2008, 14:28
Magnitude: 8.0 Richter Scale Earthquake
Location : Sichuan,
Some counties completely wiped off the map
More than 11M people Displaced

Lec02 Earthquake Damage to Concrete Structure (Earthquake Engineering هندسة الزلازل & Assc.Prof Nasser El-Shafey)

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