Download earthquake resistent..

EARTHQUAKE RESISTENT BUILDING CONSTRUCTION
1. Explain with diagram structure of earth?
he average density of Earth is 5,515 kg/m3. Since the average density of surface material is only
around 3,000 kg/m3, we must conclude that denser materials exist within Earth's core. Further
evidence for the high density core comes from the study of seismology.
Seismic measurements show that the core is divided into two parts, a solid inner core with
a radius of ~1,220 km[2] and a liquid outer core extending beyond it to a radius of ~3,400 km. The
solid inner core was discovered in 1936 by Inge Lehmann and is generally believed to be
composed primarily of iron and some nickel. In early stages of Earth's formation about 4.5 billion
(4.5×109) years ago, melting would have caused denser substances to sink toward the center in a
process called planetary differentiation (see also the iron catastrophe), while less-dense materials
would have migrated to the crust. The core is thus believed to largely be composed of iron (80%),
along with nickel and one or more light elements, whereas other dense elements, such
as lead and uranium, either are too rare to be significant or tend to bind to lighter elements and
thus remain in the crust (see felsic materials). Some have argued that the inner core may be in
the form of a single ironcrystal.[3][4]
On August 30, 2011, Professor Kei Hirose, professor of high-pressure mineral physics and
petrology at the Tokyo Institute of Technology, became the first person to recreate conditions
found at the earth's core under laboratory conditions, subjecting a sample of iron nickel alloy to
the same type of pressure by gripping it in a vice between 2 diamond tips, and then heating the
sample to approximately 4000 Kelvins with a laser. The sample was observed with x-rays, and
strongly supported the theory that the earth's inner core was made of giant crystals running north
to south.[5]
The liquid outer core surrounds the inner core and is believed to be composed of iron mixed with
nickel and trace amounts of lighter elements.
Recent speculation suggests that the innermost part of the core is enriched in gold, platinum and
other siderophile elements.[6]
The matter that comprises Earth is connected in fundamental ways to matter of
certain chondrite meteorites, and to matter of outer portion of the Sun.[7][8] There is good reason to
believe that Earth is, in the main, like a chondrite meteorite. Beginning as early as 1940,
scientists, including Francis Birch, built geophysics upon the premise that Earth is like ordinary
chondrites, the most common type of meteorite observed impacting Earth, while totally ignoring
another, albeit less abundant type, called enstatite chondrites. The principal difference between
the two meteorite types is that enstatite chondrites formed under circumstances of extremely
limited available oxygen, leading to certain normally oxyphile elements existing either partially or
wholly in the alloy portion that corresponds to the core of Earth.
Dynamo theory suggests that convection in the outer core, combined with the Coriolis effect,
gives rise to Earth's magnetic field. The solid inner core is too hot to hold a permanent magnetic
field (seeCurie temperature) but probably acts to stabilize the magnetic field generated by the
liquid outer core. The average magnetic field strength in the Earth's outer core is estimated to be
25 Gauss, 50 times stronger than the magnetic field at the surface.[9][10]
Recent evidence has suggested that the inner core of Earth may rotate slightly faster than the
rest of the planet.[11] In August 2005 a team of geophysicists announced in the
journal Science that, according to their estimates, Earth's inner core rotates approximately 0.3 to
0.5 degrees per year relative to the rotation of the surface.[12][13]
2. Write down the properties of P-waves and secondary waves.
Seismic wave are waves of energy that travel through the earth, and are a result of
an earthquake, explosion, or a volcano that imparts low-frequency acoustic energy. Many other
natural and anthropogenic sources create low amplitude waves commonly referred to as ambient
vibrations. Seismic waves are studied by geophysicists called seismologists . Seismic wave fields
are recorded by a seismometer, hydrophone (in water), or accelerometer.
The propagation velocity of the waves depends on density and elasticity of the medium. Velocity
tends to increase with depth, and ranges from approximately 2 to 8 km/s in the Earth's crust up to
13 km/s in the deep mantle.
Earthquakes create various types of waves with different velocities; when reaching seismic
observatories, their different travel time help scientists to locate the source of the
earthquake hypocenter. In geophysics the refraction or reflection of seismic waves is used for
research into the structure of the Earth's interior, and man made vibrations are often generated to
investigate shallow, subsurface structures.
Types of seismic waves
There are two types of seismic waves, body wave and surface waves. Other modes of wave
propagation exist than those described in this article, but they are of comparatively minor
importance for earth-borne waves, although they are important in the case of asteroseismology.
[edit]Body
waves
Body waves travel through the interior of the Earth. They create raypaths refracted by the
varying density and modulus (stiffness) of the Earth's interior. The density and modulus, in turn,
vary according to temperature, composition, and phase. This effect is similar to
the refraction of light waves.
[edit]Primary waves
Main article: P-wave
Primary waves (P-waves) are compressional waves that are longitudinal in nature. P waves are
pressure waves that travel faster than other waves through the earth to arrive at seismograph
stations first hence the name "Primary". These waves can travel through any type of material,
including fluids, and can travel at nearly twice the speed of S waves. In air, they take the form of
sound waves, hence they travel at the speed of sound. Typical speeds are 330 m/s in air,
1450 m/s in water and about 5000 m/s in granite.
[edit]Secondary waves
Main article: S-wave
Secondary waves (S-waves) are shear waves that are transverse in nature. These waves arrive
at seismograph stations after the faster moving P waves during an earthquake and displace the
ground perpendicular to the direction of propagation. Depending on the propagational direction,
the wave can take on different surface characteristics; for example, in the case of horizontally
polarized S waves, the ground moves alternately to one side and then the other. S waves can
travel only through solids, as fluids (liquids and gases) do not support shear stresses. S waves
are slower than P waves, and speeds are typically around 60% of that of P waves in any given
material.
3. What are the effects of earthquake?
An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release
of energy in the Earth's crust that createsseismic waves. The seismicity, seismism or seismic
activity of an area refers to the frequency, type and size of earthquakes experienced over a
period of time. Earthquakes are measured using observations from seismometers. The moment
magnitude is the most common scale on which earthquakes larger than approximately 5 are
reported for the entire globe. The more numerous earthquakes smaller than magnitude 5 reported
by national seismological observatories are measured mostly on the local magnitude scale, also
referred to as the Richter scale. These two scales are numerically similar over their range of
validity. Magnitude 3 or lower earthquakes are mostly almost imperceptible and magnitude 7 and
over potentially cause serious damage over large areas, depending on their depth. The largest
earthquakes in historic times have been of magnitude slightly over 9, although there is no limit to
the possible magnitude. The most recent large earthquake of magnitude 9.0 or larger was a 9.0
magnitude earthquake in Japan in 2011 (as of March 2011), and it was the largest Japanese
earthquake since records began. Intensity of shaking is measured on the modified Mercalli scale.
The shallower an earthquake, the more damage to structures it causes, all else being equal.[1]
At the Earth's surface, earthquakes manifest themselves by shaking and sometimes
displacement of the ground. When the epicenter of a large earthquake is located offshore, the
seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger
landslides, and occasionally volcanic activity.
In its most general sense, the word earthquake is used to describe any seismic event — whether
natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly
by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine
blasts, and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter.
The epicenter is the point at ground level directly above the hypocenter.
Earthquake fault types
Main article: Fault (geology)
There are three main types of fault that may cause an earthquake: normal, reverse (thrust) and
strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along
the fault is in the direction of dip and movement on them involves a vertical component. Normal
faults occur mainly in areas where the crust is beingextended such as a divergent boundary.
Reverse faults occur in areas where the crust is being shortened such as at a convergent
boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally
past each other; transform boundaries are a particular type of strike-slip fault. Many earthquakes
are caused by movement on faults that have components of both dip-slip and strike-slip; this is
known as oblique slip.
4. What is box action? How does it help in transfer of forces from one wall to
another?
5. Give the categories of buildings as per IS:4326:1993.
6. What are the main weaknesses of RC frame building?
7. What is special confining reinforcement? Where should we provide?\
Previously derived stress‐strain relationships for compressed concrete confined by various quantities and
arrangements of transverse reinforcement are used in cyclic moment‐curvature analyses of a range of
reinforced concrete columns to derive design charts. The design charts permit the enhanced flexural
strength of confined columns to be obtained. They also permit the quantities of transverse reinforcement
required to achieve particular curvature‐ductility factors in the potential plastic‐hinge regions of reinforced
concrete columns to be determined. The column section is considered to have reached its available ultimate
curvature when either the moment resisted has reduced to 80% of the ideal flexural strength, or the strain
energy absorbed in the transverse reinforcement has reached its strain energy absorption capacity, or when
the logitudinal steel has reached its limiting tensile or compressive strain, whichever occurs first. Refined
design equations to determine the quantities of transverse reinforcement required for specified ductility
levels are derived on the basis of the design charts. The equations are an improvement on the current
provisions of concrete design codes. The reasons for quark confinement are somewhat complicated;
no analytic proof exists that quantum chromodynamics should be confining, but intuitively,
confinement is due to the force-carrying gluons having color charge. As any two electricallycharged particles separate, the electric fields between them diminish quickly, allowing (for
example) electrons to become unbound from atomic nuclei. However, as two quarksseparate, the
gluon fields form narrow tubes (or strings) of color charge, which tend to bring the quarks together
as though they were some kind of rubber band. This is quite different in behavior from electrical
charge. Because of this behavior, the color force experienced by the quarks in the direction to
hold them together, remains constant, regardless of their distance from each other, [3][4] at around
10,000 Newtons.
When two quarks become separated, as happens in particle accelerator collisions, at some point
it is more energetically favorable for a new quark–antiquark pair to spontaneously appear, than to
allow the tube to extend further. As a result of this, when quarks are produced in particle
accelerators, instead of seeing the individual quarks in detectors, scientists see "jets" of many
color-neutral particles (mesons and baryons), clustered together. This process is
called hadronization, fragmentation, or string breaking, and is one of the least understood
processes in particle physics.
The confining phase is usually defined by the behavior of the action of the Wilson loop, which is
simply the path in spacetime traced out by a quark–antiquark pair created at one point and
annihilated at another point. In a non-confining theory, the action of such a loop is proportional to
its perimeter. However, in a confining theory, the action of the loop
8. What is the importance of safety operations in rescuer operation?
9. The crime of rescue has four elements. First, the arrest of a prisoner must be lawful.
Second, the prisoner must be in actual custody, that is, in the personal custody of an
officer or in a prison or jail. Third, at common law and under some statutes, the rescue
must be forcibly made. Fourth, the prisoner must actually escape. At common law, the
person guilty of rescue is guilty of the same grade of offense, whether felony or
misdemeanor, as the person who is rescued.
10. Under federal law, rescue of a prisoner held in federal custody is a felony. As defined by
18 U.S.C.A. § 752 (1994), rescue is the crime of instigating or assisting escape from
lawful custody. The law takes its punishment provisions from the federal statute (18
U.S.C.A. § 751 [1994]) that makes it unlawful for a prisoner to escape from a place of
confinement: conviction carries fines of up to $5,000 and imprisonment of up to five years
for the rescue of an adult, and equivalent fines and imprisonment of up to a year for the
rescue of a minor. Thus, like the common-law definition, the same punishment applies to
a person aiding an escape as that given to the person escaping.
11. Criminal cases involving rescue can be dramatic. In the 1933 case of Merrill v. State, 42
Ariz. 341, 26 P. 2d 110, Herbert Merrill appealed his conviction for attempting to rescue
Albert De Raey from the Maricopa County, Arizona, jail. On January 10, 1933, Merrill
brought acid to the jail at De Raey's request so that De Raey could use it to cut through
the bars on his jail cell. Merrill was subsequently convicted of attempting to rescue under
section 4537 of Arizona's Revised Code of 1928. On appeal, however, the appellate
court reversed the conviction: it found that although Merrill had apparently assisted in an
escape attempt, he had not forcibly attempted to effect a rescue. Thus he had been
improperly charged, the conviction could not stand, and the case was sent back to the
lower court.
12. In 1989 a California case raised the issue of when rescue is defensible. On November 5,
1986, Ronald J. McIntosh landed a helicopter on the grounds of the Federal Correctional
Institution at Pleasanton, California, and then flew off with his girlfriend, Samantha D.
Lopez, who was being held as a prisoner there. McIntosh was later convicted of aiding
Lopez's escape and two other felonies; Lopez was convicted of escape. In a joint appeal,
they alleged that their offenses were necessary to save Lopez's life because she had
been threatened by prison officials and was in immediate danger (United States v. Lopez,
885 F. 2d 1428 [9th C.C.A. 1989]). In fact, such a defense—called a necessity defense—
can excuse the otherwise criminal act of escape. The appeal alleged that the trial court
had improperly instructed the jury as to the availability of this defense to both defendants.
However, in upholding their convictions, the appellate court found that the trial judge
committed no error in the instructions with respect to Lopez, and only a Harmless
Error where McIntosh was concerned.
13. Under admiralty and maritime law, rescue has another definition entirely. It means
recovering goods that have been forcibly taken by one vessel from another. The property
in question is referred to as a prize, and its rescue may be effected by reclaiming the
property with force or by escaping. Generally, such actions occur when two belligerent
powers clash, either in a limited dispute or at war.