About Eq Engineering

7/30/2019 About Eq Engineering

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ENGINEERING:Engineering is the application of scientific and technical knowledge to solve human

problems. Engineers use imagination, judgment and reasoning to apply science, technology,mathematics, and practical experience. The result is the engineering design, production, andoperation of useful objects or processes.

Engineering has several major fields, of which 19 major ones according to the NationalSociety of Professional Engineers are:

Aerospace engineering

Agricultural engineering

Biomedical engineering

Chemical engineering

Civil engineering (general & structural)

Computer engineering

Control Systems Electrical & electronic engineering

Environmental engineering

Fire protection engineering

Geotechnical engineering

Industrial engineering

Manufacturing engineering

Mechanical engineering

Mining engineering

Nuclear engineering

Petroleum engineering

Sanitation engineering

Traffic engineering

CIVIL ENGINEERING:Civil Engineering is a broad field of engineering that deals with the planning, construction,

and maintenance of fixed structures, or public works, as they are related to earth, water, orcivilization and their processes. Most civil engineering today deals with roads, railways,structures, water supply, sewer, flood control and traffic. In essence, civil engineering may be

regarded as the profession that makes the world a more agreeable place to live in.

STRUCTURAL ENGINEERING:In the field of civil engineering, structural engineering is concerned with structural design

and structural analysis of structural components of buildings and non-building structures. Thisinvolves calculating the stresses and forces that affect or arise within a structure, and designingstructural components that are able to withstand those forces. Major design concerns are buildingseismic resistant structures and seismically retrofitting existing structures.


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Structural engineers ensure that their designs satisfy a given design intent predicated onsafety (i.e. structures do not collapse without due warning) and on serviceability (i.e. floorvibration and building sway are not uncomfortable to occupants). In addition, structural engineersare responsible for making efficient use of funds and materials to achieve these over-archinggoals. Typically, entry-level structural engineers may design simple beams, columns, and floorsof a new building, including calculating the loads on each member and the load capacity ofvarious building materials (steel, timber, masonry, concrete). An experienced engineer wouldtend to render more difficult structures, considering physics of moisture, heat and energy insidethe building components.

Structural loads on structures are generally classified as: live loads such as the weight ofoccupants and furniture in a building, the forces of wind or weights of water, the forces due toseismic activity such as an earthquake, dead loads including the weight of the structure itself andall major architectural components and live roof loads such as material and manpower loadingthe structure during construction. Structural engineers mainly fight against the forces of naturelike winds, earthquakes and Tsunamis. In recent years, however, reinforcing structures againstsabotage has taken on increased importance.

ENGINEERING DESIGN:

The task of the engineer is to identify, understand, and integrate the constraints on adesign in order to produce a successful result, which is called engineering design. It is usually notenough to build a technically successful product; it must also meet further requirements.Constraints may include available resources, physical or technical limitations, flexibility for futuremodifications and additions, and other factors, such as requirements for cost, and the ability tomarket, produce, and service. By understanding the constraints, engineers derive specificationsfor the limits within which a viable structure may be produced and operated.

Engineers typically attempt to predict how well their designs will perform to theirspecifications prior to full-scale production. They use, among other things: prototypes, scalemodels, simulations, destructive tests, nondestructive tests, and stress tests. Creating anappropriate mathematical model of a problem allows them to analyze it (sometimes definitively),and to test potential solutions. Usually multiple reasonable solutions exist, so engineers mustevaluate the different design choices on their merits and choose the solution that best meets their

requirements.Engineers as professionals take seriously their responsibility to produce designs that will

perform as expected and will not cause unintended harm to the public at large. Engineerstypically include a factor of safety in their designs to reduce the risk of unexpected failure.However, the greater the safety factor, the less efficient the design may be.

As with all modern scientific and technological endeavors, computers and software play anincreasingly important role. Numerical methods and simulations can help predict designperformance more accurately than previous approximations. Computer models of designs can bechecked for flaws without having to make expensive and time-consuming prototypes. Of late, theuse of finite element method analysis (FEM analysis or FEA) software to study stress,temperature, etc has gained importance. In addition, a variety of software is available to analyzedynamic systems.

EARTHQUAKE:Earthquakes are phenomena that result from the sudden release of stress in rocks that

radiate seismic waves. At the Earth's surface, earthquakes may manifest themselves by ashaking or displacement of the ground and sometimes tsunamis, which may lead to loss of lifeand destruction of property.

Most naturally occurring earthquakes are related to the tectonicnature of the Earth. Suchearthquakes are called tectonic earthquakes. The Earth's lithosphereis a patch-work of plates in


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slow but constant motion caused by the heat in the Earth's mantle and core. Plate boundariesglide past each other, creating frictional stress. When the frictional stress exceeds a critical value,called local strength, a sudden failure occurs. The boundary of tectonic plates along which failureoccurs is called the fault plane. When the failure at the fault plane results in a violentdisplacement of the Earth's crust, the elastic strain energy is released and elastic waves areradiated, thus causing an earthquake.

Figure 1: Earths lithosphere tectonic plates.

Figure 2: Earths lithosphere tectonic plates boundaries.

The majority of tectonic earthquakes originate at depths not exceeding a few tens of miles.Earthquakes occurring at boundaries of tectonic plates are called interplate earthquakes, whilethe less frequent events that occur in the interior of the lithospheric plates are called intraplateearthquakes.

Earthquakes occur on a daily basis around the world, most detected only by seismometersand causing no damage. Large earthquakes however can cause serious destruction and massive


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loss of life through a variety of agents of damage, including fault rupture, vibratory ground motion(shaking), inundation (tsunami or dam failure), various kinds of permanent ground failure(liquefaction, landslides), and fire or a release of hazardous materials.

Most large earthquakes are accompanied by other, smaller ones that can occur eitherbefore or after the main shock; these are called foreshocksand aftershocks, respectively. Whilealmost all earthquakes have aftershocks, foreshocks occur in only about 10% of events.

EARTHQUAKES AND BUILDINGS:In an earthquake, the building base experiences high-frequency movements, which results

in inertial forces on the building and its components. The force is created by the building'stendency to remain at rest, and in its original position, even though the ground beneath it ismoving. This is in accordance with an important physical law known as D'Alembert's Principle,which states that a mass acted upon by acceleration tends to oppose that acceleration in anopposite direction and proportionally to the magnitude of the acceleration (See Figure 1). Thisinertial force imposes strains upon the building's structural elements such as beams, columns,walls and floors. If these strains are large enough, the building's structural elements sufferdamage of various kinds, which may lead to the collapse of the building.

Figure 3: Acceleration, Inertial Forces.

To illustrate the process of inertia generated strains within a structure, we can consider thesimplest kind of structure imaginable--a simple, perfectly rigid block of stone (See Figure 2).

During an earthquake, if this block is simply sitting on the ground without any attachment to it, theblock will move freely in a direction opposite to that of the ground motion, and with a forceproportional to the mass and acceleration of the block. If the same block, however, is solidlyfounded in the ground and no longer able to move freely, it must in some way absorb the inertialforce internally. In Figure 2, this internal uptake of force is shown to result in cracking near thebase of the block.

Figure 4: Responses of a Simple Rigid Block.


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Of course, real buildings do not respond as simply as described above. There are anumber of important characteristics common to all buildings which further affect and complicate abuilding's response in terms of the accelerations it undergoes, and the deformations anddamages that it suffers.

The impact of an earthquake is determined by these factors:

Earthquake details - magnitude, type, location, or depth Geologic conditions - distance from the epicenter, path of the seismic waves, types

of soil, water saturation of soil

Social conditions - quality of construction, preparedness of the community, time ofday (e.g. rush hour)

Earthquakes can cause more damage and more deaths in some parts of the worldprimarily because

the buildings are poorly designed

the buildings are poorly constructed

seismic issues for the region have not been considered

population density.

When engineers design a building, they consider a variety of important factors:

Shape of the building: different shaped buildings behave differently. Geometricshapes such as a square or rectangle usually perform better than buildings in theshape of an L, T, U, H, +, O, or a combination of these.

Various materials used to construct the building(s) can be used (alone or incombination): steel, concrete, wood, brick. Concrete is the most widely usedconstruction material in the world. It is comprised of sand, gravel, and crushedstone, held together with cement. Each material behaves differently. Ductilematerials perform better than brittle ones. Examples of ductile materials includesteel and aluminum. Examples of brittle materials include brick, stone and

unstrengthened concrete. Height of the building. Different heights shake at different frequencies.

Soil beneath the building. Buildings constructed on soft soil force may suffer from astronger ground motion, and those on hard rocks are subject to high frequencywaves.

Regional topography. Buildings on a hill are likely to slide down as the earthquakestrikes.

Magnitude and duration of the earthquake.

Direction and frequency of shaking.

The number of earthquakes the building has previously had and the kinds of

damage suffered, if any. While the building may seem undamaged under weak tomoderate earthquakes, the resulting small damages and cracks make it morevulnerable to future events.

Intended function of the building (e.g. hospital, fire station, office building). If thebuilding is an important one, or the buildings performance is essential in case ofdestructive earthquakes, the engineers should design a stronger building which, onthe other hand, will be more expensive.

Proximity to other buildings.


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Financial limitations. Of course by spending a lot of money on a building, one canhave a very strong building, but it is the engineers task to make the most out of theleast resources.

Engineers standard approach to earthquake resistant design of buildings requiresproviding the building with strength, stiffness and inelastic (unrecoverable or permanent)deformation capacity, which are great enough to withstand a given level of earthquake-generated

force. This is generally accomplished by selecting an appropriate structural configuration andcarefully detailing the structural members, such as beams and columns, and the connectionsbetween them.

In more advanced engineering approaches the engineers not only strengthen the building,but try the amount of force transmitted to the main structural system. One of these methods isbase isolation, which directly reduces the effect of earthquake on the building. Another approachcan be putting advanced devices such as dampers in the building, which counter the effect ofearthquake, and reduce the amount of forces applied on the main structure.

Next, we briefly introduce some principles that should be considered in an earthquakeresistant building design.

LATERAL LOAD RESISTING SYSTEMSWhen designing a building that will be capable of withstanding an earthquake, engineers

can choose various structural components, the earthquake resistance of which is now well-understood, and then combine them into what is known as a complete lateral load resistingsystem. These structural components usually include:

diaphragms

shear walls

braced frames

moment resisting frames

base isolation

energy dissipation devicesThese same elements are also basic parts of an architect's structural "vocabulary." The

choice of the appropriate lateral load resisting system for any particular building is thus highlydependent upon the architectural concept of the building.

Of course, a building always possesses floors and a roof. But the earthquake resistantcharacteristics of these basic elements are highly variable. Not only that, the building's horizontalelements can be supported by a wide variety of wall and frame types or wall-frame combinations,the choice of which is usually dictated by considerations other than earthquake resistance. Forinstance, some buildings such as a warehouse or a parking garage must have a large open floorspace--which means that roof and floors of such structures will not be provided with as muchvertical support from beneath as they might be otherwise.

The engineer-designer in charge of making a building earthquake resistant must therefore

choose a combination of structural elements which will most favorably balance the demands ofearthquake resistance, building cost, building use, and architectural design.

DIAPHRAGMSDiaphragms are horizontal resistance elements, generally floors and roofs that transfer the

lateral forces between the vertical resistance elements (shear walls or frames). Basically, adiaphragm acts as a horizontal I-beam. That is, the diaphragm itself acts as the web of the beamand its edges act as flanges.


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Figure 5: Horizontal Diaphragm Action.

SHEAR WALLSShear walls are vertical walls that are designed to receive lateral forces from diaphragms

and transmit them to the ground. The forces in these walls are predominantly shear forces inwhich the fibers within the wall try to slide past one another.

When you build a house of cards, you design a shear wall structure, and you soon learnthat sufficient card "walls" must be placed at right angles to one another or the house willcollapse.

Figure 6: Shear Walls.

If you were to connect your walls together with tape, it is easy to see that the strength ofthis house of cards would immediately become greatly increased. This illustrates a very importantpoint: In general, the earthquake resistance of any building is highly dependent upon theconnections joining the building's larger structural members, such as walls, beams, columns andfloor-slabs.

Shear walls, in particular, must be strong in themselves and also strongly connected toeach other and to the horizontal diaphragms. In a simple building with shear walls at each end,ground motion enters the building and creates inertial forces that move the floor diaphragms. Thismovement is resisted by the shear walls and the forces are transmitted back down to thefoundation.

BRACED FRAMESBraced frames act in the same manner as shear walls, but they may offer lower resistance

depending on their details of their design and construction. Bracing generally takes the form ofsteel rolled sections, circular bar sections, or tubes. Vibration may cause the bracing to elongate


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or compress, in which case it will lose its effectiveness and permit large deformations or collapseof the vertical structure. Ductility therefore must be designed into the bracing to create a safeassembly.

MOMENT RESISTANT FRAMESWhen seismic resistance is provided by moment resistant frames, lateral forces are

resisted primarily by the joints between columns and beams. These joints become highly stressedand the details of their construction are very important. Moment frames use, as a last-resortresistance strategy, the energy absorption obtained by permanent deformation of the structureprior to ultimate failure. For this reason, moment resistant frames generally are steel structureswith bolts or welded joints in which the natural ductility of the material is of advantage. However,properly reinforced concrete frames that contain a large amount of steel reinforcing are alsoeffective as ductile frames. They will distort and retain resistance capacity prior to failure and willnot fail in a brittle manner.

Figure 7: Beam-Column Joint, Moment-Resisting Frame.

Architecturally, moment resistant frames offer a certain advantage over shear walls orbraced frames because they tend to provide structures that are much more unobstructedinternally than shear wall structures, which facilitates the design of accompanying architectural

elements such as exterior walls, partitions, and ceilings and the placement of building contentssuch as furniture and loose equipment. Nevertheless, moment resistant frames require specialconstruction and detailing and, therefore, are more expensive than shear walls or braced frames.

BASE ISOLATIONIt is easiest to see this principle at work by referring directly to the most widely used of

these advanced techniques, which is known as base isolation. A base isolated structure issupported by a series of bearing pads which are placed between the building and the building'sfoundation (See Figure 6). A variety of different types of base isolation bearing pads have nowbeen developed.


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Figure 8: Base-Isolated and Fixed-Base Buildings.

For our example, we'll discuss lead-rubber bearings. These are among the frequently-usedtypes of base isolation bearings (See Figure 7). A lead-rubber bearing is made from layers ofrubber sandwiched together with layers of steel. In the middle of the bearing is a solid lead "plug."On top and bottom, the bearing is fitted with steel plates which are used to attach the bearing to

the building and foundation. The bearing is very stiff and strong in the vertical direction, butflexible in the horizontal direction.

Figure 9: Lead-Rubber Bearing.

EARTHQUAKE GENERATED FORCESTo get a basic idea of how base isolation works, first examine Figure 8. This shows an

earthquake acting on both a base isolated building and a conventional, fixed-base, building. As aresult of an earthquake, the ground beneath each building begins to move. In Figure 8, it isshown moving to the left. Each building responds with movement which tends toward the right.We say that the building undergoes displacement toward the right. The building's displacement inthe direction opposite the ground motion is actually due to inertia. The inertial forces acting on abuilding are the most important of all those generated during an earthquake.


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Figure 10: Base-Isolated, Fixed-Base Buildings.

It is important to know that the inertial forces which the building undergoes are proportionalto the building's acceleration during ground motion. It is also important to realize that buildingsdon't actually shift in only one direction. Because of the complex nature of earthquake ground

motion, the building actually tends to vibrate back and forth in varying directions. So, Figure 8 isreally a kind of "snapshot" of the building at only one particular point of its earthquake response.

DEFORMATION AND DAMAGESIn addition to displacing toward the right, the un-isolated building is also shown to be

changing its shape-from a rectangle to a parallelogram. We say that the building is deforming.The primary cause of earthquake damage to buildings is the deformation which the buildingundergoes as a result of the inertial forces acting upon it.

The different types of damage which buildings can suffer are quite varied and depend upona large number of complicated factors. But to take one simple example, one can easily imaginewhat happens to two pieces of wood joined at a right angle by a few nails, when the very heavybuilding containing them suddenly starts to move very quickly--the nails pull out and the

connection fails.

RESPONSE OF BASE ISOLATED BUILDINGBy contrast, even though it too is displacing, the base-isolated building retains its original,

rectangular shape. It is the lead-rubber bearings supporting the building that are deformed. Thebase-isolated building itself escapes the deformation and damage--which implies that the inertialforces acting on the base-isolated building have been reduced. Experiments and observations ofbase-isolated buildings in earthquakes have shown that base isolation systems reduce buildingaccelerations to as little as 1/4 of the acceleration of comparable fixed-base buildings. As wenoted above, inertial forces increase, and decrease, proportionally as acceleration increases ordecreases.

Acceleration is decreased because the base isolation system lengthens a building's period

of vibration, the time it takes for the building to rock back and forth and then back again. And ingeneral, structures with longer periods of vibration tend to reduce acceleration, while those withshorter periods tend to increase or amplify acceleration.

Finally, since they are highly elastic, the rubber isolation bearings don't suffer any damage.But what about that lead plug in the middle of our example bearing? It experiences the samedeformation as the rubber. However, it also generates heat as it does so. In other words, the leadplug reduces, or dissipates, the energy of motion -i.e. kinetic energy - by converting that energyinto heat. And by reducing the energy entering the building, it helps to slow and eventually stopthe building's vibrations sooner than would otherwise be the case - in other words, it damps the


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building's vibrations. Damping is the fundamental property of all vibrating bodies which tends toabsorb the body's energy of motion, and thus reduce the amplitude of vibrations until the body'smotion eventually ceases.

ASECOND TYPE OF BASE ISOLATION:SPHERICAL SLIDING ISOLATION SYSTEMSAs we said earlier, lead-rubber bearings are just one of a number of different types of base

isolation bearings which have now been developed. Spherical Sliding Isolation Systems areanother type of base isolation. The building is supported by bearing pads that have a curvedsurface and low friction. During an earthquake, the building is free to slide on the bearings. Sincethe bearings have a curved surface, the building slides both horizontally and vertically (SeeFigure 9). The force needed to move the building upwards limits the horizontal or lateral forceswhich would otherwise cause building deformations. Also, by adjusting the radius of the bearing'scurved surface, this property can be used to design bearings that also lengthen the building'speriod of vibration.

Figure 11: Spherical Sliding Isolation Bearing.

ENERGY DISSIPATION DEVICESThe second of the major new techniques for improving the earthquake resistance of

buildings also relies upon damping and energy dissipation, but it greatly extends the damping andenergy dissipation provided by lead-rubber bearings.

As we've said, a certain amount of vibrational energy is transferred to the building byearthquake ground motion. Buildings themselves do possess an inherent ability to dissipate, ordamp, this energy. However, the capacity of buildings to dissipate energy before they begin tosuffer deformation and damage is quite limited. The building will dissipate energy either byundergoing large scale movement or sustaining increased internal strains in elements such as thebuilding's columns and beams. Both of these eventually result in varying degrees of damage.

So, by equipping a building with additional devices which have high damping capacity, wecan greatly decrease the seismic energy entering the building, and thus decrease buildingdamage.

Accordingly, a wide range of energy dissipation devices have been developed and are now

being installed in real buildings. Energy dissipation devices are also often called dampingdevices. The large number of damping devices that have been developed can be grouped intothree broad categories:

Friction Dampers: these utilize frictional forces to dissipate energy

Metallic Dampers: utilize the deformation of metal elements within the damper

Viscoelastic Dampers: are devices that show both stiffness and damping, andutilize the controlled shearing of solids


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Viscous Dampers: are devices that show only damping, and utilize the forcedmovement of fluids within the damper

FLUID VISCOUS DAMPERSTo try to illustrate some of the general principles of damping devices, we'll look more

closely at one particular type of damping device, the Fluid Viscous Damper, which is one variety

of viscous dampers that has been widely utilized and has proven to be very effective in a widerange of applications.

DAMPING DEVICES AND BRACING SYSTEMSDamping devices are usually installed as part of bracing systems. Figure 10 shows one

type of damper-brace arrangement, with one end attached to a column and one end attached to afloor beam. Primarily, this arrangement provides the column with additional support. Mostearthquake ground motion is in a horizontal direction; so, it is a building's columns which normallyundergo the most displacement relative to the motion of the ground. Figure 10 also shows thedamping device installed as part of the bracing system and gives some idea of its action.

Figure 12: Damping Device Installed with Brace.


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STRUCTURAL MODEL PROPERTIES:Understanding the requirements and limitations is one of the primary steps in engineering

design of a building. The engineer needs to know the level of performance required by thebuilding, the available material for construction, and of course, the overall cost that he/she isallowed to allocate for that building. Next, we list some basic properties of the materials and

components that are allowed to be used in the building.

FLOORS:2 Lauan Plywood 30 30 cm - The structure has 5 storiesmm cm

Mass: 275 (0.6 )g lb

Additional Mass: 490 g (1.08 lb )

COLUMNS:5 -Diameter Hardwood Dowels At least 4, up to 16 columns are allowedmm

Area: 17.81

2

mmArea Moment of Inertia: 25.25

4mm

Modulus of Elasticity: 34402

/N mm

CONNECTIONS:Wood Glue or Hot Melt Glue

ESTIMATED STRUCTURAL SYSTEM PROPERTIES:Damping Ratio: 16%

Natural Frequency: Ranges from 0.78 to 1.57 .s s

EXPLANATION OF PROPERTIES:Now, we briefly introduce the properties listed above, to point out their performance to the

engineer, who is responsible in the selection of appropriate components and configurations.

MASS:is a property of a physical object that quantifies the amount of matter and energy itcontains. Unlike weight, the mass of something stays the same regardless of location. During anearthquake, the ground acceleration results in inertial forces to be produced in masses present inthe structure. The more the mass, the more the force will be, and hence, stronger elements arerequired to handle it during an earthquake.

AREA:is a physical quantity expressing the size of a part of a surface. Larger areas of thesame material normally produce more resistance to loads, but the shape of the part is also

important in determination of its stiffness.

AREA MOMENT OF INERTIA: is a property of a shape that is used to predict itsresistance to bending and deflection. Shapes of the same areas and materials may have differentmoments of inertia, implying different resistance to external forces.

MODULUS OF ELASTICITY: is the mathematical description of an object or substance'stendency to be deformed when a force is applied to it. Theoretically, it can be defined as theamount of force required to reduce the length of an object with unit area and length to zero. Asthis definition suggests, stiffer materials exhibit higher values elasticity modulus.
http://c/wiki/Forcehttp://c/wiki/Force


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DAMPING: is any effect that tends to reduce the amplitude of oscillations of an oscillatorysystem. All structures demonstrate damping in a variety of ways, as no oscillation will last foreverin any system. Damping ratio is a numerical quantity showing the damping as a percentage of acritical damping, which is enough to prevent any oscillation in the system. Real values of dampingin civil engineering structures range from 2% to 10% of the critical value, depending on thematerial and geometric properties, as well as excitation severity. Supplemental damping for

reduction of oscillation is possible through installation of special devices called dampers in thebuilding.

NATURAL FREQUENCY: is the oscillation rate at which the structure tends to oscillate.This property depends on the material and geometric properties of the elements, as well as theoverall configuration of structure, connection properties, and the amount of mass present in thebuilding. A specific structure demonstrates several natural frequencies and their correspondingmode shapes (oscillation form). When the natural frequency of the excitation gets closer to thenatural frequency of the building, resonance occurs, which results in increased drifts andaccelerations of the structure.

EARTHQUAKE RECORDS:The earthquakes that are selected to be applied to the building are the 1940 El Centro,

1994 Northridge, and 1995 Kobe records. These data are actually recorded during the above-mentioned earthquakes. The first one happened in Imperial Valley, CA, and was one of the firstearthquakes to be accurately recorded by the pre-installed instruments. The other two arestronger than El Centro, but they happen less frequently. Each earthquake has specific propertiesthat make it different from others, and may affect the building in a very different way.

The problem is now to design a building, using the material whose properties werementioned above, to suffer the least damage under these earthquakes. As the El Centro record isweaker than the others and its probability of occurrence is more, the building should be designedto remain undamaged. The other two earthquakes, however, are too strong for a building toremain undamaged, as it is too expensive to design a building that survives any earthquake. Sostandards generally require the buildings to be designed in such a way that they dont collapseunder strong earthquakes, but they may have some damage at the end. This shows theimportance of the inelastic deformation capacity of a building that allows it to deform, but notcollapse.

TESTING BUILDINGS:A variety of experimental methods exist for testing buildings or building components under

the effect of earthquakes. These methods range from application of forces by actuators to large-scale shake table tests.

In a shake table test, a reduced-scale model of building will be placed on a platform thatcan simulate a pre-recorded earthquake by moving in horizontal and vertical directions. Simplifiedversions of these shake tables are able to move in one direction only, and have limited force anddisplacement capacity. As Figure 11 shows, there are some additional masses attached to eachfloor, to represent the effect of entities present in any building, such as walls, appliances and

furniture. The deformations and accelerations of test structures are measured by the instrumentsthat are mounted on the system. These measurements give valuable information to the engineer,that helps predict the structural behavior under a real earthquake.


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Figure 13: An instrumented building model on a shake table.

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