assessment of the damage of the 25 january 1999 earthquake armenia and pereira, colombia

7/28/2019 Assessment of the Damage of the 25 January 1999 Earthquake Armenia and Pereira, Colombia

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RIED final April 2000 102-Mar-06

Rapid Inventory of EarthquakeDamage (RIED)

Rapid Inventory of Earthquake

Damage (RIED)

Assessment of the damage of

the 25 January 1999 Earthquake

inArmenia and Pereira, Colombia


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ObjectivesObjectives Rapid assessment of the damage inflicted by

the earthquake

To make recommendations for the

reconstruction of the buildings and structuresin the damaged areas


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MeansMeans High resolution aerial photographs

Integration of existing and new data in aninformation technology environment to allowfast analyses and visualization forreconstruction


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Organizations InvolvedOrganizations Involved Ministry of Foreign Affairs, Netherlands

Ministerio del Medio Ambiente, Colombia



Organisations Involved (cont.)Organisations Involved (cont.) Coorporacion Autonoma Regional de Risaralda

(CARDER) Corporacion Regional del Quindio (CRQ)

Fondo para la Reconstruccion y Desarollo Social del

Eje Cafetero (Reconstruction Fund), Armenia Instituto Geografico Agustin Codazzi (IGAC)

Ingeominas

Int. Inst. For Aerospace Survey and Earth Sciences(ITC)

Delft University of Technology (TU Delft)



Earthquake damage inventory by

aerial photographs

Earthquake damage inventory by

aerial photographs Structures on aerial photographs were marked in 4

classesTotal Collapse

Roof Collapse

Roof Partly Damaged No Damage Visible but Rubble in the Street

No Damage Visible


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Comparison Aerial Survey Ground

Survey

Comparison Aerial Survey Ground

SurveyReasonable correlation for the highly

damaged structures such as structuresthat completely collapsed or for

structures of which roof and partially thewalls collapsed.

Less correlation for structures with lesssevere damage. (This is understandable because cracks infacades and sidewalls of structures are not observed in aerial photographsbecause of the angle of observation and the resolution of the photographs.)


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Results Aerial Photographs Damage

Inventory


InventoryFor reconstruction purposes the

inventory gives a good impression ofthe damage and of major geological,geotechnical, and morphologicalfeatures that have influenced thedamage inflicted on surface structures

The presence of such features canthen be considered in the planning forreconstruction.


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Inventory (Cont.)


Inventory (Cont.)The results of an inventory of damage

by aerial photographs can be availablemore rapidly after an earthquake, as

compared to a ground survey. This is ofgreat benefit for relief operations and forreconstruction planning.


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1D Ground response analysis1D Ground response analysisTest case Brasilia site


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Accelerogram CCALA EW

-600

-400

-2000

200

400

600

0 5 10 15 20 25 30 35 40

Time (sec)

Acceleratio

n(cm/sec

2)

Base level (input) signal


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CCALA EW - Profi le N. Brasil ia - Layer No. 1 (Surface)

Acceleration(g)

Time (sec)

-0.2

-0.4

-0.6

-0.8

-1.0

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Surface (output) signal


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N. Brasilia - Layer 1 - CCALA EW

Layer No. 1

FourierAmplitudeSpectrum

Frequency(Hz)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0 2 4 6 8

ON Soil pro file - Analysis No. 1 - Profile No. 1

Layer No. 4

FourierAmplitudeSpectrum

Frequency(Hz)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0 2 4 6 8

Frequencyanalysis(Fourier

analyses)

Base level

(input) signal

Surface(output) signal


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CCALA EW - Profile N. Brasilia

Sa for 5%damping

Spec

tralAcceleration(g)

Period (sec)

0

1

2

3

4

5

6

0.01 100.1 1

Response spectrum (at surface)


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Microzonation of ArmeniaMicrozonation of ArmeniaMicrozonation of Armenia

Microzonation based on geotechnicalmodel of sub-surface

Coupling between GIS and Shake Automatic response calculation for

each grid cell Dimensions grid cells 15 x 15 m


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Profile 1154355

1400

1410

1420

1430

1440

1450

1460

1470

991800 991900 992000 992100 992200 992300 992400

Distance (m)

Elevation(m.asl)

Ash

Residual soil

Saprolite

Lahar/pf

Ash

Residualsoil

Saprolite

Lahar/pf

N. Brasilia

S N


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T di i l T hiT di i l T hi


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Two-dimensional Topographic

Effects

Two-dimensional Topographic

EffectsQualitative calculation topographic

effects

Correlated with damage pattern


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Three-dimensional EffectsThree-dimensional EffectsThree-dimensional modeling of

topographic effects Brasilia area

Surface accelerations are up to 2 to 4

times the base level (input)accelerations


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Surface acceleration as result of3D modeling: red is high; blue islow acceleration

S f l ti lt f


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Surface acceleration as result of3D modeling: maximum

acceleration 3 m/s2 which isabout 3 to 4 times the maximumin the base level signal


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LimitationsLimitationsFew data on sub-surface available

Simplified model

Only for the characteristics of the 25

J anuary 1999 earthquake


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Information TechnologyInformation TechnologyThe development of an information

technology environment for Pereira andArmenia will allow fast analyses,

visualization, and production of damageinventory, for recommendations forreconstruction after future earthquakes


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Structural ObservationsStructural Observations Visual structural analyses:

Flat slabs on columnsTorsional buildings

Lateral reinforcement in columns Short-columns

Masonry in-fills

Soft-stories

Concrete quality

Flat Slabs andFlat Slabs and


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Flat Slabs and

Columns

Flat Slabs and

ColumnsThis structural system has

been known to be a non-ductile system since theonly available energy-dissipating members arethe columns.

Solution is weak-beams-

strong-columnsmethodology, usuallyknown as capacitydesign.

T i l R iT i l R i


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Torsional ResistanceTorsional Resistance

The severe column damages in the columnsat the periphery of the building is a strongindication of lack of torsional resistance.

ShearShear


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Shear

Reinforcementand Lateral Ties

Shear

Reinforcementand Lateral TiesColumns had failed in shear

at the points of maximumbending moment due to notadequately anchored shear

reinforcement. Frequently,buckling of the mainreinforcing bars was also

evident. Lateral ties werenot adequate in providinglateral support to the mainbars causing the concrete to

be crushed to rubble


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Short-columnsShort-columnsSome typical cases of short-

column behaviour wereobserved. In all of these thereason was the interaction of

the column with adjacent(non-structural) elements.

MasonryMasonry


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Masonry

In-fill

Masonry

In-fill

Workmanship problems were observed in the majority of

damaged masonry in-fills. As a result, collapse of the in-fill prevented failure of the adjacent columns. In all casesit was observed that the in-fill was constructed totally

against the column.

EmbeddedEmbedded


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Embedded

Utilities

Embedded

Utilities

Utility items embedded in the body of the masonry wall.

These can create planes of weakness in the body of the wallwhich can then fail by slippage. In one case, slippage failureof the wall had clearly resulted to shear failure of the

adjacent column.


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Soft-storiesSoft-stories

Soft-storeys. The reduction of the stiffness at a certain level

of the building, typically at one of the bottom floors, results insevere damage in the top and bottom of vertical structural

elements due to lack of lateral reinforcement.

ConcreteConcrete


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Concrete

Quality

Concrete

Quality

In some cases, high sand percentages were observed.

Also, the gradation characteristics of the concrete mixesseem to be not complete. Both of these can lead to concrete

of inferior strength and reduced ductility.


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ConclusionsConclusionsRapid inventory by aerial photographs

gives fast and decent input forreconstruction planning

Information technology environmentgives possibilities for rapid analyses,visualization and production of maps

Measures (often simple and cheapmeasures) in structural engineering willavoid large damage in future


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RecommendationsRecommendationsSeismology investigation to determine

frequency of occurrence andcharacteristics of future earthquakes

Public awareness campaign

assessment of the damage of the 25 january 1999 earthquake armenia and pereira, colombia

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