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Case study on directing plastic

hinges from columns into beams

Scientific Team:

asist.dr.ing. Ioana Olteanu

prof.dr.ing. Alex Barbat (from UPC, Barcelona, Spain)

ing. Radu Canarache

Iasi, Mai 2013


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CONTENT:

Natural disasters

Vulnerability

Seismic risk assessment

Case studies


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earthquakes 9%

meteorological events 69%

landslides

5%

drought

8%

extreme temperature

3%

31%

floods

pests

1%

volcanoes

2% fires

3%

storms

27%

epidemis

11%

9%

earthquake and tsunami

Natural disasters


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The risk

The disasters

are not natural

is not natural either

hazard vulnerability

is not naturalis natural


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VULNERABILITY

Vulnerability is a set of prevailing or consequential conditions, which adversely

affect an individual, a household or a community's ability to mitigate, prepare for or

respond to the earthquake hazard.

Vulnerability factors:Population

density

Physical

assets

Economic

activity

Anderson and Woodrow (1989) grouped vulnerabilities into three categories:

Physical/material vulnerability: inherent weakness of the built environment and

lack of access to resources, especially of poor section of the population

Social/organizational vulnerability: inherent weakness in the coping mechanism,

lack of resiliency, lack of commitment

Attitudinal/motivational vulnerability: fatalism, ignorance, and low level of

awareness


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focus

Seismic vulnerability, V: elementpredisposition to suffer a specificloss as a result of a seismic action ofa specific intensity S.

Seismic hazard, H: probability of occurrence

of a seismic event with a severity greater than

S during a exposure period T.

Seismic risk index


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VULNERABILITY vulnerable elements in the physical environment

older residential and commercial buildings and infrastructure constructed of

unreinforced masonry (i.e., URM's) or construction materials with inadequate

resistance to lateral forces;

older non-engineered residential and commercial buildings that have no lateral

resistance and are vulnerable to fire following an earthquake;

new buildings and infrastructure that have not been sited, designed, and

constructed with adequate enforcement;

buildings and lifeline systems sited in close proximity to an active fault system, oron poor soils that either enhance ground shaking or fail through permanent

displacements (e.g., liquefaction and landslides), or in low-lying or coastal areas

subject to either seiches or tsunami flood waves.

schools and other buildings that have been built to low construction standards.

communication and control centers that are concentrated in one area. hospital facilities that is insufficient for large number of casualties and injuries.

bridges, overhead crossings and viaducts that are likely to collapse or be

rendered unusable by ground shaking.

electrical, gas, and water supply lines that are likely to be knocked out of service

by ground failure


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Vulnerability factors

Short column

Diagonal crack and shear collapse of the column due to this phenomenon almost lead to thegeneral collapse of a parking structure (Northridge, California, 1994)


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Reinforced concrete frame infill

(a) (b)(a) Masonry infill cracking (Izmit, Turcia, 1999) (b) The stiff masonry lead to the shear of the

columns (Adana - Ceyhan, Turcia, 1998)Examples of collapsed columns due to the forming of short column because of discontinuities in

the infill masonry (Izmit, Turcia, 1999)


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Insufficient stiffness due to plates

Structures made of prefabricated elements with inadequate connections (Armenia, 1988)


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SEISMIC RISK ASSESSMENT

F

F

Capacity spectrum method, ATC-40

Capacity curve

F

b

a

1

VS

W

top

d

1 top

SPF

Sa

Sd


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Design spectrum

-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00

Earthquake recording from March 1977, PGA=0.20g

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50

Sa(0.2g)

T(s)

Design spectrum, Sa-T

2

d a2

TS = S

4

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Sd(cm)

Design spectrum, AD format



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Deplasare spectralaSd

P

SaP

Spectru de proiectare cuamortizare de 5%


Performance point



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Biliniar idealization of the capacity curve

Dy Du

Ay

Au



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Dy Du

Ay

Au

Sd3 Sd4Sd1 Sd2

Complet4

Sever3Moderat2

Usor degradate1

Fara degradari0

ds descriere

0

12

3 4 Sd,1 = 0.7 DySd,2 = DySd,3 = Dy+0.25(Du-Dy)Sd,4 = Du


Damage states limits



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RISCUL SEISMIC

SdP0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Slab

Fara degradati

Moderat

Sever

Complet

Sd (cm)

P(

DS>dsi/

Sd=Sdi)

Metoda spectrului de capacitate, ATC-40Determinarea curbelor de fragilitate


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3D FRAME STRUCTURE


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3D FRAME STRUCTURE


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3D FRAME STRUCTURE

(a) (b)

Frame type C2: (a) Crack development in the concrete; (b) Reinforcement stresses for a loading

of 1000 kN


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3D FRAME STRUCTURE

(a) (b)


of 800 kN


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3D FRAME STRUCTURE

(a) (b)


of 800 kN


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3D FRAME STRUCTURE

(a) (b)


of 800 kN


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3D FRAME STRUCTURE

(a) (b)


of 1000 kN


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3D FRAME STRUCTURE

(a) (b)

Plastic hinge development: a model C2; b model C6.


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3D FRAME STRUCTURE

Cracks and stress development for : a model C1;

b

model C2; c

model C4; d

model C6.


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0

200

400

600

800

1,000

1,200

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18

Fortataietoaredebaza(KN)

Deplasare (m)

Cadru fara placa

Placa plina 15 cm

0

200

400

600

800

1000

1200

0.00 0.01 0.02 0.03 0.04 0.05 0.06

Fortataietoarel

abaza(KN)

Deplasare (m)

Cadru cu placa plina de 15 cm - armare normala

Cadru cu gol la placa 50cm pe colt armare redusa

Cadru cu inlocuire material pe colturi 50 cm armareredusa

Cadru cu rost 5mm la placa pe colt - armare completa

3D FRAME STRUCTURE


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EFFECT OF INFILL MASONRY

Capacity curves for a 3 level 2D reinforced concrete frame structure with different infillgeometries


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EFFECT OF INFILL MASONRY

Plastic hinge development, frame with 4th infill model: (a) without joint, (b) with 5

cm joint


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Case study on directing plastic

hinges from columns into beams

Scientific Team:

asist.dr.ing. Ioana Olteanu

prof.dr.ing. Alex Barbat (from UPC, Barcelona, Spain)

ing. Radu Canarache

Iasi Mai 2013

vulnerabilitate bucuresti mai2013

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