Reinforced Concrete Structures: Failures, Causes, and

11-04-2013
REINFORCED CONCRETE STRUCTURES
FAILURES
CAUSES AND RESPONSABILITIES
CONTENTS
Lights & Shadows
Technical Causes
Carlos Videla C.
The Human Factor
ESCUELA DE INGENIERÍA
PONTIFICIA UNIVERSIDAD CATÓLICA DE CHILE
Responsibilities for Construction Faults
Conclusions
Carlos Videla © 2010
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R.C. Lights
REINFORCED CONCRETE:
LIGHTS & SHADOWS
Panteón de Agripa, Roma, 120 DC /
Arq. Apolodoro de Damasco
Marriot,
145 m
1999
Metro
Línea 4,
2004
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Federico Assler,
Premio Nacional de Arte Carlos
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Challengues of R.C. Construction
Height: Kingdom Tower, Arabia Saudita
Costanera Center
Tall Buildings
Height: 300 metros
Stories: 60
fc’ = 70 MPa
Titanium La Portada
20xx -??
Height: 192 metros Stories: 52
160 pisos
705 m.
fc’ = 60 MPa
2007-2010
Marriot,
145 m, 1999
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Shapes: Spiral Tower – Songdo, Korea
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New Technologies
Concrete Pumping Test over
600 m,
Dubai (Feb. 2005)
David Scott,
ARUP
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SCC
175 m, 52 stories, giro 110°
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Dificulties of Design
Ronald Klemencic,
Magnusson Klemencic
Associates
Wind Tunnel
Costanera Center
SHADOWS OF
CONCRETE
CONSTRUCTION
The dark side
of the force
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Pittsburg garage parking
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Even the collapse of the building can be
produced
Collapse of the works even without loads
The document detected
three types of deficiencies
in the structure: bonding
in the horizontal
concrete construction
joints,...…
Alto Río Building
27 de Marzo de 2010
Concepción, CHILE
13 stories building under construction tilt in Shangai
29 of June, 2009
http://cache.daqi.com/view/2617990.html
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and Reduce the Service Life of the Structures
TECHNICAL
CAUSES
February 27th, 2010 – Chile
CHILEAN EQ. CASE
Degradación del hormigón producto de la corrosión de las
armaduras de la losa
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Disclaimer
This presentation uses a large number of pictures and
evidence that professor Videla has gathered as an
evidence of the Earthquake and Tsunami in Chile.
Most photographs where taken personally or by members
of his company however, others have been obtained from
internet and other sources and makes it very difficult to
independently acknowledge some of the sources.
SOME FIGURES ABOUT THE 27F
CHILEAN EARTHQUAKE
However special thanks are given to:
• Augusto Holmberg, CEO, ICH
• René Lagos, renelagos engineers
• Rodrigo Mujica, VMB Ingeniería Estructural
• Carl Luders, SIRVE S.A.
• Patricio Bonelli, Universidad Santa María
• Leonardo Massone, University of Chile
• René Guerra y Daniel Díaz, Videla y Asociados
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Accelerations …
Some Figures about the 27F EQ
•
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Chile 2010 EQ Mw = 8.8
Epicenter close to Concepción
Depth: 35 Km
Subduction zone - Length of
rupture 500km (approx.)
• RC building damage
• Affected cities - Concepción, Viña
del Mar, Santiago, among others
Informe preliminar Nº 3 - 15 de Marzo de 2010
Red Nacional de Acelerógrafos
Boroschek R, P. Soto, R. Leon,, D. Comte
www.renadic.cl
Maipú, Renadic – 10/05 report
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The Very Bad Earthquake Effects...
• Dead or missed people: less than 500
(mainly by tsunami)
THE GOOD AND THE BAD
OF THE 27F EARTHQUAKE
• Houses damaged:
300,000 to 500,000
(mainly adobe)
• Reconstruction:
30 US billions (15% GDP)
ICH Non oficial figures
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• Water run-up
• Maremoto = Tsunami
Courtesy Univesidad
Catolica
Recognition group
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Historical Buildings
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Museo Nacional
de Bellas Artes
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• Curico Church
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Adobe construction
Typical Chilean
Farm House
Adobe Construction
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Adobe construction
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Adobe construction
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• “Modern” adobe construction
RC Buildings - Good & Bad
How did buildings performed?
Considering only buildings between 1985 to 2009 (CChC)
• Buildings that collapsed:
• Buildings to be demolished:
4
25 - 50 (estimate)
• Buildings heavily damaged: 50 – 100 (< 1% stock
of bulidings)
• Non structural components: extensive damage
V&A
• Number of buildings 3 + story
9.974
• Number of buildings 9 + story
1.939
• Failures 3 + story buildings: 0.5%
• Failures 9 + story buildings: 2.8%
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Titanium Tower – Santiago, Chile
52 storIes
192 meters high
EXAMPLES OF BUILDINGS
WITHOUT STRUCTURAL DAMAGE
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Titanium Tower
Telefónica Building – Santiago, Chile
• Construction Area:
•
•
•
•
65.000 m2 total
35.000 m2 main tower
Tower typical floor: 20m. x 47m.
Building height 140 meters
Stories
33 + 3
Year of Completion: 1996
Energy dissipation
devises
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Isidora 3000
Isidora 3000 – Chile (2008)
Mix use
Structure Singularities:
Column Deviations
3rd floor
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2nd floor
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Justice Buiding
Santiago Chile. (2003)
Office buildings (2008)
Isidora Foster + Magdalena – Chile
• 25 stories
• 9 basement
• 72.000 m2
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Concepción
EXAMPLES OF BUILDING
FAILURES
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Edificio Salas 1343 Torre A - Concepción
Edificio San Pedro Concepción
Edificio Centro Mayor - Concepción
Edificio Obispo Salas - Concepción
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Edificio Alto Río
Edificio Alto Río
Edificio Alto Río - Concepción
Concepción
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Edificio O´Higgins 241
Viña del Mar
Edificio Toledo – Viña del Mar
Edificio Tricahue – Viña del Mar
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Edificio Tenerife – Viña del Mar
Santiago
Emerald - Santiago
Condominio los Robles - Huechuraba
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Central Park - Santiago
Edificio DonTristán - Maipu
Walls
Design Failures
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• T & rectangular walls with
flexural-compression damage at
1st floor or basement
• T walls with damage at web
• No SBE – concrete crushing and
rebar buckling
• Splice failure
Flexural-compression brittle failures
Concrete crushing and rebar buckling
Overall buckling of thin walls
Splice failure
Soft floor (irregularities)
Rebar Fracture
Lack of concrete confinement
Deficient reinforcement detailing
Few shear failures
Walls too slender (thickness 20 cm)
Very heavy loaded walls
P. Bonelli
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Splice
failure
J. Wallace
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Diagrama de Piso Blando
Soft floor
Walls
• No SBE – concrete crushing
and rebar buckling & fracture
• Overall buckling – thin walls
J. Wallace
Muro discontinuo de zócalo
(Edificio Hipódromo Chile)
J. Wallace
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Lack of concrete confinement
Compression failure and buckling of
vertical bars
Armaduras abiertas en muro discontinuo
(Edificio Sol Oriente)
Edificio El Parque
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Diagrama Armadura Transversal
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Detailing of reinforcement
Detailing of reinforcement
Reinforcement bent at 90°
(Edificio Emerald)
Falta de retorno de la malla horizontal (Edificio El Parque)
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Detailing of reinforcement - splice
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Flexural-compression failure
Anclaje vertical de
armaduras
horizontales
(Edificio El Parque)
Edificio Los Cerezos
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Edificio Emerald
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Few shear failures
Walls too slender (thickness 20 cm)
Edificio El Parque (fisura corte 0,5 mm)
Edificio Toledo, Viña
Edificio Alto Río, Concepción
Edificio Central Park
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Very heavy loaded walls
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Car Park
Edificio El Parque
Edificio Central Park
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Torre Bilbao, Santiago
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After the 2010 Chilean Earthquake
some things have to be revised:
• After the 1985 Chilean Earthquake it was
thought:
Concrete Design Code
• Limit slenderness of the shear walls
• Limit the compression in shear walls
• Confinement of boundary elements
• Confinement at longitudinal splices
The typical structural wall in a Chilean building
need not have boundary elements or special
transverse reinforcement.
The good performance of the majority of these
buildings during the March 3, 1985 earthquake
suggests that bearing walls with limited
detailing may be an effective construction form
for earthquake resistance
Earthquake Loading
• Revise the design spectrum
• Revise the soil amplification effects
• Define displacements and rotational demands
Construction Failures
Reinforcement detailing
De most frequent encountered problems
were:
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• Reinforcement detailing (Missing
confinement reinforcement)
Bad construction joints
Lack of concrete continuity
•
•
• Excess reinforcement cover, reducing
the lever arm
• Movement joints
• Low strength concrete
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Confinement
Location
Righteousness
Cleaning
Stirrups
Ties
Splices
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Reinforcement detailing: confinement
Reinforcement detailing
• Horizontal mesh reinforcement not closed
• Missing confinement reinforcement
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Reinforcement detailing
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Reinforcement detailing: stirrups
I never thought that this could really happen.
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If we where following
ISO why we did not get
the right spacing.
In this case at least they
should have place the
steel.
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Reinforcement detailing: detailing
Reinforcement detailing: location
Eccentric
reinforced
bars
• Different to drawings
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Bad construction joints
Reinforcement detailing: location
• No cover
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Lack of concrete continuity
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Movement joints
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Excess reinforcement cover
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Low strength concrete (poor)
(furtive – covert)
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Failure of Non Structural Members
• Partition walls
• Ceilings
• Glasses
FAILURES OF NON STRUCTURAL
MEMBERS
• Equipment
• Feetings
• Finishing
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Ceilings
Partition walls
Gypsum
Pudahuel Airport
Tabiques de yeso
(Edificio en Santiago, Ñuñoa)
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The Chilean International
Airport was out of service
at the most critical time for
Chile.
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Glasses
Glasses
Glass Doors
Windows
3m
Concepción Airport
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Equipment
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Fittings
Machine room and heaters equipment
(Ciudad Empresarial Building, Santiago)
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Daños en sistema de aire acondicionado y protección
contra el fuego (Santiago y Concepción)
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Furniture
Finishing
• Veneer  90% OK
DUOC; San Carlos de Apoquindo
V&A
Daños del contenido (Edificio Stgo., Ciudad Empresarial)
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Finishing •
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Finishing
Stucco
• Architectural Details
V&A
Universidad del Desarrollo
Excessive thickness of stucco to
rectify plumbs
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Finishing
Secondary Structures
• Curtain Walls
OK
Pudahuel Airport
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Mall Portal La Dehesa
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Schools
V&A
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Causes of the Pathologies of
RC Structures
THE HUMAN FACTOR
Ignorance
or
Irresponsability?
Incapacity
or
Indifference?
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Inexperience
or
Negligence?
Incompetency
or
lack of
foresight?
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The human factor
García Messeguer A.
CAUSES:  Ignorance
 Carelessness
 Negligence
 Excess of confidence
 Apathy
 Lust
LET SEE THE
KNOWLEDGE
The Pareto variable of construction quality, whose
improvement has the largest impact on the
improvement of the total, been equal the rest of the
factors is
THE HUMAN FACTOR
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From an Ancient English Proverb
Books
...... (Structural) Engineering is the art of moulding
materials we do not wholly understand into shapes we
cannot precisely analyse, so as to withstand forces we
cannot assess, in such a way that the community has no
reason to suspect our ignorance........
Ironbridge,
Cast-iron arch bridge-1779,
River Severn,
Coalbrookdale, Shropshire,
England
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A. Neville (1981)
If the reader is unable to design
a satisfactory mix he should
seriouly consider the alternative
of construction in steel
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IF WE KNOW SO MUCH,
WHY THE FOLLOWING
FAILURES OCCUR?
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Postensioning of Flat Slabs
Unshoring of slabs
(Quito, Octubre 2002)
V&A
V&A
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Slab camber and make
perpendicular walls during
construction
COULD BE THAT WE ARE NOT
DOING AND APLYING SOUND
ENGINEERING PRINCIPLES?
V&A
V&A
Slab
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Wall
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Sophisticated modeling programs tools for
structural design, but…
Divorce between Structural Engineering and
Construction Engineering
Possible weakness: Uncertainty on structural
modeling
• Modeling of foundations:
–
–
–
Vertical rigidity of the soil
Empotramiento at the base versus
foundation rotation
Lateral confinement of the
underground
Excessive cracking due to
construction sequence
• Modeling of structural elements:
–
–
–
–
Structural Engineers
do not consider the
construction process
in the design stage
Use of finite elements versus uniaxial elements
Rigid or flexible diaphragms
Geometrical properties with or without cracking
Etc.
renelagos
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engineers
Magellines Pier, V&A 2012
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Forensic Engineering (post construction
structural evaluation)
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Construction Engineers used to
point out that structural engineers
were standing far from the actual
constructions sites. This still
remains true but, …
Magellines Pier, V&A 2012
G. Thenoux
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Divorce between Structural Engineers and
Reality
Massive R.C. Mat Foundations,
Costanera Center Building, 2010
SCC – 50 MPa
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Designing something difficult to built
(common sense)
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Divorce between Construction Engineering
and Construction Management
Sup. 16@20 + E 12@40
Since construction
management arrived in
our field we have been
talking to different
language.
Inf. 18@
Sup. 25@10 + Suple 28@10
Inf. 25@10 + Suple 28@10
G. Thenoux
R.C. Slab
V&A, 2008
Moving reinforcing
bars with a bar to
vibrate concrete
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Divorce between Construction Engineering
and Construction Management
Since construction management arrived in our
field we have been talking to different language.
Carlos Videla © 2010
Many construction engineers are also looking the
construction site through the computer screen. This
is ok since they make take advantage of many new
application tools for planning, programming and
building however…..
Carlos Videla © 2010
Some phrases about Constructors
• Drawings must be very detailed to avoid
constructors to think o interpret
(design office).
• Information for in situ engineers must be very
concise and simple and a maximum of 2 pages
extension because they don’t read.
(visiting engineer of a construction company).
• Constructors don´t have the capacity nor the
knowledge allowing them to place in doubt
structural design drawings
(owner of a construction company).
Drawings are a window
through which the knowledge
is seen (or measured)
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• In situ professionals don´t like to write to register
anything (all the previous).
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Construction Engineering =
Rule of Thumb?
More phrases
• Constructors are only worried about administrative
duties like acquisitions, quotations, budgets,
programming; they don´t care about the execution
of the work in-situ and rely on the work of the
technical labor
(me).
Casting mas
concrete
• The main work of the ITO is adminsitration of
the contract: approve payment, check
productivity, evaluate time, etc.; they don´t
verify the quality of the construction
(structural engineers).
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Mass Concrete Case
HOW GOOD ARE WE DOING WITH
QC/QA IN BUILDING
CONSTRUCTION?
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LUST
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Concrete- testing company says NYC results
Concrete SmartBrief aci@smartbrief.com
were not faked
August 5, 2011
American Standard Testing and Consulting Laboratories denies allegations
that it falsified thousands of test results on several New York City projects,
including a La Guardia Airport control tower and the new Yankee Stadium.
Company President Alan Fortich and five staff members Thursday pleaded
not guilty to racketeering and other charges. The company's defense
attorney, Richard Leff, said the concrete strength tests were done correctly.
RESPONSIBILITIES
FOR CONSTRUCTION
DEFECTS
• The New York Times
• The Associated Press
The six defendants accused of
falsifying concrete tests in State
Supreme Court on Thursday.
By William K. Rashbaum
Published: August 4, 2011
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DEVELOPERS = RESPONSIBLE (Guilty) 142
HOW DEVELOPERS WERE SEEN Article 18: The first vendor owner of a construction will be responsible for all the damages and financial losses due to faults or defects on it, whether…..
ENASEI 2010 ‐ Institutode la Construcción
ENASEI 2010 ‐ Institutode la Construcción
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Construction Process and Responsibilities
SCIENTISTS STAGE
Design
L'Aquila EQ
COMPETENCE
Architect
Construction
Engineer
Fabrication
 Selección de
materiales más
adecuados y
económicos.
 Fabricación
 Transporte
Construction
The Globe and
Mail
October 23, 2012
Structural
Engineer
In situ
Supervisor
145
Resistencia
prevista en
función de los
Materiales y
Diseño Proceso
Constructivo
Structure
Potential
Quality
Labour
Inspection
Structure
Actual Quality
Finished
Project
Carlos Videla © 2012
Structure Specified
Quality
Labour
QA&QC
in-situ
 Colocación
 Armaduras
 Moldajes
 Hormigón
 Compactación
 Curado
RESULT
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Would you buy this
Lamborghini
Murciélago?
HIDDEN CONSTRUCTION
DEFECTS
And now?
¿ ?
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El Mercurio, 3 de Septiembre 2010
HIDDEN CONSTRUCTION
DEFECTS
It affects the
public faith
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What can we expect of these
cases?
Ethic?
“I put less cement on the
foundations, but nobody
will never notice”
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Movement and distribution moulds
Construction Joints
ARCHITECTURAL
CONCRETE??
Vertical moulds
Movement
El Alma Project,
V&A, 2008
Horizontal moulds
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Embedded pipes in reinforced concrete
elements
Slab
Wall
CONCLUSIONS
Cover failure
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¡ Thanks !
Dr. Carlos Videla
October, 2012
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