Transcript LESSONS LEARNED FROM FAILURE OF CONCERETE STRUCTURES

LESSONS LEARNED FROM FAILURE
OF CONCERETE STRUCTURES
Introduction
Studying structural failure case studies is a way of studying the history of the
engineering profession. Typical calculations for design are based on predicting
and avoiding failure. The factor of safety is used to avoid failures, but
knowledge of past failures will better equip an engineer to steer clear of future
failures. It is not only important to know what caused the failure, but also to
understand how it occurred and how to avoid the problem in the future.
This failure study will make you a better Structural Engineer.
VASUDEO PANDYA P.E. ; S.E.
• Family Status: Married
• Educational Qualification :
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B.E. (Civil) Birla Engineering College (BITS), Pilani
MS (Structural) University of Wisconsin, Madison, USA
• Professional Career Summary:
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I have worked on large Oil Refinery and Thermal Power Plant
Projects for last 25 years in USA.
• Professional Achievement/special knowledge:
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License Professional Engineer (P.E.)
License Structural Engineer (S.E.) in U.S.
• Special Interest:
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Peer Review/Checking (Structural ) of projects designed in
house or designed by out side consulting companies. Sharing
my experience with you Young Engineers (Mentoring).
Professionalism in Engineering
Here I produce Professionalism as defined in
"Recommended Guidelines For The Practice Of Structural Engineering in California". Fifth Edition
September 1999. By Professional Practice Committee of Structural Engineers Association Of
California (SEAOC), Section 2 , Pages 1-2 thru 1-4.
2. PROFESSIONALISM
2.1 General: The essence of professionalism is integrity and honesty. Engineers should maintain
ethical and professional standards when performing structural Engineering Services.
2.2 Obligation to the Public: When performing structural engineering services, an engineer should:
2.2.1 Endeavor to protect the general health and safety of the public, as well as fulfill obligations to
clients.
2.2.2 Perform services only within the engineer’s area of expertise.
2.2.3 Perform services in an objective, honest, and impartial manner, basing decisions on education,
analysis, knowledge, experience, and sound engineering judgment
2.2.4 Issue public statements in an objective and a truthful manner.
2.2.5 Refer deceit, misrepresentation, violation of contract, fraud, negligence, or incompetency of
others performing Structural Engineering services to the Board of Registration for Professional
Engineers and Land Surveyors. An objective and unbiased approach to referring such acts to the Board
of Registration is important.
2.3 Obligation to the Client: When performing structural engineering services, an Engineer should:
2.3.1 Act faithfully and honestly in the client’s best interest, and respect the confidentiality of
information obtain from, and on behalf of, the client.
Professionalism in Engineering ….. Continue
2.3.2 Disclose to the client real and potential conflict of interest prior to performing services for the
client, thus offering the client the opportunity to decide whether a conflict of interest would be
detrimental to the interest of the client.
2.3.3 Solicit professional assignments in an ethical and professional manner.
2.3.4 Accurately represent the engineer’s qualifications and experience.
2.4 Obligation to the Profession:
When performing Structural Engineering services, an Engineer should:
2.4.1 Uphold the integrity and dignity of the profession.
2.4.2 Perform professional services with honesty and fairness.
2.4.3 Actively support professional societies and organizations dedicated to the advancement of
knowledge within the profession.
2.5 Obligation to Colleagues, Employers , and Employees:
When Performing Structural Engineering services, an engineer should:
2.5.1 Act with fairness, honesty, objectivity, and respect in relationship with other engineers.
2.5.2 Recognize and respect the professional contributions of Colleagues, employers, and
employees.
2.5.3 Render an opinion of the work of another engineer based upon an unbiased, comprehensive
evaluation of the work, recognizing that there may be alternate methods used to achieve
acceptable results.
Emerging Issues in Structural Engineering
• Emerging Issues
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Structural engineers have a uniquely significant responsibility for
protecting the public relative to the other design disciplines.
Architectural, mechanical, and electrical system failures usually result
in unattractiveness, poor functionality, discomfort and/or
inconvenience. A structural system failure almost always has more
serious consequences, even in the best cases, there are often
substantial costs associated with correcting what is or could become a
life-threatening situation. As a result, professional liability insurance
rates for structural engineers have been increasing, leading to the
creation of the Risk Management Program (RMP). In addition, efforts
are underway to establish board certification at the national level and
expand separate licensure at the state level to "raise the bar" of
qualifications to practice structural engineering.
Blast resistance , Progressive/Disproportionate collapse, of structures.
Fire resistance design of structures.
Learning from failure/ collapse of structures.
RESPONSIBILITY OF A STRUCTURAL ENGINEER
OF RECORD (SER)
For a time being think that you have your consulting firm in some city in USA.
In USA as compared to India, Liability Laws are very strong. That’s my opinion.
You firm designed one of the three recently failed structures (See recent
postings in SEFI) in India.
1) A Chimney Failure.
2) A Coal Bunker Failure.
3) Jalandhar Factory Collapse. 20 died, 75 Injured.
Client ( Owner) of these Plants will sue your firm. There will be expert
witnesses in the court. Finally Court decides that this was a Design/Detailing
flaw. Court will order Heavy penalties (Money awards for damages). Also you as
a HOD(Civil/Structural) or MD of your firm will loose your P.E. or S.E. license to
practice Structural Engineering. With this, my best guess is you will not be in
business of Structural Engineering anymore .
Sorry to point such a bleak picture but this is the way Structural Engineering is
practice in USA. Liability, taking responsibility of mistakes and when required
paying heavy court fines are always expected from us engineers.
So my advice to you is when you submit a project proposal have enough Man
Hrs to implement Quality Assurance using these Industry Standards from USA.
Failure of Structures Education in India
• FAILURE OF STRUCTURES EDUCATION.
With the attached web link and attach file see need for such FAILURE OF
STRUCTURES EDUCATION in Indian Universities for B.E. (Civil) and M.E
(Civil) and also for professional/working civil engineers like us.
http://www.structuremag.org/article.aspx?articleID=336
Failure of Structures Education (Courses) and Problems in India
• 4th April 2012
Learning from failures is a very important
facet of engineering education. Unfortunately,
this is ignored in all our engineering colleges,
the IITs included. It's high time this gap is
bridged.
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Indrajit Barua.
Failure of Structures Education (Courses) and Problems in India
• From a posting in SEFI by Prof. Arc.
“I agree with you 100% that it is very useful to know why a
structure has failed as important results are learnt from such
studies.
The problem [definitely in INDIA] is such information may not
be available for wide circulation fearing witch hunt.
There has to be legal immunity
If you have access to any information on failure of structures
in INDIA, please provide web link”.
Failure of Structures Education(Courses) and Problems in India
• Dear SEFIANs,i tried to get hold of a failure
report of one of the chimney failures in India.
The report is in the safe hands of police and
judiciary but is never allowed to be seen by
engineering fraternity. And everybody expects
failures should be mitigated.
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regards
murali
Failure of Structures Education (Courses) and Problems in India
• The bunker of the 6th unit of the Kahalgaon
Thermal Power Station in Bhagalpur district
collapsed on Sunday halting power generation
from the unit with 500 MW capacity.
Source : News Report
regards
bijay sarkar
Delhi Metro Concrete Pier Failure
I found this important recent failure in India from Google web search.
This DMRC failure was also published in ENR (Engineering News Record) of USA.
Delhi Metro Mishap: DMRC, Gammon Responsible.
The four-member panel that went into the July 12 Metro mishap has fixed responsibility
on the DMRC and contractor Gammon for the accident and recommended the
reconstruction or modification of four pier caps near the Zamrudpur construction site.
In a 11-page report, the panel headed by IIT Professor A K Nagpal said, there was a
departure at site from the requirements of the design in the application of grout to the
interface between the end plates of the steel strut and the face of the pier/pier cap to
which the plates are attached.
"The drawings followed on site for construction of Pier 67 were advance copies and not
authenticated by DMRC's design section. On enquiry, it was found that on occasions
work commences without 'Good for Construction' signed drawings to avoid delayed
construction," the report said.
It also recommended the "reconstruction of or modifications to pier caps 54, 66, 67 and
68 to a revised design configuration."
The July 12 incident at Zamrudpur where an under-construction metro bridge collapsed
due to "design fault" in pier 67 killed seven people.
The panel also asked the DMRC to strengthen its design review system to ensure that
rigorous checking of special structures is carried out in future and that certified drawings
are made a prerequisite for construction to proceed.
Delhi Metro Concrete Pier Failure …… continue
The report also said that unconditional "no objection" was not obtained for the permanent
works drawings prior to construction, which should have been the practice for structures of
such a special nature.
"The contractor (Gammon India) did not ensure that 'good for construction' status with
appropriate certification by DMRC was achieved prior to constructing the works," the report
said and added that there is concern regarding the sample test recording by the contractor
and witnessing of the same by DMRC.
"The consistency of concrete sample test results is highly abnormal. This raises doubts
over the authenticity of the records submitted," the report said.
The panel concluded that deficiencies in material, design and failure to carry out material
testing at the time of appearance of the first cracks and deferral of the load test were the
causes of the accident.
It also said both the temporary works and permanent works designers should be required
to check the material and workmanship of special structures at site to certify compliance
with design intent prior to application of loads on temporary works assemblies and prior to
pouring concrete at permanent works locations.
Show Reliance Industries Slides.
Earthquakes and Structural Engineers
• Relate this to Bhuj Earthquake of 2001 in Gujarat:
• http://www.pptnetwork.net/?query=bhuj+earthquake+ppt
• Dear SEFIN'S:
I watch "NDTV" documentary today 23/09/2011 evening "Agar Delhi Hili
Hoti". That was for a Structural Engineer like me walking through a
dangerous land. That was riveting. Work is cut out for us. What else to
say. We should all ask for a copy of it and see it. Delhi is Seismic Zone IV
and that TV documentary scare's me, a Structural Engineer like nothing
else.
TIMES OF INDIA " Editorial " on Earthquake preparedness says it all,
Titled. WAKE UP CALL:
Sep 21, 2011, 12.54am IST
Earthquakes and Structural Engineers.. Continue
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TIMES OF INDIA " Editorial " on Earthquake preparedness says it all,
Titled. WAKE UP CALL:
Sep 21, 2011, 12.54am IST
Himalayan Earthquake
With the death toll climbing to at least 80, the recent Himalayan earthquake is an
urgent wake-up call for all concerned — the government, policymakers and law
enforcers. The effects of the 6.8 magnitude earthquake were felt across as many as
six northern and eastern Indian states. The scale of devastation in its trail has raised
critical concerns about India's preparedness to deal with quakes of much greater
intensity. That Japan experienced earthquakes this year measuring 8.9 on the
Richter scale — releasing energy a thousand times greater than the current
Himalayan quake — should serve as a sober reminder.
Given that over 58.6% of land in India is vulnerable to tremors, the National Disaster
Management Authority (NDMA) has identified quakes as a major issue of concern.
As many as 38 of India's cities, including Delhi, Kolkata, Mumbai, Chennai, Pune and
Ahmedabad, fall within moderate-to-high risk seismic zones. Put simply, an
earthquake on the scale that Japan experienced would lay waste whole cities here. It
is well known that quakes do not kill people, buildings do. Safety essentially lies in
ensuring quake-resistant construction of buildings. There already exists a host of
safety regulations on paper. The NDMA has mandated all new constructions to be
earthquake-resistant, especially in seismic zone cities.
Earthquakes and Structural Engineers.. Continue
Earthquake engineering codes and quake-safe construction guidelines have been
laid down by government bodies. But the real worry is about their enforcement.
Illegal and poor quality constructions continue to be the bane of urban India,
coupled with a crippling lack of awareness regarding safety norms. Structural
engineers have criticized city authorities for flouting regulations and risking lives.
Behind the shoddy construction is murky collusion between real estate and
municipal authorities, mired in corruption and rule bending.
India needs to draw lessons from Japan, which has stringently enforced strict
building codes, put into effect a functional warning system and conducted regular
drills among people. The Himalayan quake is a reminder to get our act together.
Besides enforcing building codes, important infrastructure such as arterial roads
and airports needs to be fortified. Community-level preparedness could drastically
reduce the loss of lives and property. Education and information are two vital
conduits for spreading awareness. The government`s resource material on quakes
should be widely disseminated and discussed at every forum, starting with schools.
Disaster management is already part of the social sciences school syllabus.
Regular drills can help prepare children to deal with sudden situations. It is the
extent of disaster preparedness which will help India protect itself from quake
devastation.
Failure of concrete Structures….. Tower of Pisa
Introduction
The Leaning Tower of Pisa is the freestanding bell tower of
the cathedral of the Italian city of Pisa. It is situated behind
the Cathedral and is the third oldest structure in Pisa’s
Cathedral Square. The tower is about 60 m (200 ft) tall from
foundation to belfry, 19.6 m in (66 ft) in diameter and
weighs approximately 145 MN (14,500 tons). Its foundation
is inclined at almost 5.5 degrees to the south; the tower
overhangs the ground about 4.5 m (20 ft) out of plumb.
Today its inclination is about 10%; the value corresponding
to the eccentricity on the loads on the foundation is 2.3 m.
Lessons
The failure of the Tower of Pisa is without doubt unique for
a number of reasons ranging from the fact that it is a failure
that has been occurring essentially on a continuous basis
for more than 800 years. Despite the extensive
investigations and analyses conducted over the past 60
years, there is still no consensus on the cause of failure.
What is significant however is that finally, after 8 centuries,
the condition of the tower has been improved.
For more details use web link…
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http://matdl.org/failurecases/Building_Collapse_Case
s/Tower_of_Pisa
Failure of concrete Structures…..
Introduction
Studying structural failure case studies is a way of studying the history of the
engineering profession. Typical calculations for design are based on predicting
and avoiding failure. The factor of safety is used to avoid failures, but
knowledge of past failures will better equip an engineer to steer clear of
future failures. It is not only important to know what caused the failure, but
also to understand how it occurred and how to avoid the problem in the
future.
In the collapse at 2000 Commonwealth Avenue, Boston, Massachusetts on
January 25, 1971, punching shear failure is believed to have triggered the
collapse of two thirds of the 16-story concrete building during construction.
But an investigation called for by the mayor proved that there were many
flaws in the design of the apartment building. It is important to remind
engineers about past failures, such as this one, so that history does not
repeat itself.
2000 Commonwealth Avenue, Boston Massachusetts (January 25, 1971)
Failed Building
Designed Building
2000 Commonwealth Avenue, Boston Massachusetts (January 25, 1971)
SHEAR MECHANISMS AND FAILURES
Shear in reinforced concrete can be a complex subject for students to grasp. First of all, the flow of forces
can be difficult to visualize. Second, while the need to use stirrup reinforcement to enhance shear
strength is straightforward, the need to provide minimum stirrups when the calculated forces show that
they aren’t necessary is not so obvious.
Two case studies illustrate the collapse of buildings under construction due to punching shear and similar
mechanisms. The first of the two was the January 25, 1971 collapse of the 2000 Commonwealth Avenue
apartment building under construction in Boston. Four workers were killed in this collapse. The project
was characterized by an almost total lack of construction control and inspection.
The floor plan and the extent of collapse are shown in Fig 1.
2000 Commonwealth Avenue, Boston Massachusetts (January 25, 1971)
This building used flat plate construction. A plate is a slab of uniform thickness supported on columns.
This is a very economical type of construction for short spans and light loads because formwork is very simple and
the absence of beams reduces the floor-to-floor height (p. 606, Wight and MacGregor, 2009) 3. However, the
problem with the system is that it is subject to two-way or punching shear of the slabs, which can be a brittle failure
mechanism. Despite the importance of this failure mechanism, textbooks often suggest that the material not be
covered in an introductory course but be deferred to an advanced course.
Prof. Delatte
The punching shear mechanism is illustrated in Fig. 2. The slab breaks away and the column “punches”
through the slab. The resistance to punching shear depends on the strength of the concrete, the effective depth of the
slab, and the perimeter of the failure plane around the column. Clearly, the loads applied to the slab and the removal
of shoring under the slab are also important. In the collapse at 2000 Commonwealth Avenue, the strength of the
concrete was low and strength development was impaired by cold weather. Some of the reinforcement was
improperly placed and poorly developed. The roof slab of the building held heavy mechanical equipment, and there
was evidence that shoring had been removed prematurely.
2000 Commonwealth Avenue, Boston Massachusetts (January 25, 1971)
Lesson learned:
Unfortunately, 2000 Commonwealth Avenue would not be the last project that suffered from
faulty construction practices leading to a punching shear failure and progressive collapse of the
building. Skyline Plaza was one of the first major failures to follow Commonwealth Avenue.
Similar to the collapse in Boston this 30 story concrete structure failed due to early removal of
shores, insufficient concrete strength, and improper construction planning. Harbour Bay
Condominium was another case of a building project that resulted in a collapse during
construction. Again procedural errors were largely to blame leading to a punching shear failure
and progressive collapse during construction. Immediately following the collapse a summary of
the failure at Commonwealth Avenue was available but the details were not widely known.
Skyline Plaza and Harbour Bay both could have benefitted from the timely dissemination of
information about this failure. For a further discussion of similar failures please review Concrete
System Collapses and Failures During Construction.
For more details use web link…
http://matdl.org/failurecases/Building_Collapse_Cases/2000_Commonwealth
Building Collapse Cases/Skyline Plaza at Bailey's Crossroad
Building Collapse Cases/Skyline Plaza at Bailey's Crossroad
Introduction:
On March 2, 1973, the Skyline Plaza apartment building in Bailey’s Crossroads, Virginia collapsed while
under construction. The collapse extended vertically through the building from the 24th floor to the
ground, leaving an appearance of the structure as two different high rise buildings with a gap between
them. The collapse tore a sixty-foot (18 m) wide gap through the building all the way to the ground. At the
time of the collapse, two practically identical reinforced concrete towers had already been built
(Kaminetzky 1991, p. 64). The collapse occurred at about 2:30 pm (Leyendecker and Fattal 1977 pg. 2).
Structural Analysis:
At the time of the collapse, three dimensional elastic finite element (FE) analysis using computers was still
a relatively new technology. The NBS investigation team used FE analysis to evaluate the slab stresses in
the region where the collapse occurred, using beam and plate elements. Stresses were compared to the
provisions of ACI 318-71 (ACI 1971). Three different cases were analyzed, with different shoring and
concrete conditions. Yield line analysis was also used. The results showed that even with low concrete
strength, a flexural failure of the slab would be unlikely. However, under any of the cases where shores
had been removed, a punching shear failure of the slab would probably occur. Once punching shear
occurred at any one column, the collapse would rapidly propagate as other slab-column joints became
overstressed. There was no indication that the crane was a contributing factor to the collapse (pp. 65 – 83,
Leyendecker and Fattal, 1977).
It should also be noted that by the ACI code (ACI 1971), sand-lightweight concrete has a 15 % lower shear
strength than conventional concrete for the same compressive strength. The most critical locations for
punching shear were found to be at columns 67, 68, 83, and 84 (Carino et al., 1983)
Building Collapse Cases/Skyline Plaza at Bailey's Crossroad
Lesson learned:
“The NBS investigation concluded that the probable cause of the collapse was a punching
shear failure of the 23rd floor… The premature removal of forms supporting the 23rd story
slab when the concrete of that slab had a relatively low strength produced shear stresses
in excess of the concrete capacity at the time of the incident… Most of the eyewitness
reports indicated deflection in the 23rd and 24th story slabs [varying from 6 in. to 2 ft.
(152 mm to 0.6 m)] which increased over a 15 or 20 min time period before failure… The
loss of support from any one of these columns led to overstressing of the slab around the
remaining columns and the failure propagated through the 23rd floor until a stable
configuration remained. The accumulation and impact of falling debris from the collapsing
23rd and 24th floors overloaded the 22nd floor slab and induced the progressive collapse
of successive floors down to the ground” (Carino et al. 1983, p. 41).
Building Collapse Cases/Skyline Plaza at Bailey's Crossroad
Lesson learned: (continued….)
Kaminetzky (1991, p. 67) cites six lessons from this case:
The contractor should be responsible for preparing formwork drawings, including shores and reshores
The contractor should prepare a detailed concrete testing plan for stripping forms, including cylinder
tests
Inspectors and other quality control agencies should verify that the contractor performs the above two
items
The EOR should make sure he/she provides the contractor with all necessary design load data and other
unique project information
“Uncontrolled acceleration of formwork removal” may cause a total or partial collapse
Continuous top and bottom slab reinforcement is necessary around the columns. Continuous
reinforcement provides overall ductility.
If the contractor uses cylinder tests to determine when to strip forms during cold weather, the cylinders
should be stored at the same ambient temperature as the structure. This will prevent overestimation of
the in-place concrete strength.
For more details use web link…
http://matdl.org/failurecases/Building_Collapse_Cases/Skyline_Plaza_at_Bailey%27s_Crossroad
WEB LINK FOR MORE FAILURE CASES
• WEB LINK FOR MORE FAILURE CASES :
SELECT THE FAILURE CASES AND STUDY WELL. Will make you a better
Structural Engineer. Try to collect reliable information on Failure of
Structures in India (Chimney’s , Coal Bunkers, Buildings) and learn from
them.
• http://matdl.org/failurecases/
• Show ACI SP-284-4 slides. Learning from Failures in Concrete Design and
Construction. By Dr. Norbert Delatte .
Thanks.
• Thanks for listening. Best wishes for your
career.