California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Ethics Across The Curriculum
Case Studies # 1-The Space Shuttle Challenger Disaster
Introduction To The Case
On January 28, 1986, seven astronauts were killed when the space shuttle they were piloting, the
Challenger, exploded just over a minute into the flight (Figure 1). The failure of the solid rocket
booster O-rings to seat properly allowed hot combustion gases to leak from the side of the booster
and burn through the external fuel tank. The failure of the O-ring was attributed to several factors,
including faulty design of the solid rocket boosters, insufficient low- temperature testing of the
O-ring material and the joints that the O-ring sealed, and lack of proper communication between
different levels of NASA management.
Figure 1. The Space Shuttle Challenger Disaster
Instructor Guidelines
Prior to class discussion, ask the students to read the student handout outside of class. In
class the details of the case can be reviewed with the aide of the overheads. Reserve about half of
the class period for an open discussion of the issues. The issues covered in the student handout
include the importance of an engineer's responsibility to public welfare, the need for this
responsibility to hold precedence over any other responsibilities the engineer might have and the
responsibilities of a manager/engineer. A final point is the fact that no matter how far removed
from the public an engineer may think she is, all of her actions have potential impact.
Background
NASA managers were anxious to launch the Challenger (Figure 2) for several reasons, including
economic considerations, political pressures, and scheduling backlogs. Unforeseen competition
from the European Space Agency put NASA in a position where it would have to fly the shuttle
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
dependably on a very ambitious schedule in order to prove the Space Transportation System's cost
effectiveness and potential for commercialization. This prompted NASA to schedule a record
number of missions in 1986 to make a case for its budget requests. The shuttle mission just prior to
the Challenger had been delayed a record number of times due to inclement weather and
mechanical factors. NASA wanted to launch the Challenger without any delays so the launch pad
could be refurbished in time for the next mission, which would be carrying a probe that would
examine Halley's Comet. If launched on time, this probe would have collected data a few days
before a similar Russian probe would be launched. There was probably also pressure to launch
Challenger so it could be in space when President Reagan gave his State of the Union address.
Reagan's main topic was to be education, and he was expected to mention the shuttle and the first
teacher in space, Christa McAuliffe. The shuttle solid rocket boosters (or SRBs) (Figure 3), are key
elements in the operation of the shuttle. Without the boosters, the shuttle cannot produce enough
thrust to overcome the earth's gravitational pull and achieve orbit. There is an SRB attached to
each side of the external fuel tank. Each booster is 149 feet long and 12 feet in diameter. Before
ignition, each booster weighs 2 million pounds. Solid rockets in general produce much more thrust
per pound than their liquid fuel counterparts. The drawback is that once the solid rocket fuel has
been ignited, it cannot be turned off or even controlled. So it was extremely important that the
shuttle SRBs were properly designed. Morton Thiokol was awarded the contract to design and
build the SRBs in 1974. Thiokol's design is a scaled-up version of a Titan missile which had been
used successfully for years. NASA accepted the design in 1976. The booster is comprised of seven
hollow metal cylinders. The solid rocket fuel is cast into the cylinders at the Thiokol plant in Utah,
and the cylinders are assembled into pairs for transport to Kennedy Space Center in Florida. At
KSC, the four booster segments are assembled into a completed booster rocket. The joints where
the segments are joined together at KSC are known as field joints (See Figure 4). These field joints
consist of a tang and clevis joint. The tang and clevis are held together by 177 clevis pins. Each
joint is sealed by two O rings, the bottom ring known as the primary O-ring, and the top known as
the secondary O-ring. (The Titan booster had only one O-ring. The second ring was added as a
measure of redundancy since the boosters would be lifting humans into orbit. Except for the
increased scale of the rocket's diameter, this was the only major difference between the shuttle
booster and the Titan booster.) The purpose of the O-rings is to prevent hot combustion gasses
from escaping from the inside of the motor. To provide a barrier between the rubber O-rings and
the combustion gasses, a heat resistant putty is applied to the inner section of the joint prior to
assembly. The gap between the tang and the clevis determines the amount of compression on the
O-ring. To minimize the gap and increase the squeeze on the O-ring, shims are inserted between
the tang and the outside leg of the clevis.
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Figure 2. Space Shuttle
Figure 3. Solid Rocket Booster
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© Assistant Prof. Y.F. Ko, P.E.
California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Figure 4. Field Joint of Solid Rocket Booster
Questions for Class Discussion
1. What could NASA management have done differently?
2. What, if anything, could their subordinates have done differently?
3. What should Roger Boisjoly have done differently (if anything)? In answering this question,
keep in mind that at his age, the prospect of finding a new job if he was fired was slim. He also
had a family to support.
4. What do you (the students) see as your future engineering professional responsibilities in
relation to both being loyal to management and protecting the public welfare?
The Challenger Disaster Overheads
1. Organizations/People Involved
2. Key Dates
3. Space Shuttle Solid Rocket Boosters (SRB) Joints
4. Detail of SRB Field Joints
5. Ballooning Effect of Motor Casing
6. Key Issues
ORGANIZATIONS/PEOPLE INVOLVED
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Marshall Space Flight Center - in charge of booster rocket development
Larry Mulloy - challenged the engineers' decision not to launch
Morton Thiokol - Contracted by NASA to build the Solid Rocket Booster
Alan McDonald - Director of the Solid Rocket Motors Project
Bob Lund - Engineering Vice President
Robert Ebeling - Engineer who worked under McDonald
Roger Boisjoly - Engineer who worked under McDonald
Joe Kilminster - Engineer in a management position
Jerald Mason - Senior executive who encouraged Lund to reassess his decision not to launch.
KEY DATES
1974 - Morton-Thiokol awarded contract to build solid rocket boosters.
1976 - NASA accepts Morton-Thiokol's booster design.
1977 - Morton-Thiokol discovers joint rotation problem. November 1981 - O-ring erosion
discovered after second shuttle flight.
January 24, 1985 - shuttle flight that exhibited the worst O-ring blow-by.
July 1985 - Thiokol orders new steel billets for new field joint design.
August 19, 1985 - NASA Level I management briefed on booster problem.
January 27, 1986 - night teleconference to discuss effects of cold temperature on booster
performance.
January 28, 1986 - Challenger explodes 72 seconds after liftoff.
KEY ISSUES
1. HOW DOES THE IMPLIED SOCIAL CONTRACT OF PROFESSIONALS APPLY TO THIS
CASE?
2. WHAT PROFESSIONAL RESPONSIBILITIES WERE NEGLECTED, IF ANY?
3.SHOULD NASA HAVE DONE ANYTHING DIFFERENTLY IN THEIR LAUNCH
DECISION PROCEDURE?
Case Studies # 1-The Space Shuttle Challenger Disaster
Discussion Answer Sheets
Questions for Class Discussion
5. What could NASA management have done differently?
Case Studies # 1-The Space Shuttle Challenger Disaster
Student Handout - Synopsis
On January 28, 1986, seven astronauts were killed when the space shuttle they were piloting, the
Challenger, exploded just over a minute into flight. The failure of the solid rocket booster O-rings
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
to seat properly allowed hot combustion gases to leak from the side of the booster and burn
through the external fuel tank. The failure of the O-ring was attributed to several factors, including
faulty design of the solid rocket boosters, insufficient low temperature testing of the O-ring
material and the joints that the O-ring sealed, and lack of communication between different levels
of NASA management.
Organization and People Involved
Marshall Space Flight Center - in charge of booster rocket development
Larry Mulloy - challenged the engineers' decision not to launch
Morton Thiokol - Contracted by NASA to build the Solid Rocket Booster
Alan McDonald - Director of the Solid Rocket Motors Project
Bob Lund - Engineering Vice President
Robert Ebeling - Engineer who worked under McDonald
Roger Boisjoly - Engineer who worked under McDonald
Joe Kilminster - Engineer in a management position
Jerald Mason - Senior Executive who encouraged Lund to reassess his decision not to launch.
Key Dates
1974 - Morton-Thiokol awarded contract to build solid rocket boosters.
1976 - NASA accepts Morton-Thiokol's booster design.
1977 - Morton-Thiokol discovers joint rotation problem. November 1981 - O-ring erosion
discovered after second shuttle flight. January 24, 1985 - shuttle flight that exhibited the worst
O-ring blow-by. July 1985 - Thiokol orders new steel billets for new field joint design.
August 19, 1985 - NASA Level I management briefed on booster problem.
January 27, 1986 - night teleconference to discuss effects of cold temperature on booster
performance.
January 28, 1986 - Challenger explodes 72 seconds after liftoff.
Background
NASA managers were anxious to launch the Challenger (Figure 1) for several reasons, including
economic considerations, political pressures, and scheduling backlogs. Unforeseen competition
from the European Space Agency put NASA in a position where it would have to fly the shuttle
dependably on a very ambitious schedule in order to prove the Space Transportation System's cost
effectiveness and potential for commercialization. This prompted NASA to schedule a record
number of missions in 1986 to make a case for its budget requests. The shuttle mission just prior to
the Challenger had been delayed a record number of times due to inclement weather and
mechanical factors. NASA wanted to launch the Challenger without any delays so the launch pad
could be refurbished in time for the next mission, which would be carrying a probe that would
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
examine Halley's Comet. If launched on time, this probe would have collected data a few days
before a similar Russian probe would be launched. There was probably also pressure to launch
Challenger so it could be in space when President Reagan gave his State of the Union address.
Reagan's main topic was to be education, and he was expected to mention the shuttle and the first
teacher in space, Christa McAuliffe. The shuttle solid rocket boosters (or SRBs) (Figure 2), are key
elements in the operation of the shuttle. Without the boosters, the shuttle cannot produce enough
thrust to overcome the earth's gravitational pull and achieve orbit. There is an SRB attached to
each side of the external fuel tank. Each booster is 149 feet long and 12 feet in diameter. Before
ignition, each booster weighs 2 million pounds. Solid rockets in general produce much more thrust
per pound than their liquid fuel counterparts. The drawback is that once the solid rocket fuel has
been ignited, it cannot be turned off or even controlled. So it was extremely important that the
shuttle SRBs were properly designed. Morton Thiokol was awarded the contract to design and
build the SRBs in 1974. Thiokol's design is a scaled-up version of a Titan missile which had been
used successfully for years. NASA accepted the design in 1976. The booster is comprised of seven
hollow metal cylinders. The solid rocket fuel is cast into the cylinders at the Thiokol plant in Utah,
and the cylinders are assembled into pairs for transport to Kennedy Space Center in Florida. At
KSC, the four booster segments are assembled into a completed booster rocket. The joints where
the segments are joined together at KSC are known as field joints (See Figure 3). These field joints
consist of a tang and clevis joint. The tang and clevis are held together by 177 clevis pins. Each
joint is sealed by two O rings, the bottom ring known as the primary O-ring, and the top known as
the secondary O-ring. (The Titan booster had only one O-ring. The second ring was added as a
measure of redundancy since the boosters would be lifting humans into orbit. Except for the
increased scale of the rocket's diameter, this was the only major difference between the shuttle
booster and the Titan booster.) The purpose of the O-rings is to prevent hot combustion gasses
from escaping from the inside of the motor. To provide a barrier between the rubber O-rings and
the combustion gasses, a heat resistant putty is applied to the inner section of the joint prior to
assembly. The gap between the tang and the clevis determines the amount of compression on the
O-ring. To minimize the gap and increase the squeeze on the O-ring, shims are inserted between
the tang and the outside leg of the clevis.
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Figure 1. Space Shuttle
Figure 2. Solid Rocket Booster
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© Assistant Prof. Y.F. Ko, P.E.
California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Figure 3. Field Joint of Solid Rocket Booster
Figure 4. Field Joint Rotation of Solid Rocket Booster
Launch Delays
The first delay of the Challenger mission was because of a weather front expected to move into the
area, bringing rain and cold temperatures. Usually a mission wasn't postponed until inclement
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
weather actually entered the area, but the Vice President was expected to be present for the launch
and NASA officials wanted to avoid the necessity of the Vice President's having to make an
unnecessary trip to Florida; so they postponed the launch early. The Vice President was a key
spokesperson for the President on the space program, and NASA coveted his good will. The
weather front stalled, and the launch window had perfect weather conditions; but the launch had
already been postponed to keep the Vice President from unnecessarily traveling to the launch site.
The second launch delay was caused by a defective micro switch in the hatch locking mechanism
and by problems in removing the hatch handle. By the time these problems had been sorted out,
winds had become too high. The weather front had started moving again, and appeared to be
bringing record-setting low temperatures to the Florida area. NASA wanted to check with all of its
contractors to determine if there would be any problems with launching in the cold temperatures.
Alan McDonald, director of the Solid Rocket Motor Project at Morton-Thiokol, was convinced
that there were cold weather problems with the solid rocket motors and contacted two of the
engineers working on the project, Robert Ebeling and Roger Boisjoly. Thiokol knew there was a
problem with the boosters as early as 1977, and had initiated a redesign effort in 1985. NASA
Level I management had been briefed on the problem on August 19, 1985. Almost half of the
shuttle flights had experienced O-ring erosion in the booster field joints. Ebeling and Boisjoly had
complained to Thiokol that management was not supporting the redesign task force.
Engineering Design
The size of the gap is controlled by several factors, including the dimensional tolerances of the
metal cylinders and their corresponding tang or clevis, the ambient temperature, the diameter of
the O-ring, the thickness of the shims, the loads on the segment, and quality control during
assembly. When the booster is ignited, the putty is displaced, compressing the air between the
putty and the primary O-ring in volume v1 of Figure 3. The air pressure forces the O-ring into the
gap between the tang and clevis. Pressure loads are also applied to the walls of the cylinder,
causing the cylinder to balloon slightly as shown in Figure 3. (The ballooning effect has been
greatly exaggerated.) This ballooning of the cylinder walls caused the gap between the tang and
clevis gap to open. This effect has come to be known as joint rotation. Morton-Thiokol discovered
this joint rotation as part of its testing program in 1977. Thiokol discussed the problem with NASA
and started analyzing and testing to determine how to increase the O-ring compression, thereby
decreasing the effect of joint rotation (Figure 4). Three design changes were implemented:
1. Dimensional tolerances of the metal joint were tightened.
2. The O-ring diameter was increased, and its dimensional tolerances were tightened.
3. The use of the shims mentioned above was introduced. Further testing by Thiokol revealed that
the second seal, in some cases, might not seal at all. Additional changes in the shim thickness
and O-ring diameter were made to correct the problem.
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
A new problem was discovered during November 1981, after the flight of the second shuttle
mission. Examination of the booster field joints revealed that the O-rings were eroding during
flight. The joints were still sealing effectively, but the O-ring material was being eaten away by hot
gasses that escaped past the putty. Thiokol studied different types of putty and its application to
study their effects on reducing O-ring erosion. The shuttle flight 51-C of January 24, 1985, was
launched during some of the coldest weather in Florida history. Upon examination of the booster
joints, engineers at Thiokol noticed black soot and grease on the outside of the booster casing,
caused by actual gas blow-by. This prompted Thiokol to study the effects of O-ring resiliency at
low temperatures. They conducted laboratory tests of O-ring compression and resiliency between
50lF and 100lF. In July 1985, Morton Thiokol ordered new steel billets which would be used for a
redesigned case field joint. At the time of the accident, these new billets were not ready for
Thiokol, because they take many months to manufacture.
The Night Before the Launch
Temperatures for the next launch date were predicted to be in the low 20°s. This prompted Alan
McDonald to ask his engineers at Thiokol to prepare a presentation on the effects of cold
temperature on booster performance. A teleconference was scheduled the evening before the
re-scheduled launch in order to discuss the low temperature performance of the boosters. This
teleconference was held between engineers and management from Kennedy Space Center,
Marshall Space Flight Center in Alabama, and Morton-Thiokol in Utah. Boisjoly and another
engineer, Arnie Thompson, knew this would be another opportunity to express their concerns
about the boosters, but they had only a short time to prepare their data for the presentation.1
Thiokol's engineers gave an hour-long presentation, presenting a convincing argument that the
cold weather would exaggerate the problems of joint rotation and delayed O-ring seating. The
lowest temperature experienced by the O-rings in any previous mission was 53°F, the January 24,
1985 flight. With a predicted ambient temperature of 26°F at launch, the O-rings were estimated to
be at 29°F. After the technical presentation, Thiokol's Engineering Vice President Bob Lund
presented the conclusions and recommendations. His main conclusion was that 53°F was the only
low temperature data Thiokol had for the effects of cold on the operational boosters. The boosters
had experienced O-ring erosion at this temperature. Since his engineers had no low temperature
data below 53°F, they could not prove that it was unsafe to launch at lower temperatures. He read
his recommendations and commented that the predicted temperatures for the morning's launch was
outside the data base and NASA should delay the launch, so the ambient temperature could rise
until the O-ring temperature was at least 53°F. This confused NASA managers because the booster
design specifications called for booster operation as low as 31°F. (It later came out in the
investigation that Thiokol understood that the 31°F limit temperature was for storage of the booster,
and that the launch temperature limit was 40°F. Because of this, dynamic tests of the boosters had
never been performed below 40°F.) Marshall's Solid Rocket Booster Project Manager, Larry
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Mulloy, commented that the data was inconclusive and challenged the engineers' logic. A heated
debate went on for several minutes before Mulloy bypassed Lund and asked Joe Kilminster for his
opinion. Kilminster was in management, although he had an extensive engineering background. By
bypassing the engineers, Mulloy was calling for a middle-management decision, but Kilminster
stood by his engineers. Several other managers at Marshall expressed their doubts about the
recommendations, and finally Kilminster asked for a meeting off of the net, so Thiokol could
review its data. Boisjoly and Thompson tried to convince their senior managers to stay with their
original decision not to launch. A senior executive at Thiokol, Jerald Mason, commented that a
management decision was required. The managers seemed to believe the O-rings could be eroded
up to one third of their diameter and still seat properly, regardless of the temperature. The data
presented to them showed no correlation between temperature and the blow-by gasses which
eroded the O-rings in previous missions. According to testimony by Kilminster and Boisjoly,
Mason finally turned to Bob Lund and said, "Take off your engineering hat and put on your
management hat." Joe Kilminster wrote out the new recommendation and went back on line with
the teleconference. The new recommendation stated that the cold was still a safety concern, but
their people had found that the original data was indeed inconclusive and their "engineering
assessment" was that launch was recommended, even though the engineers had no part in writing
the new recommendation and refused to sign it. Alan McDonald, who was present with NASA
management in Florida, was surprised to see the recommendation to launch and appealed to NASA
management not to launch. NASA managers decided to approve the boosters for launch despite the
fact that the predicted launch temperature was outside of their operational specifications.
The Launch
During the night, temperatures dropped to as low as 8°F, much lower than had been anticipated. In
order to keep the water pipes in the launch platform from freezing, safety showers and fire hoses
had been turned on. Some of this water had accumulated, and ice had formed all over the platform.
There was some concern that the ice would fall off of the platform during launch and might
damage the heat resistant tiles on the shuttle. The ice inspection team thought the situation was of
great concern, but the launch director decided to go ahead with the countdown. Note that safety
limitations on low temperature launching had to be waived and authorized by key personnel
several times during the final countdown. These key personnel were not aware of the
teleconference about the solid rocket boosters that had taken place the night before. At launch, the
impact of ignition broke loose a shower of ice from the launch platform. Some of the ice struck the
left-hand booster, and some ice was actually sucked into the booster nozzle itself by an aspiration
effect. Although there was no evidence of any ice damage to the Orbiter itself, NASA analysis of
the ice problem was wrong. The booster ignition transient started six hundredths of a second after
the igniter fired. The aft field joint on the right-hand booster was the coldest spot on the booster:
about 28°F. The booster's segmented steel casing ballooned and the joint rotated, expanding
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
inward as it had on all other shuttle flights. The primary O-ring was too cold to seat properly, the
cold-stiffened heat resistant putty that protected the rubber O-rings from the fuel collapsed, and
gases at over 5000°F burned past both O-rings across seventy degrees of arc. Eight hundredths of a
second after ignition, the shuttle lifted off. Engineering cameras focused on the right-hand booster
showed about nine smoke puffs coming from the booster aft field joint. Before the shuttle cleared
the tower, oxides from the burnt propellant temporarily sealed the field joint before flames could
escape. Fifty-nine seconds into the flight, Challenger experienced the most violent wind shear ever
encountered on a shuttle mission. The glassy oxides that sealed the field joint were shattered by the
stresses of the wind shear, and within seconds flames from the field joint burned through the
external fuel tank. Hundreds of tons of propellant ignited, tearing apart the shuttle. One hundred
seconds into the flight, the last bit of telemetry data was transmitted from the Challenger.
Issues For Discussion
The Challenger disaster has several issues which are relevant to engineers. These issues raise
many questions which may not have any definite answers, but can serve to heighten the awareness
of engineers when faced with a similar situation. One of the most important issues deals with
engineers who are placed in management positions. It is important that these managers not ignore
their own engineering experience, or the expertise of their subordinate engineers. Often a manager,
even if she has engineering experience, is not as up to date on current engineering practices as are
the actual practicing engineers. She should keep this in mind when making any sort of decision
that involves an understanding of technical matters. Another issue is the fact that managers
encouraged launching due to the fact that there was insufficient low temperature data. Since there
was not enough data available to make an informed decision, this was not, in their opinion,
grounds for stopping a launch. This was a reversal in the thinking that went on in the early years of
the space program, which discouraged launching until all the facts were known about a particular
problem. This same reasoning can be traced back to an earlier phase in the shuttle program, when
upper-level NASA management was alerted to problems in the booster design, yet did not halt the
program until the problem was solved. To better understand the responsibility of the engineer,
some key elements of the professional responsibilities of an engineer should be examined. This
will be done from two perspectives: the implicit social contract between engineers and society, and
the guidance of the codes of ethics of professional societies. As engineers test designs for
ever-increasing speeds, loads, capacities and the like, they must always be aware of their
obligation to society to protect the public welfare. After all, the public has provided engineers,
through the tax base, with the means for obtaining an education and, through legislation, the means
to license and regulate themselves. In return, engineers have a responsibility to protect the safety
and well-being of the public in all of their professional efforts. This is part of the implicit social
contract all engineers have agreed to when they accepted admission to an engineering college. The
first canon in the ASME Code of Ethics urges engineers to "hold paramount the safety, health and
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
welfare of the public in the performance of their professional duties." Every major engineering
code of ethics reminds engineers of the importance of their responsibility to keep the safety and
well being of the public at the top of their list of priorities. Although company loyalty is important,
it must not be allowed to override the engineer's obligation to the public. Marcia Baron, in an
excellent monograph on loyalty, states: "It is a sad fact about loyalty that it
invites...single-mindedness. Single-minded pursuit of a goal is sometimes delightfully romantic,
even a real inspiration. But it is hardly something to advocate to engineers, whose impact on the
safety of the public is so very significant. Irresponsibility, whether caused by selfishness or by
magnificently unselfish loyalty, can have most unfortunate consequences."
Annotated Bibliography and Suggested References
Feynman, Richard Phillips, What Do You Care What Other People Think,: Further Adventures of
a Curious Character, Bantam Doubleday Dell Pub, ISBN 0553347845, Dec 1992. Reference
added by request of Sharath Bulusu, as being pertinent and excellent reading - 8-25-00.
Lewis, Richard S., Challenger: the final voyage, Columbia University Press, New York, 1988.
McConnell, Malcolm, Challenger: a major malfunction, Doubleday, Garden City, N.Y., 1987.
Trento, Joseph J., Prescription for disaster, Crown, New York, c1987.
United States. Congress. House. Committee on Science and Technology, Investigation of the
Challenger accident : hearings before the Committee on Science and Technology, U.S. House of
Representatives, Ninety-ninth Congress, second session .... U.S. G.P.O.,Washington, 1986.
United States. Congress. House. Committee on Science and Technology, Investigation of the
Challenger accident : report of the Committee on Science and Technology, House of
Representatives, Ninety-ninth Congress, second session. U.S. G.P.O., Washington, 1986.
United States. Congress. House. Committee on Science, Space, and Technology, NASA's response
to the committee's investigation of the "Challenger" accident : hearing before the Committee on
Science, Space, and Technology, U.S. House of Representatives, One hundredth Congress, first
session, February 26, 1987. U.S. G.P.O., Washington, 1987.
United States. Congress. Senate. Committee on Commerce, Science, and Transportation.
Subcommittee on Science, Technology, and Space, Space shuttle accident : hearings before the
Subcommittee on Science, Technology, and Space of the Committee on Commerce, Science, and
Transportation, United States Senate, Ninety-ninth Congress, second session, on space shuttle
accident and the Rogers Commission report, February 18, June 10, and 17, 1986. U.S. G.P.O.,
Washington, 1986.
Notes
1. "Challenger: A Major Malfunction." (see above) p. 194.
2. Baron, Marcia. The Moral Status of Loyalty. Illinois Institute of Technology: Center for the
Study of Ethics in the Professions, 1984, p. 9. One of a series of monographs on applied ethics that
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California State University, Long Beach
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© Assistant Prof. Y.F. Ko, P.E.
deal specifically with the engineering profession. Provides arguments both for and against loyalty.
28 pages with notes and an annotated bibliography.
Case Studies # 2-The Kansas City Hyatt Regency Walkways Collapse
~Negligence And The Professional "Debate" Over Responsibility For Design
Introduction To The Case
On July 17, 1981, the Hyatt Regency Hotel in Kansas City, Missouri, held a videotaped tea-dance
party in their atrium lobby. With many party-goers standing and dancing on the suspended
walkways, connections supporting the ceiling rods that held up the second and fourth-floor
walkways across the atrium failed, and both walkways collapsed onto the crowded first-floor
atrium below. The fourth-floor walkway collapsed onto the second-floor walkway, while the offset
third-floor walkway remained intact. As the United States' most devastating structural failure, in
terms of loss of life and injuries, the Kansas City Hyatt Regency walkways collapse left 114 dead
and in excess of 200 injured. In addition, millions of dollars in costs resulted from the collapse,
and thousands of lives were adversely affected.
Figure 1. Aftermath view: The 4th floor and 2nd floor walkways were positioned at the now
boarded entrances. A parallel 3rd floor walkway to the left was left intact
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California State University, Long Beach
Dept. of Civil Eng. and Construction Eng. Management
Spring 2010
© Assistant Prof. Y.F. Ko, P.E.
Figure 2. A major cause of fatalities was the landing of the concrete 4th floor walkway onto
the crowded 2nd floor walkway, both seen here
The hotel had only been in operation for approximately one year at the time of the walkways
collapse, and the ensuing investigation of the accident revealed some unsettling facts:
 During January and February, 1979, the design of the hanger rod connections was changed in a
series of events and disputed communications between the fabricator (Havens Steel Company)
and the engineering design team (G.C.E. International, Inc., a professional engineering firm).
The fabricator changed the design from a one-rod to a two-rod system to simplify the
assembly task, doubling the load on the connector, which ultimately resulted in the
walkways collapse. (Figure 3)
Figure 3. Original Design vs. Actual Construction
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The fabricator, in sworn testimony before the administrative judicial hearings after the accident,
claimed that his company (Havens) telephoned the engineering firm (G.C.E.) for change
approval. G.C.E. denied ever receiving such a call from Havens.2
On October 14, 1979 (more than one year before the walkways collapsed), while the hotel was
still under construction, more than 2700 square feet of the atrium roof collapsed because one of
the roof connections at the north end of the atrium failed.3 In testimony, G.C.E. stated that on
three separate occasions they requested on-site project representation during the construction
phase; however, these requests were not acted on by the owner (Crown Center Redevelopment
Corporation), due to additional costs of providing on-site inspection.4
Even as originally designed, the walkways were barely capable of holding up the expected load,
and would have failed to meet the requirements of the Kansas City Building Code.5
Due to evidence supplied at the Hearings, a number of principals involved lost their engineering
licenses, a number of firms went bankrupt, and many expensive legal suits were settled out of
court. The case serves as an excellent example of the importance of meeting professional
responsibilities, and what the consequences are for professionals who fail to meet those
responsibilities. This case is particularly serviceable for use in structural design, statics and
materials classes, although it is also useful as a general overview of consequences for professional
actions. The Hyatt Regency Walkways Collapse provides a vivid example of the importance of
accuracy and detail in engineering design and shop drawings (particularly regarding revisions), and
the costly consequences of negligence in this realm.
For purposes of this case study, we assume that the disputed telephone call was made by the
fabrication firm, and that the engineering firm did give verbal approval for the fatal design change.
Students are, however, encouraged to view the case reversing these assumptions.
Guidelines For Presentation
1) Read student handout for a detailed description of the case.
2) At the class preceding case discussion, distribute student handouts: The Kansas City Hyatt
Regency Walkways Collapse, which includes literature on negligence and the professional
"debate" over responsibility for design, and an annotated bibliography. Have students come to the
follow-up discussion class prepared to address the Kansas City Hyatt Regency Walkways Collapse
in light of the ethical issues raised in the student handout.
3) Show Hyatt Regency Walkways Collapse segment of the "To Engineer is Human," video.
Discuss with students the five overheads:
1. The Hyatt Regency Walkways Collapse Cast of Characters
2. Hanger Rod Details Original Design and As Built
3. Chronology of the Hyatt Regency Walkways Collapse (four pages)
4. ASME Code of Ethics of Engineers; and
5. IEEE Code of Ethics. Ask students some of the following questions:
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Who is ultimately responsible for the fatal design flaw? Why?

Does the disputed telephone call matter to the outcome of the case? Why or why not?
What is the responsibility of a licensed professional engineer who affixes his/her seal to
fabrication drawings?
In terms of meeting building codes, what are the responsibilities of the engineer? The
fabricator? The owner?
What measures can professional societies take to ensure that catastrophes such as the Hyatt
Regency Walkways Collapse do not occur?
Do you agree with the findings that the principal engineers involved should have been subject
to discipline for gross negligence in the practice of engineering? Should they have lost their
licenses, temporarily or permanently?
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Was it fair that G.C.E., as a company, was held liable for gross negligence and engineering
incompetence? Why or why not?
4) End the discussion with Overhead 6), Hyatt Regency Walkways Collapse: Ethical Issues of the
Case. Discuss the ethical questions raised by the case: what are the professional responsibilities of
the engineers, fabricators, and hotel contractors? How can professionals protect themselves, and
the public, from the gross negligence of an incompetent few? What are the implications of this
case in terms of state-by-state licensing procedures?
Recommended Overheads For Use In Classroom Discussion
1) The Hyatt Regency Walkways Collapse Cast of Characters
2) Hanger Rod Details Original Design and As Built
3) Chronology of the Hyatt Regency Walkways Collapse
4) ASME Code of Ethics of Engineers
5) IEEE Code of Ethics
6) Hyatt Regency Walkways Collapse: Ethical Issues Of The Case
Notes
1. Missouri Board for Architects, Professional Engineers and Land Surveyors vs. Daniel M.
Duncan, Jack D. Gillum and G.C.E. International, Inc., before the Administrative Hearing
Commission, State of Missouri, Case No. AR840239, Statement of the Case, Findings of Fact,
Conclusions of Law and Decision rendered by Judge James B. Deutsch, November 14, 1985,
2.
3.
4.
5.
pp. 54-63. Case No. AR840239 hereinafter referred to as Administrative Hearing
Commission.
Administrative Hearing Commission, pp. 63-66.
Administrative Hearing Commission, p. 384.
Administrative Hearing Commission, pp. 12-13.
Administrative Hearing Commission, pp. 423-425.
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Hyatt Regency Walkways Collapse Overheads
1. The Hyatt Regency Walkways Collapse Cast of Characters
2. Hanger Rod Details Original Design and As Built
3. Chronology of the Hyatt Regency Walkways Collapse (4 pages)
4. ASME Code of Ethics of Engineers
5. IEEE Code of Ethics
6. Hyatt Regency Walkways Collapse: Ethical Issues Of The Case
The Hyatt Regency Walkways Collapse Cast Of Characters
In 1976, as owner, Crown Center Redevelopment Corporation - commenced a project to
design and build a Hyatt Regency Hotel in Kansas City, Missouri, and on April 4, 1978, Crown
entered into a standard contract with G.C.E. International, Inc. Professional Consulting Firm of
Structural Engineers (1980 formerly called Jack D. Gillum & Associates, Ltd. changed name to
G.C.E. May 5, 1983)
Principals
 Jack D. Gillum P.E., structural engineering state licensed since February 26, 1968
 Daniel M. Duncan P.E., structural engineering state licensed since February 27, 1979
 PBNDML Architects, Planners, Inc. Architect.
G.C.E. agreed to provide, "all structural engineering services for a 750-room hotel projected
located at 2345 McGee Street, Kansas City, Missouri."
On or about December 19, 1978, Eldridge Construction Company, the general contractor on the
Hyatt project, entered into a subcontract with Havens Steel Company Professional Fabricator who
agreed to fabricate and erect the atrium steel for the Hyatt project.
Chronology Of The Hyatt Regency Walkways Collapse
Early 1976: Crown Center Redevelopment Corporation (owner) commences project to design and
build a Hyatt Regency Hotel in Kansas City, Missouri.
July 1976: Gillum-Colaco, Inc. (G.C.E. International, Inc., 1983), a Texas corporation, selected as
the consulting structural engineer for the Hyatt project.
July 1976- Hyatt project in schematic design development.
Summer 1977: G.C.E. assisted owner and architect (PBNDML Architects, Planners, Inc.) with
developing various plans for hotel project, and decided on basic design.
Late 1977- Bid set of structural drawings and specifications
Early 1978: Project prepared, using standard Kansas City, Missouri, Building Codes.
April 4, 1978: Actual contract entered into by G.C.E. and the architect, PBNDML Architects,
Planners, Inc. G.C.E. agreed to provide "all structural engineering services for a 750-room hotel
project located at 2345 McGee Street, Kansas City, Missouri."
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Spring 1978: Construction on hotel begins.
August 28, 1978: Specifications on project issued for construction, based on the American Institute
of Steel Construction (AISC) standards used by fabricators.
December 1978: Eldridge Construction Company, general contractor on the Hyatt project, enters
into subcontract with Havens Steel Company. Havens agrees to fabricate and erect the atrium steel
for the Hyatt project.
January 1979: Events and communications between G.C.E. and Havens.
February 1979: Havens makes design change from a single to a double hanger rod box beam
connection for use at the fourth floor walkways. Telephone calls disputed; however, because of
alleged communications between engineer and fabricator, Shop Drawing 30 and Erection Drawing
E3 are changed.
February 1979: G.C.E. receives 42 shop drawings (including Shop Drawing 30 and Erection
Drawing E-3) on February 16, and returns them to Havens stamped with engineering review stamp
approval on February 26.
October 14, 1979: Part of the atrium roof collapses while the hotel is under construction.
Inspection team called in, whose contract dealt primarily with the investigation of the cause of the
roof collapse and created no obligation to check any engineering or design work beyond the scope
of their investigation and contract.
October 16, 1979: Owner retains an independent engineering firm, Seiden-Page, to investigate the
cause of the atrium roof collapse.
October 20, 1979: Gillum writes owner, stating he is undertaking both an atrium collapse
investigation as well as a thorough design check of all the members comprising the atrium roof.
October- Reports and meetings from engineer to clients
November 1979: owner/architect assures clients of overall safety of the entire atrium.
July 1980: Construction of hotel complete, and the Kansas City Hyatt Regency Hotel opens for
business.
July 17, 1981: Connections supporting the rods from the ceiling that held up the 2nd and 4th floor
walkways across the atrium of the Hyatt Regency Hotel collapse, killing 114 and injuring in excess
of 200 others.
February 3, 1984: Missouri Board of Architects, Professional Engineers and Land Surveyors files
complaint against Daniel M. Duncan, Jack D. Gillum and G.C.E. International Inc., charging gross
negligence, incompetence, misconduct and unprofessional conduct in the practice of engineering in
connection with their performance of engineering services in the design and construction of the
Hyatt Regency Hotel in Kansas City, Missouri.
November, 1984: Duncan, Gillum, and G.C.E. International, Inc. found guilty of gross negligence,
misconduct and unprofessional conduct in the practice of engineering. Subsequently, Duncan and
Gillum lost their licenses to practice engineering in the State of Missouri, and G.C.E. had its
certificate of authority as an engineering firm revoked. American Society of Civil Engineering
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(ASCE) adopts report that states structural engineers have full responsibility for design projects.
Duncan and Gillum now practicing engineers in states other than Missouri.
ASME Code Of Ethics Of Engineers
The Fundamental Principles
Engineers uphold and advance the integrity, honor, and dignity of the Engineering profession
by:
I. using their knowledge and skill for the enhancement of human welfare;
II. being honest and impartial, and serving with fidelity the public, their employers and
clients; and
III. striving to increase the competence and prestige of the engineering profession.
The Fundamental Canons
1. Engineers shall hold paramount the safety, health and welfare of the public in the performance
of their professional duties.
2. Engineers shall perform services only in areas of their competence.
3. Engineers shall continue their professional development throughout their careers and shall
provide opportunities for the professional development of those engineers under their
supervision.
4. Engineers shall act in professional matters for each employer or client as faithful agents or
trustees, and shall avoid conflicts of interest.
5. Engineers shall build their professional reputation on the merit of their services and shall not
compete unfairly with others.
6. Engineers shall associate only with reputable persons or organizations.
7. Engineers shall issue public statements only in an objective and truthful manner.
Board, Professional Practice and Ethics
IEEE Code Of Ethics (Revised October 1990)
We, the members of the IEEE, in recognition of the importance of our technologies in affecting the
quality of life throughout the world, and in accepting a personal obligation to our profession, its
members and the communities we serve, do hereby commit ourselves to the highest ethical and
professional conduct and agree:
1. to accept responsibility in making engineering decisions consistent with the safety, health, and
welfare of the public, and to disclose promptly factors that might endanger the public or the
environment;
2. to avoid real or perceived conflicts of interest whenever possible, and to disclose them to
affected parties when they do exist;
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3. to be honest and realistic in stating claims or estimates based on available data;
4. to reject bribery in all its forms;
5. to improve the understanding of technology, its appropriate application, and potential
consequences;
6. to maintain and improve our technical competence and to undertake technological tasks for
others only if qualified by training or experience, or after full disclosure of pertinent
limitations;
7. to seek, accept, and offer honest criticism of technical work, to acknowledge and correct errors,
and to credit properly the contributions of others;
8. to treat fairly all persons regardless of such factors as race, religion, gender, disability, age, or
national origin;
9. to avoid injuring others, their property, reputation, or employment by false or malicious action;
10. to assist colleagues and coworkers in their professional development and to support them in
following this code of ethics.
Hyatt Regency Walkways Collapse: Ethical Issues Of The Case
1. Who is ultimately responsible for checking the safety of final designs as depicted in shop
drawings?
2. In terms of meeting building codes, what are the responsibilities of the engineer? The
fabricator? The owner?
3. What measures can professional societies take to ensure catastrophes like the Hyatt Regency
Walkways Collapse do not occur?
Case Studies # 2-The Kansas City Hyatt Regency Walkways Collapse
~Negligence And The Professional "Debate" Over Responsibility For Design
Discussion Answer Sheets
Questions for Class Discussion
4. Who is ultimately responsible for checking the safety of final designs as depicted in shop
drawings?
Case Studies # 2-The Kansas City Hyatt Regency Walkways Collapse
~Negligence And The Professional "Debate" Over Responsibility For Design
Synopsis
On July 17, 1981, the Hyatt Regency Hotel in Kansas City, Missouri, held a videotaped tea-dance
party in their atrium lobby. With many party-goers standing and dancing on the suspended
walkways, connections supporting the ceiling rods that held up the second and fourth-floor
walkways across the atrium failed, and both walkways collapsed onto the crowded first-floor
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atrium below. The fourth-floor walkway collapsed onto the second-floor walkway, while the offset
third-floor walkway remained intact. As the United States' most devastating structural failure, in
terms of loss of life and injuries, the Kansas City Hyatt Regency walkways collapse left 114 dead
and in excess of 200 injured. In addition, millions of dollars in costs resulted from the collapse,
and thousands of lives were adversely affected.
The hotel had only been in operation for approximately one year at the time of the walkways
collapse, and the ensuing investigation of the accident revealed some unsettling facts.
First, during January and February, 1979, over a year before the collapse, the design of the
walkway hanger rod connections was changed in a series of events and communications (or
disputed miscommunications) between the fabricator (Havens Steel Company) and the engineering
design team (G.C.E. International, Inc., a professional engineering firm). The fabricator changed
the design from a one-rod to a two-rod system to simplify the assembly task, doubling the load on
the connector, which ultimately resulted in the walkways collapse. (Figure 1)
Figure 1. Original Design vs. Actual Construction
Second, the fabricator, in sworn testimony before the administrative judicial hearings after the
accident, claimed that his company (Havens) telephoned the engineering firm (G.C.E.) for change
approval. G.C.E. denied ever receiving such a call from Havens.
Third, on October 14, 1979, while the hotel was still under construction, more than 2700 square
feet of the atrium roof collapsed because one of the roof connections at the north end of the atrium
failed. In testimony, G.C.E. stated that on three separate occasions they requested on-site project
representation to check all fabrication during the construction phase; however, these requests were
not acted on by the owner (Crown Center Redevelopment Corporation), due to additional costs of
providing on-site inspection.
Fourth, even as originally designed, the walkways were barely capable of holding up the expected
load, and would have failed to meet the requirements of the Kansas City Building Code.
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Individuals Involved In The Hyatt Regency Case
Several key players are involved in the case:
In 1976, as owner, Crown Center Redevelopment Corporation commenced a project to design
and build a Hyatt Regency Hotel in Kansas City, Missouri, and on April 4, 1978 entered into a
standard contract with G.C.E. International, Inc. Professional Consulting Firm of Structural
Engineers (1980 formerly called Jack D. Gillum & Associates, Ltd. changed name to G.C.E. May
5, 1983) Principals Jack D. Gillum P.E., structural engineering state licensed since February 26,
1968 Daniel M. Duncan P.E., structural engineering state licensed since February 27, 1979 and
PBNDML Architects, Planners, Inc. Architect. G.C.E. agreed to provide, "all structural
engineering services for a 750-room hotel projected located at 2345 McGee Street, Kansas City,
Missouri. On or about December 19, 1978, Eldridge Construction Company, the general contractor
on the Hyatt project, entered into a subcontract with Havens Steel Company fabricator who
agreed to fabricate and erect the atrium steel for the Hyatt project.
Structural Failure During the Atrium Tea Dance
In 1976, Crown Center Redevelopment Corporation initiated a project for designing and building a
Hyatt Regency Hotel in Kansas City Missouri. In July of 1976, Gillum-Colaco, Inc., a Texas
corporation, was selected as the consulting structural engineer for the project. A schematic design
development phase for the project was undertaken from July 1976 through the summer of 1977.
During that time, Jack D. Gillum (the supervisor of the professional engineering activities of
Gillum-Colaco, Inc.) and Daniel M. Duncan (working under the direct supervision of Gillum, the
engineer responsible for the actual structural engineering work on the Hyatt project) assisted
Crown Center Redevelopment Corporation (the owner) and PBNDML Architects, Planners, Inc.
(the architect on the project) in developing plans for the hotel project and deciding on its basic
design. A bid set of structural drawings and specifications for the project were prepared in late
1977 and early 1978, and construction began on the hotel in the spring of 1978. The specifications
on the project were issued for construction on August 28, 1978.6
On April 4, 1978, the actual written contract was entered into by Gillum-Colaco, Inc. and
PBNDML Architects, Planners, Inc. The contract was standard in nature, and Gillum-Colaco, Inc.
agreed to provide all the structural engineering services for the Hyatt Regency project. The firm
Gillum-Colaco, Inc. did not actually perform the structural engineering services on the project;
instead, they subcontracted the responsibility for performing all of the structural engineering
services for the Hyatt Regency Hotel project to their subsidiary firm, Jack D. Gillum & Associates,
Ltd. (hereinafter referenced as G.C.E.).7 According to the specifications for the project, no work
could start until the shop drawings for the work had been approved by the structural engineer.8
Three teams, with particular roles to play in the construction system employed in building the
Hyatt Regency Hotel, were contracted for the project: PBNDML and G.C.E. made up the "design
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team," and were authorized to control the entire project on behalf of the owner; Eldridge
Construction Co., as the "construction team," was responsible for general contracting; and the
"inspection team," made up of two inspecting agencies (H&R Inspection and General Testing), a
quality control official, a construction manager, and an investigating engineer (Seiden and Page).
On December 19, 1978, Eldridge Construction Company, as general contractor, entered into a
subcontract with Havens Steel Company, who agreed to fabricate and erect the atrium steel for the
Hyatt project.
G.C.E. was responsible for preparing structural engineering drawings for the Hyatt project: three
walkways spanning the atrium area of the hotel. Wide flange beams with 16-inch depths (W16x26)
were used along either side of the walkway and hung from a box beam (made from two MC8x8.5
rectangular channels, welded toe-to-toe). A clip angle welded to the top of the box beam connected
these beams by bolts to the W section. This joint carried virtually no moment, and therefore was
modeled as a hinge. One end of the walkway was welded to a fixed plate and would be a fixed
support, but for simplicity, it could be modeled as a hinge. This only makes a difference on the
hanger rod nearest this support (it would carry less load than the others and would not govern
design). The other end of the walkway support was a sliding bearing modeled by a roller. The
original design for the hanger rod connection to the fourth floor walkway was a continuous rod
through both walkway box beams (Figure 1).
Events and disputed communications between G.C.E. engineers and Havens resulted in a
design change from a single to a double hanger rod box beam connection for use at the
fourth floor walkways. The fabricator requested this change to avoid threading the entire rod.
They made the change, and the contract's Shop Drawing 30 and Erection Drawing E-3 were
changed (Figure 1 shows the hanger rod as built).
On February 16, 1979, G.C.E. received 42 shop drawings (including the revised Shop Drawing 30
and Erection Drawing E-3). On February 26, 1979, G.C.E. returned the drawings to Havens,
stamped with Gillum's engineering review seal, authorizing construction. The fabricator (Havens)
built the walkways in compliance with the directions contained in the structural drawings, as
interpreted by the shop drawings, with regard to these hangers. In addition, Havens followed the
American Institute of Steel Construction (AISC) guidelines and standards for the actual design of
steel-to-steel connections by steel fabricators.
As a precedent for the Hyatt case, the Guide to Investigation of Structural Failure's Section 4.5,
"Failure Causes Classified by Connection Type," states that:
Overall collapses resulting from connection failures have occurred only in structures with few or
no redundancies. Where low strength connections have been repeated, the failure of one has lead to
failure of neighboring connections and a progressive collapse has occurred. The primary causes of
connection failures are:
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1. Improper design due to lack of consideration of all forces acting on a connection, especially
those associated with volume changes.
2. Improper design utilizing abrupt section changes resulting in stress concentrations.
3. Insufficient provisions for rotation and movement.
4. Improper preparation of mating surfaces and installation of connections.
5. Degradation of materials in a connection.
6. Lack of consideration of large residual stresses resulting from manufacture or fabrication.
On October 14, 1979, part of the atrium roof collapsed while the hotel was under construction. As
a result, the owner called in the inspection team. The inspection team's contract dealt primarily
with the investigation of the cause of the roof collapse and created no obligation to check any
engineering or design work beyond the scope of their investigation and contract. In addition to the
inspection team, the owner retained, on October 16, 1979, an independent engineering firm,
Seiden-Page, to investigate the cause of the atrium roof collapse. On October 20, 1979, G.C.E.'s
Gillum wrote the owner, stating that he was undertaking both an atrium collapse investigation as
well as a thorough design check of all the members comprising the atrium roof. G.C.E. promised
to check all steel connections in the structures, not just those found in the roof.
From October-November, 1979, various reports were sent from G.C.E. to the owner and architect,
assuring the overall safety of the entire atrium. In addition to the reports, meetings were held
between the owner, architect and G.C.E.
In July of 1980, the construction was complete, and the Kansas City Hyatt Regency Hotel was
opened for business.
Just one year later, on July 17, 1981, the box beams resting on the supporting rod nuts and washers
were deformed, so that the box beam resting on the nuts and washers on the rods could no longer
hold up the load. The box beams (and walkways) separated from the ceiling rods and the fourth
and second floor walkways across the atrium of the Hyatt Regency Hotel collapsed, killing 114
and injuring in excess of 200 others.
One investigation report gave the following summary:
The Hyatt Regency consists of three main sections: a 40-story tower section, a function block, and
a connecting atrium. The atrium is a large open area, approximately 117 ft (36 m) by 145 ft (44 m)
in plan and 50 ft (15 m) high. Three suspended walkways spanned the atrium at the second, third
and fourth floor levels [see Figure 3 on following page]. These walkways connected the tower
section and the function block. The third floor walkway was independently suspended from the
atrium roof trusses while the second floor walkway was suspended from the fourth floor walkway,
which in turn was suspended from the roof framing.
In the collapse, the second and fourth floor walkways fell to the atrium first floor with the fourth
floor walkway coming to rest on top of the second. Most of those killed or injured were either on
the atrium first floor level or on the second floor walkway. The third floor walkway was not
involved in the collapse.
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Following the accident investigations, on February 3, 1984, the Missouri Board of Architects,
Professional Engineers and Land Surveyors filed a complaint against Daniel M. Duncan, Jack D.
Gillum, and G.C.E. International, Inc., charging gross negligence, incompetence, misconduct and
unprofessional conduct in the practice of engineering in connection with their performance of
engineering services in the design and construction of the Hyatt Regency Hotel. The NBS report
noted that:
The hanger rod detail actually used in the construction of the second and fourth floor
walkways is a departure from the detail shown on the contract drawings. In the original
arrangement each hanger rod was to be continuous from the second floor walkway to the
hanger rod bracket attached to the atrium roof framing. The design load to be transferred to
each hanger rod at the second floor walkway would have been 20.3 kips (90 kN). An essentially
identical load would have been transferred to each hanger rod at the fourth floor walkway. Thus
the design load acting on the upper portion of a continuous hanger rod would have been twice that
acting on the lower portion, but the required design load for the box beam hanger rod connections
would have been the same for both walkways (20.3 kips (90 kN)).
The hanger rod configuration actually used consisted of two hanger rods: the fourth floor to ceiling
hanger rod segment as originally detailed on the second to fourth floor segment which was offset 4
in. (102 mm) inward along the axis of the box beam. With this modification the design load to
be transferred by each second floor box beam-hanger rod connection was unchanged, as
were the loads in the upper and lower hanger rod segments. However, the load to be
transferred from the fourth floor box beam to the upper hanger rod under this arrangement
was essentially doubled, thus compounding an already critical condition. The design load for a
fourth floor box beam-hanger rod connection would be 40.7 kips (181 kN) for this configuration.
Had this change in hanger rod detail not been made, the ultimate capacity of the box beam-hanger
rod connection still would have been far short of that expected of a connection designed in
accordance with the Kansas City Building Code, which is based on the AISC Specification. In
terms of ultimate load capacity of the connection, the minimum value should have been 1.67 times
20.3, or 33.9 kips (151 kN). Based on test results the mean ultimate capacity of a single-rod
connection is approximately 20.5 kips (91 kN), depending on the weld area. Thus the ultimate
capacity actually available using the original connection detail would have been approximately
60% of that expected of a connection designed in accordance with AISC Specifications.12
During the 26-week administrative law trial that ensued, G.C.E. representatives denied ever
receiving the call about the design change. Yet, Gillum affixed his seal of approval to the revised
engineering design drawings.
Results of the hearing concluded that G.C.E., in preparation of their structural detail drawings,
"depicting the box beam hanger rod connection for the Hyatt atrium walkways, failed to conform
to acceptable engineering practice. [This is based] upon evidence of a number of mistakes, errors,
omissions and inadequacies contained on this section detail itself and of [G.C.E.'s] alleged failure
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to conform to the accepted custom and practice of engineering for proper communication of the
engineer's design intent."13 Evidence showed that neither due care during the design phase, nor
appropriate investigations following the atrium roof collapse were undertaken by G.C.E. In
addition, G.C.E. was found responsible for the change from a one-rod to a two-rod system. Further,
it was found that even if Havens failed to review the shop drawings or to specifically note the box
beam hanger rod connections, the engineers were still responsible for the final check. Evidence
showed that G.C.E. engineers did not "spot check" the connection or the atrium roof collapse, and
that they placed too much reliance on Havens.
Due to evidence supplied at the Hearings, a number of principals involved lost their engineering
licenses, a number of firms went bankrupt, and many expensive legal suits were settled out of
court. In November, 1984, Duncan, Gillum, and G.C.E. International, Inc. were found guilty of
gross negligence, misconduct and unprofessional conduct in the practice of engineering.
Subsequently, Duncan and Gillum lost their licenses to practice engineering in the State of
Missouri (and later, Texas), and G.C.E. had its certificate of authority as an engineering firm
revoked.
As a result of the Hyatt Regency Walkways Collapse, the American Society of Civil Engineering
(ASCE) adopted a report that states structural engineers have full responsibility for design projects.
Both Duncan and Gillum are now practicing engineers in states other than Missouri and Texas.
The responsibility for and obligation to design steel-to-steel connections in construction lies at the
heart of the Hyatt Regency Hotel project controversy. To understand the issues of negligence and
the engineer's design responsibility, we must examine some key elements associated with
professional obligations to protect the public. This will be discussed in class from three
perspectives: the implicit social contract between engineers and society; the issue of public risk
and informed consent; and negligence and codes of ethics of professional societies.
Ethical Issues Of The Case - Points For Discussion
This case centers on the question of who is responsible for a design failure. As an ethical issue,
 Who is ultimately responsible for checking the safety of final designs as depicted in shop
drawings?
When we take the implicit social contract between engineers and society, the issue of public risk
and informed consent, and codes of ethics of professional societies into account, it seems clear that
the engineer must assume this responsibility when any change in design involving public safety
carries a licensed engineer's seal. Yet,
 In terms of meeting building codes, what are the responsibilities of the engineer? The
fabricator? The owner?
If we assume the engineer in the Hyatt case received the fabricator's telephone call requesting a
verbal approval of the design change for simplifying assembly, what would make him approve
such an untenable change? Some possible reasons include:
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saving time;

saving money;
 avoiding a call for re-analysis, thereby raising the issue of a request to recheck all connector
designs following the previous year's atrium roof collapse;
 following his immediate supervisor's orders;
 looking good professionally by simplifying the design;
 misunderstanding the consequences of his actions; or
 any combination of the above.
These reasons do not, however, fall within acceptable standards of engineering professional
conduct. Instead, they pave the way for legitimate charges of negligence, incompetence,
misconduct and unprofessional conduct in the practice of engineering. When the engineer's actions
are compared to professional responsibilities cited in the engineering codes of ethics, an abrogation
of professional responsibilities by the engineer in charge is clearly demonstrated. But what of the
owner, or the fabricator?
What if the call was not made? While responsibility rests with the fabricator for violating building
codes, would the engineers involved in the case be off the hook? Why or why not?
The Hyatt Regency walkways collapse has resulted in a nationwide reexamination of building
codes. In addition, professional codes on structural construction management practices are
changing in significant ways.14 Finally, what is your assessment of this case, based on the
following questions:
 What measures can professional societies take to ensure catastrophes like the Hyatt Regency

Walkways Collapse do not occur?
Should Gillum and Duncan be allowed to practice engineering in other states? Why or why not?
What is the engineering society's responsibility in this realm?
Annotated Bibliography
Davis, Michael, "Thinking Like An Engineer: The Place of a Code of Ethics in the Practice of a
Profession," Philosophy & Public Affairs, Vol. 20, No. 2, Spring 1991, pp. 150-167. (see also,
"Explaining Wrongdoing," Journal of Social Philosophy, Vol. 20, Numbers 1&2, Spring/Fall
1989, pp. 74-90.
In these lucid essays, Davis argues that "a code of professional ethics is central to advising
individual engineers how to conduct themselves, to judging their conduct, and ultimately to
understanding engineering as a profession." Using the now infamous Challenger disaster as his
model, Davis discusses both the evolution of engineering ethics as well as why engineers should
obey their professional codes of ethics, from both a pragmatic and ethically-responsible point of
view. Essential reading for any graduating engineering student.
Engineering News Report.
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Throughout the hearings, Engineering News Report, published by the National Society of
Professional Engineers (NSPE), kept vigilant watch over the case. Of particular interest are their
following articles:
 "Hyatt Walkway Design Switched," July 30, 1981.
 "Hyatt Hearing Traces Design Change," July 26, 1984.
 "Difference of Opinion: Hyatt Structural Engineer Gillum Disputes NBS Collapse Report,"
September 6, 1984.
 "Weld Aided Collapse, Witness Says," September 13, 1984.
 "Judge Bars Hyatt Tests," September 20, 1984.
 "Hyatt Engineers Found Guilty of Negligence," November 21, 1985.
 "Hyatt Ruling Rocks Engineers," November 28, 1985.

"Construction Rescuers Sue," August 7, 1986.
Glickman, Theodore S., and Michael Gough (eds.), Readings in Risk, Washington, D.C.:
Resources for the Future, 1990.
This is an excellent collection of essays on managing technology-induced risk. As a starting-off
point, of particular worth to the engineers are the essays: "Probing the Question of
Technology-Induced Risk" and "Choosing and Managing Technology-Induced Risk," by M.
Granger Morgan; "Defining Risk," by Baruch Fischhoff, Stephen R. Watson, and Chris Hope;
"Risk Analysis: Understanding 'How Safe is Safe Enough?'," by Stephen L. Derby and Ralph L.
Keeney; "Social Benefit Versus Technological Risk," by Chauncey Starr; and "The Application of
Probabilistic Risk Assessment Techniques to Energy Technologies," by Norman C. Rasmussen.
Gibble, Kenneth (ed.), Management Lessons from Engineering Failures, Proceedings of a
symposium sponsored by the Engineering Management Division of the American Society of Civil
Engineers in conjunction with the ASCE Convention in Boston, October 28, 1986, New York:
American Society of Civil Engineers, 1986.
This short work examines a variety of engineering failures, including those involving individual
planning, and project failures. In particular see Irvin M. Fogel's essay, "Avoiding 'Failures' Caused
by Lack of Management," and Gerald W. Farquhar's "Lessons to be Learned in the Management of
Change Orders in Shop Drawings," both excellent illustrations for use with the Hyatt case.
Hall, John C., "Acts and Omissions," The Philosophical Quarterly, Vol. 39, No. 157, October
1989, pp. 399-408.
This article is a discussion of the legal and ethical ramifications of professional choices and
activities, both active and passive.
"Hyatt Notebook: Parts I and II," Kansas City, October 1984 and November 1984.
These are two articles written by a Kansas City television reporter for the local magazine, Kansas
City, detailing highlights from the 26-week Hyatt Regency Walkways Collapse hearings.
Janney, Jack R. (ed.), Guide to Investigation of Structural Failures, prepared for the American
Society of Civil Engineers' Research Council on Performance of Structures, sponsored by the
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Federal
Highway
Administration,
U.S.
Department
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of
Transportation,
Contract
No.
DOTFH118843, 1979.
This short volume gives an excellent overview of structural failure investigation procedures, and
discusses failure causes by project type, structural type, and material, connection and foundation
type. In addition, discussions on field operations, project management, and data analysis and
reports are offered. Of particular interest to those studying the Hyatt case are sections 4.5-4.7,
"Failure Causes Classified by Connection Type," and "Steel to Steel Connections."
Martin, Mike W. and Roland Schinzinger, Ethics in Engineering (2nd ed.), New York:
McGraw-Hill Book Company, 1989.
An excellent text-book treatment of ethical issues in engineering. Of particular interest to this case
is Part Two, "The Experimental Nature of Engineering," and Part Three, "Engineers, Management
and Organizations."
McK Norrie, Kenneth, "Reasonable: The Keystone of Negligence," Journal of Medical Ethics,
Vol. 13, No. 2, June 1987, pp. 92-94.
This article is a brief discussion of legal liability for professional actions. "The more knowledge,
skill and experience a person has, the higher standard the law subjects that person to" (p. 92).
PDF version: Missouri Board for Architects, Professional Engineers and Land Surveyors vs.
Daniel M. Duncan, Jack D. Gillum and G.C.E. International, Inc., before the Administrative
Hearing Commission, State of Missouri, Case No. AR840239, Statement of the Case, Findings
of Fact, Conclusions of Law and Decision rendered by Judge James B. Deutsch, November 14,
1985, 442 pp. Note this is a BIG file - 20 Mb!
Word version: Missouri Board for Architects, Professional Engineers and Land Surveyors vs.
Daniel M. Duncan, Jack D. Gillum and G.C.E. International, Inc., before the Administrative
Hearing Commission, State of Missouri, Case No. AR840239, Statement of the Case, Findings
of Fact, Conclusions of Law and Decision rendered by Judge James B. Deutsch, November 14,
1985, 442 pp. This has been changed to Word format, without any checking. Many errors are
found when the scanner attempted to transcribe the pdf file to Word, but no one has found the time
to correct the conversion
This volume contains the findings, conclusions of law and the final decision of the Hyatt Regency
Walkways Collapse case, as rendered by Judge James B. Deutsch. The volume contains both the
findings of the case and an excellent general discussion of responsibilities of the professional
engineer.
Pfrang, Edward O. and Richard Marshall, "Collapse of the Kansas City Hyatt Regency
Walkways," Civil Engineering-ASCE, July 1982, pp. 65-68.
Official findings of the failure investigation conducted by the National Bureau of Standards, U.S.
Department of Commerce. Among its conclusions was this: "Even if the now-notorious design
shift in the hanger rod details had not been made, the entire design of all three walkways, including
the one which did not collapse, was a significant violation of the Kansas City Building Code."
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Case Studies # 3-921 Earthquake in Taiwan and 2010 Haiti Earthquake
Introduction To The Cases
(1) 921 Earthquake in Taiwan:
The 921 earthquake, also known as the 1999 Jiji earthquake or simply 921, was a magnitude 7.6
earthquake which occurred at 1:47 local time (17:47 UTC) on September 21, 1999 in Jiji, Nantou
County, Taiwan. 2,416 people were killed, over 11,000 seriously injured, and NT$300bn worth of
damage was done. It was the second-deadliest quake in recorded history in Taiwan, after the 1935
Hsinchu-Taichung earthquake.
Rescue groups from around the world joined local relief workers and the ROC military in digging
out survivors, clearing rubble, restoring essential services and distributing food and other aid to the
more than 100,000 people made homeless by the quake. The disaster, dubbed the "Quake of the
Century" by local media, had a profound effect on the economy of the island and the
consciousness of the people, and dissatisfaction with government's performance in reacting to it
was said by some commentators to be a factor in the unseating of the ruling Kuomintang party in
the 2000 Presidential Election.
Figure 1. Earthquake Damage in Buildings, September 21, 1999, Taiwan
(2) 2010 Haiti Earthquake:
The 2010 Haiti earthquake was a catastrophic magnitude 7.0 Mw earthquake with the epicenter
near Léogane, approximately 25 kilometres (16 mi) west of Port-au-Prince, the capital of Haiti,
striking at 16:53:10 local time (21:53:10 UTC) on Tuesday, 12 January 2010. The earthquake
occurred at a depth of 13 kilometres (8.1 mi). The United States Geological Survey recorded a
series of at least 33 aftershocks, fourteen of them between magnitudes 5.0 and 5.9. The
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International Red Cross estimated that about three million people were affected by the quake, and
the Haitian Interior Minister believes that up to 200,000 have died as a result of the disaster,
exceeding earlier Red Cross estimates of 45,000–50,000. Several prominent public figures are
among the dead.
The earthquake caused major damage to Port-au-Prince. Most major landmarks were significantly
damaged or destroyed, including the Presidential Palace (President René Préval survived), the
National Assembly building, the Port-au-Prince Cathedral, and the main jail. To compound the
tragedy, most hospitals in the area were destroyed. The United Nations (UN) reported that the
headquarters of the United Nations Stabilization Mission in Haiti (MINUSTAH), located in the
capital, had collapsed and that the Mission's Chief, Hédi Annabi, his deputy, Luiz Carlos da Costa,
and the acting police commissioner were confirmed dead. Elisabeth Byrs of the UN called it the
worst disaster the United Nations has experienced because the organizational structures of the UN
in Haiti and the Haitian government were destroyed.
Figure 2. Downtown Port au Prince After Earthquake
Background-Basics of Earthquake Resistant Design
(1) Lateral Load Resisting Systems
When 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 resisting system. These
structural components usually include:

shear walls
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braced frames
moment resisting frames

diaphragms

horizontal trusses
Of course, a building always possesses floors and a roof. But the earthquake resistant
characteristics of these basic elements is highly variable. Not only that, the building's horizontal
elements 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. For
instance, some buildings such as a warehouse or a parking garage must have a large open floor
space--which means that roof and floors of such structures will not be provided with as much
vertical 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 of earthquake
resistance, building cost, building use, and architectural design.
Diaphragms
Figure 3
Diaphragms are horizontal resistance elements, generally floors and roofs, that transfer the lateral
forces between the vertical resistance elements (shear walls or frames). Basically, a diaphragm acts
as a horizontal I-beam. That is, the diaphragm itself acts as the web of the beam and its edges act
as flanges. (See figure 3)
Shear Walls
Shear 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 in which the
fibers within the wall try to slide past one another.
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Figure 4
When you build a house of cards, you design a shear wall structure, and you soon learn that
sufficient card "walls" must be placed at right angles to one another or the house will collapse. If
you were to connect your walls together with tape, it is easy to see that the strength of this house of
cards would significantly increase. This illustrates a very important point, in which the earthquake
resistance of any building is highly dependent upon the connections joining the building's larger
structural members, such as walls, beams, columns and floor-slabs.
Shear walls, in particular, must be strong in themselves and also strongly connected to each 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. This movement is
resisted by the shear walls and the forces are transmitted back down to the foundation.
(2) Plan of Building
(i) Symmetry: The building as a whole or its various blocks should be kept symmetrical about
both the axes. Asymmetry leads to torsion during earthquakes and is dangerous, Fig 5. Symmetry
is also desirable in the placing and sizing of door and window openings, as far as possible.
(ii) Regularity: Simple rectangular shapes, Fig 6 (a) behave better in an earthquake than shapes
with many projections Fig 6 (b). Torsional effects of ground motion are pronounced in long
narrow rectangular blocks. Therefore, it is desirable to restrict the length of a block to three times
its width. If longer lengths are required two separate blocks with sufficient separation in between
should be provided, Fig 6 (c).
(iii) Separation of Blocks: Separation of a large building into several blocks may be required so
as to obtain symmetry and regularity of each block. For preventing hammering or pounding
damage between blocks a physical separation of 3 to 4 cm throughout the height above the plinth
level will be adequate as well as practical for upto 3 storeyed buildings, Fig 6 (c). The separation
section can be treated just like expansion joint or it may be filled or covered with a weak material
which would easily crush and crumble during earthquake shaking. Such separation may be
considered in larger buildings since it may not be convenient in small buildings.
(iv)Simplicity: Ornamentation invo1ving large cornices, vertical or horizontal cantilever
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projections, facia stones and the like are dangerous and undesirable from a seismic viewpoint.
Simplicity is the best approach. Where ornamentation is insisted upon, it must be reinforced with
steel, which should be properly embedded or tied into the main structure of the building.
Note: If designed, a seismic coefficient about 5 times the coefficient used for designing the main
structure should be used for cantilever ornamentation.
(v) Enclosed Area: A small building enclosure with properly interconnected walls acts like a rigid
box since the earthquake strength which long walls derive from transverse walls increases as their
length decreases. Therefore structurally it will be advisable to have separately enclosed rooms
rather than one long room, Fig 7. For unframed walls of thickness t and wall spacing of a, a ratio
of a/t = 40 should be the upper limit between the cross walls for mortars of cement sand 1:6 or
richer, and less for poor mortars. For larger panels or thinner walls, framing elements should be
introduced as shown at Fig 7(c).
(vi) Separate Buildings for Different Functions: In view of the difference in importance of
hospitals, schools, assembly halls, residences, communication and security buildings, etc., it may
be economical to plan separate blocks for different functions so as to affect economy in
strengthening costs.
Figure 5. Torsion of unsymmetrical plans
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© Assistant Prof. Y.F. Ko, P.E.
Figure 6. Plan of building blocks.
Figure 7. Enclosed area forming box units
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© Assistant Prof. Y.F. Ko, P.E.
(3) Structural and Constructional Detailings
Figure 8. Rebars/Reinforcements Detailing of RC Beams
Figure 9. Rebars/Reinforcements Detailing of RC Columns
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Summary
Seismic resistance can be accomplished by following the basic steps given below:
a. Choosing a good configuration
b. Making a satisfactory analysis (Static or dynamic)
c. Proportioning and detailing the members properly.
d. Constructing the building in accordance with the design project, under good supervision. (main
reasons for building collapse in Taiwan and Haiti!)
Questions for Class Discussion
6. What do you (the students) see as your future engineering professional responsibilities in
relation to both being loyal to management and protecting the public welfare?
7. Can you design better buildings to resist the huge earthquake? How do you achieve these goals
as a Professional Structural Engineer?
8. How do you prevent the construction workers from not following the structural drawings in
construction site? Can you propose a better supervision system on the job site? What can you
do if you find out that the construction workers didn’t follow the structural drawings in
construction site after the work was done?
Case Studies # 3-921 Earthquake in Taiwan and 2010 Haiti Earthquake
Discussion Answer Sheets
Questions for Class Discussion
9. What do you (the students) see as your future engineering professional responsibilities in
relation to both being loyal to management and protecting the public welfare?
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