On September 4, 2010, a 7.1 magnitude earthquake struck near Christchurch, New Zealand.


Ethics Case Study

On September 4, 2010, a 7.1 magnitude earthquake struck near Christchurch, New Zealand. Though the earthquake caused significant damage to buildings and other infrastructure, no direct fatalities resulted from the quake – due largely to the epicenter’s distance from the city and its occurrence in the early morning hours, when few people were away from their homes.

Tragically, some five months later, on February 22, 2011, Christchurch was hit by a strong aftershock, this time registering 6.3 in magnitude. Located significantly closer to the center of the city and hitting buildings that had already been weakened by the earlier quake, the aftershock exacted a more significant toll in terms of damage and lives lost.

Of the 185 individuals killed in the 2011 aftershock, more than 60% (115) were killed in the collapse of a single building – the CTV building, a six story structure that held the offices of the Canterbury Television station as well as a language school and other commercial tenants. Witnesses and survivors described the building’s collapse as sudden and quick, beginning with an initial twisting as the building shook, before concrete columns on the fifth floor exploded outward all at once. The firth floor’s disintegration triggered the lower floors to pancake one by one, while the sixth floor sank almost intact to the ground; the entire collapse is believed to have occurred within 20 seconds of the start of the quake.

The commission tasked with investigating the collapse focused much of its attention on two engineers involved in the project – the building’s design engineer and the principal of the firm that employed him. The committee learned that before his work on the CTV building in 1986, the design engineer had never designed a structure of more than two stories. In addition, the client had requested an asymmetrical design for his structure, with an elevator shaft in an offset core on the north wall of the building; this, too, was a type of design with which the engineer had no previous experience.

Under the New Zealand building code, engineers designing multistory structures were required to use computer analysis to measure earthquake loading on the structure. While the CTV building’s design engineer was unfamiliar with the software used for such tests, he nevertheless ran an analysis of his design and made several modification to his plans before reaching a result that appeared to show deflections within allowable limits.

Unfortunately, the design engineer was unaware of an important limitation in the software’s analysis. The program produced deflection data for a single point at the center of mass for each floor. But because of the CTV building’s eccentric design, a proper analysis required the structural engineer to determine the building’s center of rotation – somewhere other than the center of mass – and use that location to calculate deflections at the corners. Because of his failure to account for the structure’s shape, the engineer’s analysis projected that the design would produce far less floor movement during an earthquake than in fact was the case.

The result, as noted by the investigating commission, was a structure that was “under-engineered in a number of important respects.” Critical design flaws included inadequate shear reinforcement and concrete cover on the structural columns, inadequate design of the beam-to-column joints, and inadequate connections between the floor slab diaphragms and the building’s north wall complex. These flaws meant that the two elements designed to protect the building from seismic forces – the north wall complex and the coupled shear wall on the south – were unable to perform their intended function.

In response to the commission’s inquiry, both the engineer and his principal tried to shift some degree of blame for the failure to the other. The design engineer said that the principal’s frequent questions and other conduct had led him to believe the principal was reviewing his work. The design engineer stated “If I had thought I was doing it myself, I would have bailed right then.” The principal argued that the engineer had more than 10 years’ experience at the time of the assignment and occupied a senior position in the firm. The principal said the engineer had never raised any concerns about his competence, and he believed it was the engineer’s responsibility to seek assistance if he was having trouble with the design.

Ultimately, the commission ruled that the design engineer had been working “well beyond” his level of experience in designing the CTV building and that he should not have undertaken to design the structure without review by a more qualified professional. Likewise, it found the firm’s principal was aware of the design engineer’s lack of relevant experience and that he should not have permitted the engineer to perform the work without supervision or review.

As is frequently the case with catastrophic engineering failures, the events leading to the CTV building’s collapse were not confined to the design flaws, but rather included a long chain of contributory acts and missed opportunities that propelled the structure toward its final collapse.

During the permit process, the city’s deputy building engineer expressed concerns about the design, but was pressured into approving the design by his supervisor, who reportedly claimed that the design firm’s principal had convinced him the structure was sound.

In the construction phase, the project’s construction manager, who was later found to have falsified his professional credentials, failed to provide competent oversight; under his watch, a number of construction defects occurred that played a role in the building’s failure.

In 1990, a structural engineer tasked with a pre-purchase review of the building reported to the design firm that the connections between the floors and the north wall did not comply with building codes. While the presence of such an error should have triggered a more thorough review of the design, the firm assumed instead that the reviewer had identified all areas of non-compliance and did not make further investigation.

In 2001, the building’s management applied to the city for permission to lease office space to a language school. Under the applicable law, this change of use gave the city authority to order upgrades for compliance with current codes, but the city elected not to invoke this authority. Later, a second educational tenant leased space in the CTV building, but this time the building’s management failed to notify the city of the change in use.

Finally, after the 2010 earthquake, the building retained an engineer to assess damage to the building. The engineer found obvious damage to non-structural elements, but saw no evidence of structural failure. The engineer asked to review the building’s structural drawings, but the quake had affected the city’s ability to access its archives. By the time copies of the drawings were secured, the engineer had already completed his review, so the copies were not shared. The engineer made recommendations for a further, more thorough, assessment of the building, but this advice was not acted upon.

Questions

1. Did the design engineer violate the Code of Ethics? If so, which specific codes and what actions were in violation?

2. Did the principal violate the Code of Ethics? If so, which specific codes and what actions were in violation?

3. Did the any of the other personnel involved in the design, construction, review, and approval of the building violate the Code of Ethics? If so, who violated the codes, which specific codes were violated, and what actions were in violation?

4. Who is ultimately responsible for the collapse of the CTV building and the deaths of 115 people? Why?

The post On September 4, 2010, a 7.1 magnitude earthquake struck near Christchurch, New Zealand. appeared first on Versed Writers.

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