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Construction : Guest Article | May 2016 | Source : CW-India

Structural Collapses | Don't Hang the Engineers!

PROF DR KIRTY DAVE calls for expert, forensic testimony to analyse building collapses before apportioning blame.
With the coming down of a bridge under construction in Kolkata, we have once again raised our voice, shouting, 'Hang the engineers and contractors or put them behind bars.' There is neither an expert report nor even a glance at design calculations or a bit of debris or fragment of metal being examined or tested. In contrast, let us see what the law elsewhere states and how such problems are tackled.

Take the case of Hyatt Regency, a leading American hotelier known for being meticulous that makes sound, sturdy, comfortable and aesthetically beautiful buildings. Its Kansas City hotel was made up of three interconnected buildings with three walkways at different levels that hung from floors above.

The purpose of the walkways was to reduce congestion at the atrium level. On July 17, 1981, the atrium was playing host to a tea dance with over 1,600 people in attendance. Suddenly, the fourth floor walkway dropped from its hangers, the second floor walkway hung from the fourth floor walkway, and the two began to collapse together, coming down on the crowd. With 114 dead and over 200 injured, this was the worst structural failure in the US of its time. The claims amounted to over $3 billion, and 90 per cent of them were reportedly settled out of court. The cause of the accident: A simple mistake on the part of construction management of introducing an additional hanger from the intermediate floor.

A little difference between the original design and a change in the walkway 'as built' caused the tragedy.

Indeed, structures, as awe-inspiring as they may be, are inherently sensitive. Even the slightest change in size and placement sequence can cause a huge disaster. Here, a single continuous hanger of a two-tier bridge substituted by two independent hangers caused the disaster. Such minor aspects could escape the attention of even the most qualified experts. Also consider the example of Tacoma Bridge, which connects Seattle and Tacoma. In November 1940, wind twisted the span, leading to a collapse. The designer overlooked the need to stiffen the trusses against the turning moment of all possible wind velocities.

India is no stranger to failures of buildings and bridges (See box on Bridge Failures in India). And every time a structure collapses, we hear the same refrain about booking the builders, arresting the engineers and catching hold of the designers, without pausing to introspect further.

When the area from Kutch to Ahmedabad suffered shocks from an earthquake, we heard the same noise. Over 40 to 50 engineers and architects went underground. Even when a building over 100 years old collapses, some engineers from the lower cadre go to jail. Every building collapsed is associated with a few corrupt engineers and architects.

This is not to say that professional ethics should not be maintained to a high degree. Let's recollect the story of the City Corp Tower of Manhattan, which highlights the need for an engineer to be super-sensitive of ethical standards. The tower was designed by leading American structural engineer and MIT and Harvard professor William J LeMessurier. After the building was completed and occupied, he received a phone call from a student, who apprised him that there were errors related to joint weakness under wind forces, aggravated by the substitution of bolted joints in place of welded connections. Once he rechecked and confirmed the deficiency, LeMessurier, putting public safety first, took the honourable step to come clean. Subsequently, corrective steps were successfully taken at a cost of about $8 million; to this, he offered $2 million, the limit of his liability coverage.

Our professionals would do well to emulate the high standard of professionalism demonstrated by LeMessurier. Having said that, it is only in the event of criminal negligence that legal action can be justified against contractors, consultants, engineers and others. The entire 'Doctrine of Negligence' depends on expert testimony. In Clark vs City of Seward (1983), Engineering Science of Alaska (ESAL) contracted the City of Seward, to perform engineering services as required for the design and construction of a sewage treatment plant and for the extension of the city's water and sewer systems to a new subdivision. The city alleged that ESAL's performance of the contract did not meet the community standard of competent engineering practice and that its episodic work pattern and inadequate designs proximately caused the city's injury. The city alleged that ESAL failed to use good engineering judgment and represent the city's interests in an unbiased manner before government agencies. The contract was terminated. The city claimed for damages for hiring another engineering firm and filed for damages amounting to $79,000. Expert evidences were led in the matter. The Alaska Supreme Court did not conclude 'negligence' in the absence of categorical expert opinion.

In the present Kolkata case, the failure is owing to design fault or construction and erection deficiency. In the event, there is no design fault, the designer cannot be held responsible merely because the structure has come down. There could be many causes for the disaster other than design deficiency.

FIRs mention act of negligence under sections 304, 337 and 338 of IPC in all cases of collapse or failure. It is surprising that in the MHADA case related to transit camps at Borivali, sub division for infructuous expenditure was incurred on the said repair works without any adequate, sufficient or cogent reasons.

A disciplinary action was initiated.
A senior investigation engineer deposed that 'there were rat problems and the foundation was okay' and that ├┤some corrosion to structural steel was noted.'

Unfortunately, society does not involve the expert engineers in the field and architects in the investigation of failures right from the beginning. It would be of benefit to clearly ascertain the cause of failure. In order to do so, we need systematic investigation. This would require us to have a specially trained, professional forensic engineer, capable of applying engineering science to investigation. It is only a forensic engineer and not the police that could really help an interested judge understand the physical cause of failure.

We have neither introduced the study of law in engineering nor developed forensic engineering as a field of practice. We do not have trained expert witnesses and the entire subject of a collapse remains more in the domain of the police, who are not even trained to collect samples from the site. Let us thoroughly investigate the cause of any such incident and have testimony from experts, not police or advocates.

Bridge Failures in India
CW offers a list of bridges that over the years have been reported with notable failures.
1982: The Sewa Nagar Flyover, built in a rush to meet deadlines for the Asian Games in Delhi, collapses.
2001: A 120-year-old bridge gives way, causing a train to fall into the Kadalundi river in the southern state of Kerala, leading to 59 deaths.
2005: A flash flood sweeps away a small rail bridge in Valigonda, south of Hyderabad in Andhra Pradesh, and a 'Delta Express' train traveling on it derails at the broken section of the line, killing at least 114 people and injuring over 200.
2006: An arch of a 140-year-old bridge falls onto an inter-city passenger train in Bhagalpur in India's Bihar state, killing 34 people.
2007: Flyover Bridge under construction in Panjagutta at Hyderabad, Andhra Pradesh, collapses killing 15 people and injuring many.
2009: Kota Chambal bridge, while under construction, collapses killing nine people and leaving 45 missing.

2013:

  • A flyover being built near Mumbai's international airport collapses killing three people and injuring seven more; a large slabfalls during late hours in the night trapping several people, mostly labourers, underneath it.
  • A road over bridge falls on a goods train in Bihar's Muzaffarpur, injuring 14 people.
  • A huge portion of a flyover at Ultadanga in Kolkata collapses, injuring three people. 2014: A 35-m-long concrete slab of a flyover under construction near the New Court building in Athwalines in Surat collapses, killing up to six labourers.
  • 2015: Three people get seriously injured as a portion of the under construction Wazirabad-Janakpuri bridge collapses in the Pitampura area of Delhi.

2016:

  • Vivekananda bridge in Kolkata collapses when under construction reported killing at least 17 people and leaving scored of others trapped under the debris.
  • Shuttering between two under construction metro pillars in Lucknow collapses while workers fill concrete to reinforce the portion between them, reportedly causing injuries to eight labourers.

About the author:
Prof Dr Kirty Dave is a chartered engineer, adjunct professor at IIT-Bombay and techno-legal consultant. As an engineer (Project Engineers), he has executed dams, bridges, canals, industrial plants, warehouses and residential and office complexes for the past 30 years.

 
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