Past metro probe body prescribed what to do, but failed to detect main culprit: Experts
After last year’s metro rail accident, the investigation committee had recommended checking all bearings; DMTCL claims they acted on the safety-check recommendations
Highlights:
- Second bearing pad collapse near Farmgate kills pedestrian
- Previous probe warned of risks but lacked accountability findings
- Experts blame design flaws, substandard materials, poor construction
- Committee's recommendations were partly followed but insufficiently enforced
- Investigation committee lacked independence, mostly internal members
- New six-member probe formed after latest fatal incident
Just two piers away. A bearing pad on Pier 430 collapsed a little over a year ago, and on Sunday, a similar incident repeated – the bearing pad on Pier 433 fell down, this time killing a pedestrian. Both incidents occurred in the same area, near Farmgate Metro Station. Since the latest incident, experts were telling if the factors caused by the past incident were addressed, the repetition could have been checked.
Analysing the previous probe committee's report, which was not made public or discussed, they pointed out that although the probe body recommended countermeasures to check recurrence of such collapse, it stopped short of identifying who were responsible.
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The past probe committee, formed after the bearing pad collapse on 18 September last year, recommended that bearing position shall be checked physically at all curved sections, gradient sections and in and out of stations along and drone shooting of all bearing positions to preserve photographs as record. Checking of track parameters at the section, installation of lateral protection on the affected pier and replacement of the dropped down bearing by a new one within one month were among the short-term measures recommended.
The probe body also stated the contractor should provide the bearing manufacturer's quality assurance check certificate.
Dr Shamsul Hoque, retired professor of Civil Engineering at Buet, said the falling of the bearing pad on the Dhaka Metro Rail and the review of the investigation committee's report show that this incident is not just an accident. It is the result of construction defects and substandard materials, he noted.
"The recommendation to replace such an important component so quickly proves that the work was not done according to proper standards," said the communication and infrastructure strategist.
The past probe committee also suggested that the detailed design of the bearing pad and its base including the installation method shall be reviewed to avoid repetition of the same incident in MRT Line-6. As a long-term measure, it suggested root cause and countermeasures shall be considered in other MRT lines to avoid repetition of the same incident especially in the curve and gradient sections in the DMTCL network.
Among the possible reasons for last year's incident, it identified some structural factors such as repeated deflection of the girder due to train's running, effect of centrifugal force as well as impact of temperature change on track, curve section and track structure.
"In fact, the bearings on P428 and P429 have a slight shear deformation toward the same direction of the dropped down incident on P430," the probe committee said in its report, suggesting that the effect should be analysed by track experts and structural experts as well as the contractor concerned.
"Something specific component of the rubber bearing material, which is purposed for improving the durability against ozone deterioration effect, might have reduced the slip-resistance on the surface," the report stated.
Dr Md Hadiuzzaman, professor of the Department of Civil Engineering at Buet, told TBS, "Accidents of two bearing pads at the same location consecutively can occur for almost the same type of reason. If the recommendations had been acted upon then, such an accident at the same location could not have occurred."
The main causes were design flaws and curves, which experts had pointed out after the previous accident, he added.
When asked whether any measures were taken according to last year's committee recommendations, Faruque Ahmed, managing director of DMTCL, said, "We monitored the bearings at that time based on the committee's report and also had them checked by experts. The contractor was given an opportunity to fix the issue under the contract's defect liability clause. At the same time, our team conducted regular monitoring and found no problems in that section."
Abdul Baquee Miah, Director (planning and development) of DMTCL, who was the convenor of the past probe committee, also told The Business Standard that the DMTCL acted as per probe committee's recommendation.
Another member of the committee, who preferred not to be named, said, "All bearing positions were inspected after the past probe body's recommendations." Routine check-up was carried out just a few days ago at the same site where Sunday's incident occurred, he added.
Culprit for the past incident not detected
According to the construction contract, the contractor must replace or repair any defect during the warranty or guarantee period at their own expense.
Prof Shamsul Hoque said the investigation report, though recommended replacing the bearing pads within a short period, did not clearly state who will bear the cost – the contractor or the DMTCL.
If the DMTCL pays for this, it would set a dangerous precedent where substandard work goes unpunished, he said, stressing that it is crucial to recover the cost of replacement and related compensation from the contractor.
Holding parties accountable will force contractors and supervisory firms to act more carefully and maintain higher standards in future projects, he felt.
If the investigation committee only advises on "what should be done," it will not stop the culture of negligence or impunity, he added.
Last year's investigation committee incorporated members internally, even included the consulting firm in it, with no independent members.
Of the seven members of last year's committee, five were from DMTCL, and the remaining two were from the consulting firm NKDM Association.
Highlighting doubts about the investigation committees themselves, Prof Hadiuzzaman said, "This accident happened due to the failure of the MRT's contractor, management, or consulting firm, yet last year's committee consisted of these very parties. Naturally, they would frame what they consider the correct causes and subsequent measures. Because of this, the real causes and flaws of the accident were never made public."
After Sunday's accident, a six-member committee was formed under the chairmanship of Mohammad Abdur Rauf, secretary of the Bridges Division. The committee members are ABM Toufique Hasan, professor of Mechanical Engineering at Buet; Lieutenant Colonel Md Jahidul Islam, associate professor of Civil Engineering at MIST; Mohammad Abdul Wahab, project director of DMTCL (Line-6); an additional chief engineer from LGED; and deputy secretary Asfia Sultana, who will serve as the committee's member secretary.
