Probe finds faulty bearing pads, design flaws behind Farmgate metro accident
Investigators rule out possibilities of sabotage
The two bearing pads that came off a metro rail pillar in Dhaka's Farmgate area were defective, an investigation committee said today (1 January), ruling out any evidence of sabotage in the incident.
Road Transport and Bridges Adviser Muhammad Fouzul Kabir Khan presented the findings of the investigation at a briefing at the secretariat.
According to the probe committee, the two bearing pads did not fully meet quality standards in two of eight to ten tested parameters. However, all other bearing pads cannot be classified as either good or bad on the basis of these findings.
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The report attributes the accident to a combination of three factors.
It stated that tests at the Buet lab revealed that the bearing pads used were of significantly lower quality than prescribed standards.
Additionally, the probe body found that design flaws in the metro rail caused excessive train vibrations, leading to the pad's displacement.
The committee also found that one of the bearing pads was installed at a slight slope rather than parallel to the pillar, making it prone to shifting and falling due to vibration.
The committee found that no transition curve was used between the straight and curved sections of the viaduct, pointing to a possible design flaw. No separate model or analysis was conducted for the curved alignment, as the design relied solely on analysis of the straight section, reports UNB.
Investigators also noted that while a mass-spring neoprene damper system is used under tracks at curved alignments and nearby stations, rigid tracks were installed at the accident site. The committee believes the damper system could have reduced vibrations.
Recommendations
Outlining the recommendations, Adviser Fouzul said urgent technical measures must be taken at curved alignments to protect bearing pads.
The committee also called for a detailed review of the viaduct and track design by an independent third-party consultant, along with a comprehensive safety audit of the metro rail project, Fouzul said.
It further recommended establishing a robust structural health monitoring system, strengthening the metro rail authority's technical capacity, and ensuring effective technology transfer from foreign consultants to local experts.
On 26 October last year, a pedestrian was killed when a Dhaka metro rail's load-bearing pad, designed to prevent vibration during train operations, came loose and fell on him.
