MTR Corporation to dig up platforms at Hung Hom station to get to bottom of shoddy work allegations plaguing Hong Kong’s Sha Tin-Central rail link
- Total of 80 spots set to be dug up
- Investigation to cover both upper and lower slabs of the newly built platforms
Hong Kong’s most expensive railway project is facing more uncertainty and scrutiny, with the operator undertaking to break open 80 sections of two newly built platforms at Hung Hom station to get to the bottom of a scandal over shoddy work allegations.
The government announced on Wednesday that it had accepted the MTR Corporation’s revised “holistic assessment strategy” for assessing the structural integrity of the platform slabs and diaphragm walls at the expanded station for the HK$97.1 billion (US$12.4 billion) Sha Tin-Central link.
The operator had initially proposed to work on the platform serving the east-west corridor of the line between Tai Wai and Hung Hom, but was forced by the government to expand the inspection to the platform serving the north-south corridor between Hung Hom and Admiralty.
“We’ve considered that it is a scientific way to identify the problems and the scale of the problems, and the way to resolve the issues,” Director of Highways Jimmy Chan Pai-ming said, explaining the rationale for using random sampling to pick the sections slated for dismantling.
“We think that with this approach, we can assure the public that all the structures constructed by the MTR, with all the verification completed, can ensure public safety, and that the structures will comply with the required standards.”
The overhaul was prompted by a construction scandal that blew up in May, when the MTR Corp was hit by allegations of steel bars being improperly cut to imitate proper installation into couplers on the platforms, and the structure of the supporting diaphragm walls being changed without government approval.
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The first part of a three-stage approach has already been completed with a review of design drawings that were amended and the work records consolidated during construction.
The second stage requires the opening up of the two platforms in two parts, the first of which involves at least 24 sections along the east-west platform. Investigators will check if the steel bars connecting the platform slab to the diaphragm walls at each section, measuring 250mm by 250mm, are consistent with the amended drawings of the main contractor, Leighton Contractors (Asia).
Work will start on Monday.
The second part involves cracking open another 56 sections on both platforms – 28 on each, all measuring 400mm by 500mm individually – to examine coupler connections. In total, that will expose a minimum of 168 bar-coupler connections for scrutiny.
In the third and final stage of investigation, the MTR Corp will consolidate test results and other construction issues, and conduct a detailed structural analysis of the station works to decide if any action needs to be taken.
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Experts will also look into other irregularities identified in a spate of allegations reported by the media earlier this year.
MTR managing director Jacob Kam Chak-pui said the operator hoped to ease public concerns about safety at the station.
The dismantling and reinstatement work is expected to take at least 16 weeks, raising the prospect of delays to the project. The east-west corridor was originally expected to open by mid-2019, while the cross-harbour part was scheduled to launch in 2021.
Chan said it would depend on when the safety tests were completed and what the results were.
Leighton Contractors (Asia) has strongly denied carrying out shoddy work.
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Lawmaker and former railway boss Michael Tien Puk-sun said far more than 80 sections required inspection for a more accurate assessment. The MTR Corp’s plan amounted to inspecting three steel bars at each spot, representing only 0.6 per cent of the total number involved, he noted.
“This is ridiculous,” Tien said. “I was asking for a sample size of 5 per cent – that is, inspecting 10 steel bars in each location.”
Veteran structural engineer Ngai Hok-yan said the sampling size was “marginally acceptable”.