Works at Hong Kong MTR’s Exhibition Centre station to resume after acceptable levels of subsidence revised and approved
Transport and Housing Bureau lays down new instructions for rail giant on how to handle subsidence issues in bid to regain public confidence in troubled Sha Tin-Central line
Excavation works at a new station along Hong Kong’s costliest rail line resumed on Saturday, after the rail giant revised the acceptable levels for subsidence around projects.
The new levels, approved by the government, range from 20mm to 95mm – an increase from the previous 10mm to 25mm specified in a paper submitted to the Legislative Council.
Authorities said there were no safety issues, adding that the revised levels resulted from consultation with relevant public utility providers, the Buildings Department and the Highways Department. They also confirmed nearby buildings, structures and utilities around Exhibition Centre station in Wan Chai were safe.
“Only when it is confirmed that the MTR Corporation has sufficient justification, [then] consent will be given to make the relevant update,” a government statement released after 11pm on Friday said.
Chief Secretary Matthew Cheung Kin-chung on Saturday reassured that everything was safe and said construction would be closely monitored, with work to be halted or fixed if any problems were found.
“There is no need to worry as the engineering staff have professional judgement,” Cheung added.
Former Hong Kong Institution of Engineers president Dr John Luk Wang-kwong said what was an acceptable level for subsidence varied for different projects.
“If it is located next to a hill, there is no problem even if the subsidence level increases to 300mm,” he explained. “But close monitoring should be carried out for sites crowded by buildings.”
He said special attention should be paid to any occurrence of differential settlement, which would result in damage to a building’s structure.
Engineering sector lawmaker Lo Wai-kwok added that the revised subsidence levels did not mean safety was being sacrificed, stressing all construction was monitored by professionals.
According to the latest data from the MTR Corp as of September, none of the 121 monitoring points on the HK$97.1 billion (US$12.4 billion) Sha Tin-Central Link reached specified levels warranting a temporary suspension of works.
The MTR Corp suspended works around Exhibition Centre last month after it became the second stop on the line to be hit by subsidence problems, causing public alarm over the project’s safety.
Earlier, more than 100 residents living near the new To Kwa Wan station complained about shaking buildings and cracks in their homes from construction.
The Tai Wai to Hung Hom section of the new line is scheduled for completion in mid-2019, and the cross-harbour part connecting to Admiralty is expected to be ready in 2021.
In a press release on Friday night, the Transport and Housing Bureau announced new instructions for the rail giant – which is 75 per cent owned by the government – on how to handle subsidence issues.
It said the operator should keep an updated list of public facilities and structures related to monitoring points for subsidence levels.
Once subsidence “reached a preset trigger level”, part of the work would be temporarily suspended. This could also be decided by the Buildings Department and the Highways Department, if they deemed the magnitude of the subsidence might “affect the structural safety of structures and safe operation of public facilities in the vicinity”.
The bureau added that if efforts to alleviate suspension posed a risk and needed to be deferred, the MTR Corp would need to notify the two departments.
Authorities would complete an inspection of affected private buildings and public facilities such as gas pipes and water supply pipes within the following 48 hours to confirm they were structurally sound and operating safely.
“Upon completion of the inspection, [either department] and the MTR Corp will issue press releases, reporting the situation of works suspension or temporary deferment of suspension of works, together with the reasons and the monitoring data,” the statement said.
The rail giant would also need to deploy its own structural engineers to inspect affected areas and keep all stakeholders informed. During this period, it could consult experts and update preset trigger levels, but authorities would “vigorously scrutinise” this information before approval.
It would further need to consistently report data on monitoring points to lawmakers on the railways subcommittee.
The MTR Corp has been mired in a series of construction and project mismanagement scandals in recent months. Revelations of substandard construction work and unauthorised design changes at the Hung Hom station eventually forced authorities to demand heads roll among those in charge of the troubled project.
In its statement on Friday, the bureau pledged it would keep on top of the subsidence issue.
“We will … closely monitor the settlement condition of structures and public facilities in the vicinity of works to ensure the safety of the public, construction personnel on sites, as well as structures and public facilities in the vicinity”.
Meanwhile, lawmaker Michael Tien Puk-sun raised concerns over the extra costs, if any, arising from the work suspension that had lasted for more than one month.
The MTR Corp argued that the officials who ordered the halt had to bear the cost, while the government disagreed, he said, noting the amount had yet to be determined.
Additional reporting by Kimmy Chung