Couplers used at terminal of Hong Kong’s high-speed rail to mainland China are substandard, government admits
Batches deemed unusable were replaced or discarded, but work on the site had to be stopped for four months in 2013
Substandard metal couplers were used in the construction of the cross-border express rail line’s Hong Kong terminal, the government confirmed on Friday.
The Buildings Department said that structural safety at the West Kowloon terminal was not affected, and that there was “no serious violation” of the law, although building was suspended for four months in 2013 as a result. Batches of couplers deemed unusable were replaced or discarded.
The disclosure came in response to media reports on Friday questioning whether the contractor had replaced all the substandard couplers, which were used on the ground floor and B3 level of the terminus of the Guangzhou-Shenzhen-Hong Kong Express Rail Link in 2013.
The HK$84.4 billion express rail line is set to open next month.
The HK$8.9 billion contract to build the north part of the station was awarded to a joint venture of Leighton and Gammon in 2011. According to the MTR Corporation, which oversees the project, manufacturer Dextra Pacific supplied the metal couplers used to connect steel bars, which reinforce concrete structures.
On Friday evening, the Buildings Department said it received a report in 2013 flagging test results of couplers used at the station.
It then ordered the rail firm’s structural engineer to conduct “in-depth” tests to verify past results. In the first round of testing, on the couplers’ malleability and ability to withstand tension, five samples failed a pulling test, it said.
As a result, all couplers produced in the relevant batches, including those already installed, were discarded or replaced, it said.
Further tests of 211 couplers revealed that eight failed the malleability test by stretching more than the 0.1mm standard. As two of the samples exceeded the limit only slightly, the registered structural engineer judged that using them would not affect the structure's safety.
Couplers produced in the batches related to the six other failed samples, however, were replaced.
“As the incident did not affect the structural safety of the construction project, and there was no serious violation of regulations under the Buildings Ordinance, the department did not press charges or punish relevant individuals,” the department spokesman said.
Because of the findings, work on the concrete structures paused between June and September 2013, he said.
The spokesman did not disclose the number of batches or the number of couplers affected.
The rail firm, which has been involved in a series of scandals related to its Sha Tin-Central rail link project – one of which also involved couplers, in that case improperly fitted – said the government had deemed the express rail project safe for operation.
“Since the incident, the MTR Corp has strengthened monitoring for the preparation process and tests, to ensure the quality of the regular tests,” it said.
Dextra China general manager Charles-Michel Gauthier said the couplers supplied by the company “were in compliance with the specifications set by the MTR Corporation and the Buildings Department”.
Gauthier, however, did not explain why some couplers failed the tests in 2013.
Civil and structural engineer Simon So Yiu-kwan agreed that it was acceptable for the Buildings Department to retain the batches of substandard couplers that only slightly exceeded the tolerance limit.
“For those couplers which exceeded the standard by over 0.1mm, they could not be used for screwing steel bars, as the gap between them will be big and steel bars could easily slide out. They have to be rejected,” he said.
Civic Party legislator Tanya Chan said there were “serious loopholes” in the Buildings Department’s monitoring system, as it only found out about the incident after it was tipped off.
She called for a thorough inspection of all express rail facilities before it opens next month.
Additional reporting by Cannix Yau