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Hong Kong-Zhuhai-Macau bridge

No repairs needed for island part of mega bridge, Hong Kong highways chief says amid safety row     

Meeting with mainland authority ends with city’s government saying it is satisfied with the design, which can withstand mega waves that come ‘once in 300 years’

PUBLISHED : Monday, 09 April, 2018, 9:45pm
UPDATED : Tuesday, 10 April, 2018, 10:29am

The sea wall of an artificial island that makes up part of the cross-sea bridge infrastructure linking Hong Kong to Zhuhai and Macau is structurally sound and safe, the Hong Kong government confirmed on Monday after a site review, quashing concerns that it was drifting apart.

Director of Highways Daniel Chung Kum-wah stressed that the structure completed last year had not deviated from its final design, and therefore no repairs were needed. 

Chung, who paid a site visit the day before, said he was also satisfied with the explanation by mainland officials who head the Hong Kong-Zhuhai-Macau Bridge Authority, the body responsible for building and managing the multibillion-dollar project.

Concerns surfaced earlier this month after aerial photos taken by a drone hobbyist appeared to show that interlocking concrete blocks placed around the edges of the artificial island – which connects the Hong Kong bridge section to a tunnel in mainland waters – had drifted away.

The blocks, known as dolosse, weigh five to eight tonnes each and are meant to absorb the impact of strong waves and protect the island and tunnel.

The authority has since issued two statements to dismiss safety concerns, arguing the blocks were “randomly” positioned in the waters by design to maximise efficiency.

But the explanation failed to convince some engineers, prompting a meeting between the Highways Department and the authority in Zhuhai on Sunday.

Returning from the trip, Chung said the conclusion was that the positioning of the dolosse was “scientific, reasonable and safe”.

“We also inspected the building plans and photos taken over a period of time. We do not see any discrepancies from its intended design,” Chung said.

We do not see any discrepancies from its intended design
Daniel Chung, Director of Highways 

He presented a series of aerial photos taken in May 2017 – when construction of the island had been completed – as well as in August that year, when killer Typhoon Hato battered the region. All photos showed a similar shape for the structure.

Principal Government Engineer Raymond Kong Tai-wing said the dolosse were positioned in two ways at the site because they served different purposes. 

Those which were stacked near the island and rise above the water surface were there to absorb the force of the waves. Others, including those which appeared to have been washed away, were scattered in the nearby waters to prevent vessels from sailing too close and damaging the undersea tunnel.

“These blocks are placed as far as 130 metres away from the island, but some are not visible as they are submerged,” Chung said. He dismissed the need for any repairs for the sea wall, adding they were designed to withstand waves which were so powerful they occurred only “once in 300 years”.

Veteran engineer Albert Lai Kwong-tak, who is also the convenor of the Professional Commons think tank, said he was satisfied with the explanations about the placement of the concrete blocks but added that some questions remained unanswered.

“The director has still failed to tell the public whether it is the best design and what other designs the mainland side previously considered,” Lai, who has been critical of the project, said.

He said he hoped the government could also ask mainland authorities to present their inspection reports on the integrity of the island’s sea wall.

Civic Party lawmaker Tanya Chan urged the government to set up a notification system with the mainland side to keep Hong Kong apprised of any irregularities in the construction or operation of the bridge.

Meanwhile, speaking on the sidelines of the Boao Forum – an annual summit – on Hainan Island, Guangdong provincial governor Ma Xingrui shunned media questions about the bridge’s safety, saying these should be directed at Hong Kong and Macau authorities. 

The remarks by various sides followed that of Hong Kong Chief Executive Carrie Lam Cheng Yuet-ngor on Friday, who said the integrity of the structure was “scientifically proven”. 

Over the past week, the string of reassurances by authorities and officials reflect the enormity of the situation, which could potentially derail plans to meet a commissioning deadline for the bridge – expected to be July 1, the anniversary of Hong Kong’s return to Chinese sovereignty. 

The city has so far committed to contributing about HK$10.7 billion (US$1.36 billion), or 43 per cent, of the main bridge’s construction cost. But local officials are set to spend another HK$110 billion to build the city’s connection to the main bridge. 

The project has been plagued by budget overruns and construction delays.

Additional reporting by Ng Kang-chung