HKZMB | Concrete structures alleged to have drifted, fallen into sea

Alarm bells were ringing last week over the apparent drift of a large quantity of concrete structures intended to protect the edges of two artificial islands that form an undersea link along the Hong Kong-Zhuhai-Macau Bridge.

Aerial photographs published by several news outlets showed that the concrete structures, which usually protect the islands from erosion caused by weather and the sea, were set in an unusual, random arrangement and mostly underwater.

This prompted concern in neighboring Hong Kong regarding the structural integrity of the undersea tunnel that links the two artificial islands.

However, officials from the mainland authority responsible for overseeing the bridge project have spoken out and insisted that the concrete blocks are arranged as intended; submerged and scattered in a “random manner”.

The deputy director of the Hong Kong-Zhuhai- Macau Bridge Authority, Yu Lie, told the South China Morning Post late last week that the arrangement of the concrete structures was by design.

“We have our ways to do it, and you [Hong Kong] may have your ways to do it. You seem to presume that part of the structure has sunk, has collapsed. But this has been designed as such. We do not think there is any problem with that. There are rules and standards for us to follow,” he said.

But Yu’s comments were not sufficient to allay public fears that a bad weather event like last year’s Typhoon Hato could damage the underwater tunnel.

Hong Kong’s Highways Director Daniel Chung visited the bridge authority on Monday to investigate the rumors. According to Hong Kong media, Chung said that there was no evidence that the concrete blocks have drifted. He said that their current placement had not changed from the blueprint design.

However, the bridge authority has not released the blueprint to the public, despite calls from engineers to do so.

He also said that, although the blocks have been arranged in a semi-random manner, they are required to meet a density of at least 14 pieces within a 25-square-meter area.

Hong Kong’s chief executive Carrie Lam argued that the bridge’s stability had been “scientifically proven” and that the quality of the project’s construction was not in doubt.

Aerial photographs released by the bridge authority last year – in order to prove the islands had withstood the onset of Typhoon Hato – show a similar arrangement of the concrete blocks as today.

However, digitally rendered images of the bridge prior to its construction show a consistent, non- random arrangement of the blocks, suggesting that it had not always been a part of the design.