Cracks have been found in the exterior concrete walls of the Hong Kong Convention and Exhibition Centre in Wan Chai, as the scandal-plagued rail operator MTR Corporation revealed the extent of its subsidence problems on the Shatin-Central Link project yesterday.
An engineering expert said the cracking was likely caused by subsidence, although the risk they posed would depend on whether the building had sustained structural damage.
According to subsidence data submitted by the MTR to the Legislative Council yesterday, the readings at 73 monitoring points around the nearby Exhibition Centre station site have exceeded “trigger levels” – the points that require further actions.
The rail operator was earlier ordered by the government to halt all excavation work at the site, but construction of the Central – Wan Chai Bypass is still ongoing in the same area.
The cracks, some more than 10 metres tall and spanning from floor to ceiling, are mainly located at the base of the building’s second phase. Many are still visible despite apparent repair work.
The cracking is especially prominent on a north-facing wall along Expo Drive, which is covered by hairline fractures.
A crack has appeared on both sides of a two-metre thick wall at the centre’s loading area, while another wall on the east side has also developed extensive cracks.
Veteran civil engineer Ngai Hok-yan, who has seen photos of the cracks, said the diagonal cracks were created by tension between the building’s core structure and non-structural walls.
Although the cracking was likely caused by subsidence, whether it indicated a safety risk would depend on the integrity of the core structure, he said.
He added that the cracks did not appear to pose extensive danger, but wall decorations, such as mosaic tiles, could fall off and hit passerby.
An industry source has told FactWire that Expo Drive had been sinking extensively due to the construction of the Central – Wan Chai Bypass, but the road was resurfaced overnight in early 2015 after receiving complaints.
According to the MTR data, parts of the roads near the future Exhibition Centre station, including Expo Drive, Fleming Road and Convention Avenue, have sunk beyond the predetermined trigger values, but they are deemed to be safe after repaving work.