Design flaws in Hong Kong mega bridge building could put workers in deadly danger of electric shocks, experts warn
Power supply rooms located in basement of passenger clearance building on artificial island – and prone to water seepage
Serious design flaws in the immigration building of the Hong Kong-Zhuhai-Macau bridge could be deadly for workers, engineering experts warned on Monday, with power supply rooms located in the basement prone to water seepage.
The warning came after video footage emerged showing serious flooding and water seepage in a basement inside the passenger clearance building – built on an artificial island – on the Hong Kong side of the multibillion-dollar mega bridge, including the transformer room and switch room.
The video clips were reportedly filmed between February and June with footage showing black smoke coming from the switch room taken in late June.
The HK$8.4 billion (US$1.1 billion) building contract was undertaken by a joint venture between Leighton Contractors (Asia) and Chun Wo Development Holdings. Both firms were not available for comment.
Leighton has recently been embroiled in a series of construction scandals involving the HK$97.1 billion Sha Tin-Central link, Hong Kong’s costliest rail project.
The Hong Kong government has spent nearly HK$120 billion on the local section of the bridge, which has been hit by construction delays and cost overruns. The bridge is expected to open some time this year but so far the central government has not announced a date.
Civil and structural engineer Simon So Yiu-kwan said that placing the transformer room and the switch room in the basement was a serious design flaw.
“Usually the transformer room and switch room are located on the ground floor, not the basement as that is where water leakage easily crops up,” he said.
“The basement of the passenger clearance building is prone to underground water leakage problems as it is built on an artificial island surrounded by sea. Its transformer room and switch room should not have been placed in the basement.”
He warned that leaking water could easily cause short circuits in the electrical system and explosions in the equipment because of the very high voltages involved.
“It will be very dangerous as short circuits can kill people,” he said.
So said the best way to resolve the matter would be to relocate both rooms to the ground floor.
“But the move would take at least three to four months, meaning it would be impossible for the bridge to open this year,” he said.
Civil engineer Albert Lai Kwong-tak said construction workers were being put at a risk as the basement should be free of water before the transformer room was connected to the power supply.
“From the video clips we can see that the flooding was very serious in the transformer room but the power supply was already connected,” he said.
“The black smoke from the switch room’s electrical panels indicated a risk of explosions. This put workers in a very hazardous situation. The Highways Department needs to explain how it monitors the safety of this building,” he said.
Civic Party lawmaker Tanya Chan blasted the department for a lack of supervision, adding that government representatives were supposed to be monitoring work at the site.
“It’s common sense that water and electricity should be kept separate. Why did officials manage the facilities in this way?” Chan said.
She accused officials of putting the safety of workers at risk, and that it was not the first time water leakage problems were found at the bridge site.
Lawmaker Michael Tien Puk-sun, of the political party Roundtable, said leakage was common in buildings and there were circuit breakers and other measures to pump water out to prevent explosions. But he said he was concerned about the situation because the video showed plumes of smoke, a rare occurrence. He called on the department to explain the matter.
The Highways Department did not respond to inquiries.