13th May 2013
<Cracks Everywhere on Old Buildings Along West Island Line>
2mm Fractures Widen to 6mm cracks, Scholar: Won’t Happen Without Boring
The West Island Line of MTR (HK’s equivalent to subway and underground) will be completed by 2014. Underground boring and blasting works have entered the final stage. Members of the Central and Western District Council, from various political parties, have said that cracks of varying widths have appeared in a number of old buildings along the West Island Line, and are suspected to be related to the West Island Line construction. An owner of one of the affected buildings provided the results of a pre-project survey commissioned in 2009 by MTR Corporation (MTRC), which noted fractures of between 1mm and 2mm wide. The same crack is now 6mm wide. MTRC confirmed that they have received a total of 194 damage complaints since the construction began over three years ago, and there were 70 complaints received as of the beginning of 2012. MTRC claims that the surveyor’s investigation shows that these complaints are not related to the project.
MTRC: Surveyor Confirms Damages Irrelevant to Project
MTRC said that surveyor was hired by the project’s insurance company to review complaints filed by the owners of buildings on the tunnelling route. Since the surveyor is not hired by MTRC, they claim, his findings are independent and impartial. Lawmakers, however, correctly pointed out the obvious incentive for the surveyor to find in favour of his employers, and by extension the MTRC.
The three new stations on the West Island Line are Sai Ying Pun, Hong Kong University and Kennedy Town. The construction involves underground works through densely populated residential areas. Boring machines will be used at the Sheung Wan to Sai Ying Pun section, whilst the Sai Ying Pun to Kennedy Town section requires deep hole blasting works, these works are at their final stage.
According to the documents submitted to the Legislative Council by MTRC, since the project began over 200 residents in the affected area completed about cracks in their buildings. Most of the complaints come from Sai Ying Pun. MTRC confirmed that 194 complains about cracks on buildings were filed in the past three years, whilst 70 of them were filed as of early 2012, which means complaints went up massively in the past year.
The owners of Sun On Building, which is next to the Hill Road entrance to the future Hong Kong University Station, spent HK$5 million (US$650,000) to service the building in 2008. During a recent site visit, dozens of cracks could be seen all over the building. The owners’ representative complained to MTRC about the situation but the surveyor denied liability. Based on video footage filmed at the building in 2009 before the construction work began, none of the cracks was beyond 3mm. However, the recent visit at the building shows that one of the cracks on the seventh floor, which was 2mm wide in 2009, has widened to a crack of 6mm. Another crack in the stairwell has widened from 1mm to 2mm.
After looking at recent pictures taken at the building, Dr. Chan Chi-ming, Head of Department of Construction, Hong Kong Institute of Vocational Education, thinks that the two cracks in the corridors, which are wider at the bottom than at the ceiling are “obviously recently enlarged fractures”. Dr Chan is a qualified civil engineer and a surveyor. He also said that small fractures could appear in buildings as they age, but looking at the current situation with a professional’s knowledge: without the underground boring causing subsidence, the current situation would not have happened. Even if there were small fractures in the building, they would not have widened by this much into cracks which may affect the building’s structure.
Hong Kong Institute of Surveyors Vice President Vincent Ho Kui-yip said it was difficult to come to a conclusion based on the pictures. However, he said the widening of fractures in the building could be caused by external factors including boring work, which have sped up the deterioration of a building which is already aging. The most important thing at the moment is to ensure the safety of the building: He said that the fractures at the stairwell could impact the fire escape route and urged the owners of the building to repair as soon as possible by themselves or discuss with MTRC before repairing.
MTRC Claims to Submit Data Regularly to Building Department, Building Department Gives No Response to Enquiry for 2 Weeks
MTRC’s spokesperson emphasised that the majority of the complaints they’ve received are related to the natural aging or lack of maintenance of the buildings. Based on the data in recent inspection records, they claim it is impossible for the project to have caused the fractures and cracks in the buildings. MTRC also said that they surveyed almost 380 buildings along the West Island Line route prior to the start of the project, and installed inspection points which collect data for the Building Department on a regular basis, to ensure that all the impacts are within the “acceptable range” established by the Department.
Ming Pao has been trying to contact the Building Department since 30th April (that is almost two weeks before this article was published) to ask about their definition of the “acceptable range”, including how the Department came up with the range, and whether the Department followed up with the surveyor’s inspection reports. So far, there has been no reply.
Scholar Criticises: Government Fails to Monitor Closely
Dr. Chan Chi-ming states that even if the data collected by MTRC shows that cracks have not exceeded the set standard, this does not necessarily mean that the project has not caused the fractures in the older buildings. He also wondered if the Hong Kong SAR government has done enough to monitor the project in relying on MTRC to submit data. Regarding other railway projects that are currently under construction, for example the Sha Tin-Central Line and South Island Line, which pass through residential areas, Chan recommended residential unit owners in these areas should ask surveyors to take photographic evidence regularly. He also recommended that the government to improve the monitoring system, or even subsidise individual owners to hire their own surveyors.