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Editorial : Steel bar inspection must stand up to scrutiny

【明報專訊】TO tackle the construction problems of the platforms at Hung Hom Station of the Shatin-Central Link, the MTR has submitted a plan to open up the concrete at not fewer than 80 locations to inspect the connections between steel bars and couplers. The hearing by an inquiry commission looking into Hung Hom Station's construction problems has gone on for nearly a month and a half and many witnesses have given contradictory statements. The only way to find out the truth is to open up the concrete to inspect the steel bars. The government must ensure that platform safety is the first priority. It must not relax the requirements concerning the inspection of the steel bars for the sake of opening the Shatin-Central Link on schedule next year. The MTR has wasted a lot of time over the last six months because it has been trying to avoid opening up the concrete to inspect the steel bars. The plan to open up concrete at random locations as proposed by a team of the Hong Kong University commissioned by the government is more reasonable. The public has no way to judge whether the number of random checks is sufficient and can only put their trust in the experts. To ease public doubts, the government's Expert Advisor Team for the Shatin-Central Link Project and the HKU experts can provide more explanations. If the initial inspections show that the problem is severe, the sample size should be expanded.

For a long time, the MTR has not been facing squarely the problem of shortened steel bars at the platforms of Hung Hom Station. Initially it proposed only to test the loading capacity of the platforms. It was only when the government found out that the MTR investigation report had not been telling the whole truth that it was decided that the concrete must be opened up for the inspection of the steel bars. However, the MTR tried to muddle through. Last October, the company submitted a test plan and proposed to open up the concrete in only 10 places of the platform slabs along the east-west corridor to examine the coupler connections. The Expert Advisor Team appointed by the government rejected the plan on the grounds of its narrow scope.

The "shortened steel bars" saga has compromised the credibility of the MTR. The recent plan will ease the public's doubts because the locations for inspection will be selected randomly and independently by experts from the HKU rather than allotted by the MTR or the government. The MTR has emphasised that the locations will be selected by means of the internationally established method of random sampling and that it is a stringent sampling method. Some civil engineers think that the sampling density is acceptable while others think that the sample size is too small.

Sampling in statistics and opening up concrete to inspect the steel bars both require professional knowledge. Ordinary citizens do not have the knowledge and can only put their trust in experts. If the government's Expert Advisor Team for the Shatin-Central Link and HKU's engineering experts who designed the random inspection explain the plan in layman's terms, it will help to ease the public's doubts. The government and the MTR should also consider publishing an interim inspection report to inform the public of the preliminary results of the inspection. If it is found that the problem of fabrication is severe, the scope of inspection should be expanded to ensure that the final findings of the inspection are credible.

There have been a lot of problems in the construction of the platforms at Hung Hom Station. Opening up the concrete to inspect the steel bars is the only way to salvage public confidence. Even if it is found later that the process of inspecting the steel bars is more complicated and time-consuming than anticipated, the authority should not rush to conclude the structural assessment exercise for the sake of opening on schedule the Tai Wai to Hung Hom Section in the middle of next year. If the inspection proves that there have been severe violations of rules in the construction of the platforms, the government must find out who is culpable and make them pay compensation. Whether it is the MTR, the contractor or the sub-contractors, none should be allowed to get away with it.

明報社評2018.12.06:鑿石驗筋不能馬虎 結果須經得起考驗

沙中線紅磡站月台工程問題,港鐵提交「鑿石驗筋」方案,鑿開至少80處位置,檢查鋼筋及螺絲帽接駁情况。紅磡站調查聆訊至今接近一個半月,不少證人供辭矛盾,弄清真相唯有鑿石驗筋。政府必須以月台安全為先,不能為了趕及明年通車,放鬆驗筋嚴謹程度。過去半年,港鐵對鑿石驗筋諸多逃避,浪費不少光陰,今次隨機抽樣開鑿安排,由政府委託港大獨立進行,做法較為合理,至於取樣數目是否足夠,市民無從判斷,只能相信專家。政府的沙中線專家顧問團,以及港大方面的專家,可以多作解說,減少疑惑,倘若初步驗筋顯示問題嚴重,當局便應擴大抽驗規模。

港鐵對於紅磡站月台剪短鋼筋問題,諱疾忌醫多時,不願面對現實。港鐵最初僅提出以負載測試確認月台承托力,後來政府發現港鐵調查報告不盡不實,決定鑿石驗筋,港鐵仍然試圖敷衍了事。今年10月,港鐵向政府提交的檢測方案,僅建議鑿開東西走廊月台層板10處石屎,檢驗鋼筋接駁,政府委任的專家顧問團批評檢查範圍太窄,將方案「打回頭」。

「剪筋門」重挫港鐵誠信,由港大專家負責獨立抽樣檢查安排,避免由港鐵或政府指定位置,有助減少公眾懷疑。港鐵強調,今次是以國際認可方式隨機抽樣檢驗,取樣方法嚴謹,有土木工程師認為抽樣密度可以接受,亦有人認為採樣數量太少。

統計學取樣方式是專門學問,鑿石驗筋亦要有專業知識。一般市民並不具備這些知識,只能相信專家判斷。政府的沙中線專家顧問團,以及負責抽樣檢查安排的港大工程專家,若能深入淺出公開解釋,可以減少市民疑惑。政府和港鐵可以考慮發表中期檢測報告,交代初步檢測情况,若發現造假嚴重,便應擴大鑿石驗筋規模,確保最後得出的檢查結果更具公信力。

紅磡站月台工程問題多多,鑿石驗筋是挽回公眾信心唯一方法,即使日後當局發現驗筋工作比原先預計複雜、耗時較預期為長,也不能為求趕及明年中啟用大圍至紅磡段,讓結構評估工作草草收場。倘若抽查證實月台工程違規嚴重,政府必須追究責任和損失,絕不能讓港鐵、承建商和涉事分判商輕易脫身。

■Glossary

squarely : directly or exactly; without confusion

muddle through : to attain one's object by good fortune rather than good management

culpable : responsible and deserving blame for having done sth wrong

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