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Results of Review on Concrete Compressive Strength Under Hong Kong-Zhuhai-Macao Bridge Hong Kong Projects and Tuen Mun-Chek Lap Kok Link Project

     Following the press release dated July 7 announcing progress of the additional concrete compressive strength tests under the Hong Kong-Zhuhai-Macao Bridge (HZMB) Hong Kong projects [i.e. Hong Kong Boundary Crossing Facilities (HKBCF) and Hong Kong Link Road (HKLR)] and the Tuen Mun–Chek Lap Kok Link (TM-CLKL) project as a result of the alleged falsification of concrete cube tests reports by a laboratory outsourced by the Civil Engineering and Development Department (CEDD), the Highways Department (HyD) announced today (November 15) results of the review on the concrete compressive strength for the three projects. All test results met the standard.

      However, to ease public concern, the HyD engaged a professional organisation on May 31 to conduct an additional comprehensive and systematic review on the concrete compressive strength of concrete used in the above-mentioned three projects. The Standing Committee on Concrete Technology of the CEDD agreed to the testing proposal including the scope of the additional review and the sampling method, etc. as formulated by the professional organisation.
     The professional organisation completed the review in October 2017 and submitted to the HyD a professional assessment report on November 8. The professional organisation has carried out adequate testing and analysis of the concrete used in structures (including the above-ground or above-sea structures and below-ground or below-sea structures) under the above-mentioned three projects. All test results and analysis indicated that the concrete compressive strength met the standard.
The review on the concrete compressive strength at the locations corresponding to 346 concrete cube test results
     For the structures corresponding to the 346 numbers of concrete cube test results with abnormalities, including 179 above-ground or above-sea structural locations, 96 below-ground or below-sea structural locations (including piles) and 71 non-structural locations, the professional organisation recommended that the HyD should carry out the following additional review:

  1. Carry out non-destructive testing (commonly known as Rebound Hammer Tests (RHT)) for examining the concrete compressive strength at 176 above-ground or above-sea locations. For the remaining 3 above-ground or above-sea locations, although RHT cannot be carried out, the concerned concrete types have been tested under the comprehensive review on concrete compressive strength;
  2. Take 94 sample cores from above-ground or above-sea locations for concrete compressive strength tests; and
  3. Take 345 sample concrete cores from 115 concrete cores taken from piles for concrete compressive strength tests.

     All test results met the standard.
Comprehensive review on concrete compressive strength of the three projects
     From May 19 to June 21, the HyD completed RHTs at the stress-critical locations of the structures (approximately 3 000 locations) under the HZMB HKBCF and HKLR projects, and TM-CLKL project. All test results met the standard.
     In addition, according to the recommendation from the professional organisation, the HyD conducted additional comprehensive tests on the concrete used in the construction of the structures (including the above-ground or above-sea structures and below-ground or below-sea structures) from January 2013 to March this year under the above-mentioned three projects as given below:

  1. Carry out approximately 5 000 RHTs at structures including bridge decks, bridge columns, buildings and tunnels etc.;
  2. Take 95 sample concrete cores from above-ground or above-sea structures for concrete compressive strength tests; and
  3. Use approximately 750 concrete cubes tests results to calibrate and refine the RHT results against the compressive strength test results in accordance with the international standards.

     All test results met the standard.
     Beginning from mid October, the HyD has been conducting load test on the whole 9.4km long Hong Kong Link Road viaduct in phases to confirm its compliance with the design.
     The load test is being conducted on all the spans of the viaduct using a group of vehicles with a total weight of 380 tons comprising a tracker and trailer of about 200 tons and six trucks of about 30 tons each. According to the preliminary test results, all the spans tested so far complied with the design requirements.


Ends/Wednesday, November 15, 2017