Wednesday, 1 October 2014

County Council committee to debate busway defects

The headline is the simplified version - in fact, the County Council's General Purposes Committee, due to meet on Tuesday, October 7, will be debating expert advice on tackling busway defects. This includes technical advice in respect of both the concrete guideway and the foundations and drainage, as well as legal advice from a QC.

According to the County Council (in its press release), "the technical advice suggests that Bam Nuttall is responsible for defects on the Busway. The report outlines that some parts of the Busway were either not built to the agreed design or don’t comply to national standards specified in the contract.

Defects include
• Shims and neoprene pads were put in without being fixed so they now slip and cause movement of the beams, effecting ride quality.
• Foundations were not deep enough as outlined in national guidelines on certain sections so they could move in the clay conditions.
• Inadequate drainage at two locations
• Joints between the guideway beams that were too narrow to allow for thermal expansion of the beams.
• Some bearings were identified as being out of position. 
• Beams not being restrained enough by brackets so they move.

...the legal advice is that this is a breach of contract and that the Council has a good case and should pursue the contractor for the money to pay for the necessary repairs."

Officers are recommending that councillors should "resolve to carry out works to rectify all of the superstructure, foundation and drainage defects in accordance with the assessment of the Project Manager and the advice of the Council’s expert technical advisers, subject to securing funds from Bam Nuttall in accordance with the defect provisions in the construction contract or alternative legal argument; [and] instruct Officers to initiate negotiations and any necessary legal proceedings to recover the assessed cost of defect correction in accordance with the contract, consequential losses arising from those defects, and any costs incurred to date and incurred in future in investigating and taking advice on the defects."

Full documentation (minus Appendix D - which is confidential to members, and any of discussion of which will take place with press and public excluded) is available here. Some of the sums involved are quite eye-watering (see Appendix B, for example).


  1. Yes, some of the numbers are eye-watering, but they do refer to works over the 40pyear "lifetime" of the busway (eg £172m - and what happens after that?).

    I also notice a reference to "spalling" which I must follow up. I've been concerned about that.

    from para 4.2.1:-
    Option B
    ... it involves monitoring foundations, but for the full 40 year design life of the Guideway, ... in respect of 141 foundation structures considered to be at high risk, including the 36 locations South of Histon where Capita considers foundations already to have failed,

    The evidence seems to be mounting that busways are expensive to build and maintain.

  2. The recommended option is for a 3-year programme of works to commence as soon as possible, at an estimated cost of £30m. Stretches of the busway would be completely closed (along, depending on location on the scope of works there, the adjacent cycleway) and buses diverted. Some foundations would be dug up and deepened.

    A major flaw in the guideway design is that longitudinal bracing cannot cope with the forces from buses braking and accelerating - which is what has caused the gaps between the beams to become uneven, causing them to butt together and crack at the ends.

    The (separate) widespread cracking along the surface - which has exceeded tolerances - will be filled with a resin.

    Altogether a huge engineering operation, which itself will entail risks - not least the risk that lifting the beams will cause further flexing and cracking.

  3. According to the BBC, at the meeting referenced in the original posting, "councillors voted unanimously to begin legal action against BAM Nuttall".


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