Knock Bridge, B8035 Mull

Update Details
Bridge Closure and Planned Programme of Work (18/04/17)

Knock Bridge on B8035 is closed until late June to allow strengthening works to be carried out. 

Currently the programme of work is as follows:

  • Knock Bridge closed to traffic until completion of works – currently anticipated to be late June.  *Please see note below regarding pedestrian access.

  • Tuesday 18th April until late May – works carried out to the bridge’s masonry.  We will endeavour to open the bridge between phases of work if safe to do so.  If we are able to open the bridge between phases it will be at either 3t or  7.5t restriction.  As work progresses we will keep this page updated to reflect any anticipated openings to traffic.

  • Late May until Mid-June – Ties installed by specialist contractor.

  • Late June - Road surfacing reinstated.

  • End of June – Knock Bridge reopened to traffic at previous 33t capacity.

     

    *Pedestrian Access

    Pedestrians & pedal cyclists on foot will be accommodated whenever it is safe to do so throughout the works.  Pedestrian access will be managed in the same way as during the previous bridge closure in February.  Any cyclists wishing to cross Knock Bridge will be able to dismount and walk their bikes over.  Any unsafe-to-cross periods will be kept to a minimum and we do not anticipate any long periods when the bridge cannot be crossed at any point during the works.  The previous closure did not involve any long periods and whilst the works are for the entire bridge this time, the section repaired in February required more intensive repairs than the sections being repaired this time.  If anything unforeseen happens during the works that would affect pedestrian access in any way, this page will be updated immediately.

Explanation of Reduced Weight Restriction Prior to Repairs

The B8035 from its junction with the A848 in Salen to the entrance of Balmeanach Farm has a weight restriction of 33 Tonnes Maximum Gross Weight (MGW).  From the entrance of Balmeanach Farm to the B8035/A849 junction the weight restriction is reduced to 18 Tonnes MGW.  Following a recent bridge inspection, Knock Bridge was reduced from a 33 Tonne MGW to a 7.5 Tonne MGW weight restriction, which is now causing some local issues in regards to the transfer of goods by road.

Knock Bridge is a 13m single span masonry arch dating from the 18th Century and is a Category B Listed Building.  The bridge in in poor condition due to overloading and although limited remedial works have been completed the bridge is still showing significant distress and for this reason it was considered that a7.5T MGW temporary weight restriction was appropriate.  Our Structures Engineers are currently considering options to repair the bridge.

The 18T MGW weight restriction is in place over a weak section of the B8035.  Within the last week, timber haulage operations have been suspended on this section of road due to significant damage to the carriageway.  The Traffic Regulation Order “The Argyll and But Council (various Roads, Isle of Mull) (Weight and Length Restrictions) Amendments Order 2011” allows users to request an exemption to the MGW weight restriction through the issue of permits by ABC.  It is important to note that the permit system still only allows the  maximum weight of the restriction to be carried over a route, for example, a vehicle with a tare (empty) weight of 10T may carry a load up to 8T over a route with an 18T limit (tare weight + load).

The Council are aware that the current situation is causing some difficulties among the users of the B8035 and we continue to work toward a solution.  In the meantime we will work with local residents, groups and businesses and we aim to help as much as we possibly can.  We would like to remind users that they should be aware that it is an offence to breach the weight restrictions.

View the map of the weight restrictions

 

A Note Regarding the Lack of Vehicle Access during the Works

Pedestrian access is being maintained at all possible times, whenever it is safe to do so.  Unfortunately vehicular access cannot be maintained whilst works are underway due to the narrow width of the bridge.  A temporary vehicle bridge has been considered, but would incur too long a delay to the urgent work.   Ground Investigations would have to be undertaken to determine the requirements for any form of temporary bridge and its accompanying abutments and road approaches.  Following this, planning approval would then be required before proceeding with a tender process and extensive construction period.

At any opportunities between phases of work, we will endeavour to open the bridge to light traffic if safe to do so.

Argyll & Bute Council are working to achieve the best outcome for the area, with Knock Bridge’s capacity being returned to 33t as soon as possible.