Brunel Swivel BridgeBrunel's Other Bridge

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Brunel Swivel Bridge Project 2016

Brunel Swivel Bridge
Investigating what lies under the patches
CONTRACT WORK undertaken up to March 2016:
  • Trial dry-ice and abrasive grit blast-cleaning.
  • Trial cutting out and welding in two patch-repair plates.
  • Trial removal of rivets and hot-setting new rivets to match.
  • CCTV drain survey.
  • Removal of one hydraulic ram, dismantling, inspection and refitting in its pit.
  • KGAL design for method of centring and driving round the deck-structure, provision of costings.
  • Geocon Ltd ground investigations.
  • Hole cut in top-tube end-plates to allow internal investigations.
  • Removal of all 20th century patch-plates, measurement of local plate-thickness.
  • Preparation of outline schedule of work and costings.

Page contents

Preparation and Basic Conservation

It is a concern that any hours we spend can not be counted as match funding until lottery funding has been granted. Work is limited since we are not allowed to start restoration work til we get our funding, so any work has to be investigative.

Volunteers still have useful work to do including clearing rust from inside the holed parts, inspecting interiors, measuring plate-thickness, fitting the timber stops, gardening, refitting the ram that was removed, clearing silt from pits, painting, etc.

Likely dates of work for 2016 (We will working 'one day per month' normally on SATURDAYS rather than a whole weekend):

Sounds like fun? No experience needed, all equipment provided, and you'll get really involved in helping to save Brunel's Other Bridge. We need your help.

Contact Maggie Shapland (Maggie.shapland@gmail.com) if you wish to help. We need to have an idea of numbers.

Overall Details of work

Funding

As you know, the Bridge is listed Grade 2* and is on Historic England (formerly English Heritage) Buildings at Risk Register. Whilst their funding is severely restricted, HE have been supportive in providing modest grants to carry out trials and erect a temporary roof, which were completed by Bristol City and Avon Industrial Buildings Trust with volunteer help last year.

EH/HE were impressed with the Mann Williams (MW) report that resulted from the grant-funded work that we managed on behalf of the council in 2015 and suggested that we discuss an application for further investigative work on critical areas identified in the report as part of this year's Heritage at Risk programme. They also suggested that we might request further assistance in other areas via their consultancy budget and service.

You can make a donation by

The main donation link is: https://mydonate.bt.com/charities/brunelsswivelbridge.

We have created a project on http://www.neighbourly.com to also help us fund raise for our HLF bid

or you can send a cheque payable to
Avon Industrial Buildings Trust to:
The Treasurer, Thatched Wells, Duckhole, Thornbury, BS35 1LD.

Leaflet giving information, asking for support and how to make a donation

Progress in 2016

Look at the reports page to see the summaries of the results of inspections of the bridge. Updated 11 January 2016

Photos of Progress in 2016

September 2016

Doors Open Day Photos of Progress in September 2016

August 2016

Tasks Photos of Progress in August 2016

July 2016

Tasks Photos of Progress in July 2016

June 2016

Tasks Photos of Progress in June 2016

May 2016

Tasks

Photos of Progress in May 2016

April 2016

First volunteer day of the year spent tidying up, continuing with renewal of timber stops, measuring the turntable rotor wheels and checking tie-rods and cast iron end fittings.

We had a brilliant day as far as weather was concerned, and a pretty good day as far as further investigation and work was concerned. Amongst other things, we were able to get good measurements on the rotor wheels for the turntable and additionally we were able to peer into the void of the top flange on the southern edge beam at a couple of locations.

turntable rotor wheels
The diameter of the wheels was calculated from the dimension around the perimeter, measured a couple of times with a thin flexible wire wrapped around the circumference of the rim. As you will see, the wheel in the NW quadrant was significantly smaller than the other three wheels and the flange on this wheel was also very damaged – in places non-existent. Since the perimeter dimensions were taken in two places (near the inner and outer edges of the rim – not on the flange), this showed that the rim is quite level. The slight exception was on the wheel in the SW quadrant where the perimeter near the flange was slightly less than the perimeter near the edge, albeit the difference in perimeter was only 10mm.

The original Brunel drawing, dated 1849, showed wheels at 2’-6” diameter, but there is correspondence from Brereton, the Resident Engineer, to say that this was to be altered to 2’-3” (it is thought). The latter is quite close to the largest diameter deduced from yesterday’s measurements (681mm = 26.81”) and, assuming that the wheels were all cast from the same mould, then this suggests little wear on three of the wheels and more significant wear on the wheel in the NW quadrant – which was quite damaged in any case.

Hopefully, this will help us taking forward options for repair of the wheels and the turntable beam.

Assuming that the wheels were originally cast to 27 inches diameter, and that we still have the original wheels, the minimum loss of diameter is 1/8 inch and the maximum well over 1 inch (on the NW wheel). Clearly scuffing has caused wear over a long period probably due to one or more of the following:

If the proposed gear/pin-rack drive is to stand any chance of working we shall need to get everything well aligned so as to reduce the torque required to rotate the structure. Quite a challenge!

tie-rods
It is reassuring to see the relatively good condition of the tie-rods and cast iron end fittings, and if they are all like this we probably will be able to extract one or more wedge and re-tension the tie-rod on the south side. It appears from these that at least the end tie is in fair condition as is the internal surface of the iron – as far as we can see.

Photos of Progress in April 2016

February 2016

Work by the professionals continued

  • Photos of Progress in February 2016

    January 2016

    Work by the professionals starting
    • Plate thickness-measurement works were tendered and three competitive prices were received. As they submitted the lowest tender, we checked with Wallis Conservation Ltd (Dorothea) that they have allowed for the necessary H and S documentation, and temporary works, and that they can complete the investigative work by mid February, all of which they confirm. Dorothea have now started on site and have made good progress removing plates.
    • Historic England received two credible tenders for the hydraulic study. The lower one was from Ken Grubb Associates who designed the existing hydraulic systems that power the entrance lock gates and paddles. HE have instructed KGAL, and confirm that the cost does not come out of our £14K grant for the current investigative work. Bob hopes to get the ground excavations contractor started on site on monday 1st February.

    Photos of Progress in 2016


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