CASE STUDIES
Sutton Harbour Swing-bridge Bearing
A&T Services Ltd were engaged by Plymouth City Council to carry out the replacement of the pivot bearing in the swing-bridge that links the Barbican area of Plymouth to the National Marine Aquarium.
The bearing which is 1.5m in diameter and weighs approximately 1 tonne was supplied by SKF (UK) Ltd as a special one off manufactured item.
The refurbishment work included the installation of the bearing and the reinstatement of the hydraulic and electrical systems that control bridge movement. The work was completed to programme so that the bridge could be used by members of the public during the busy Easter and summer holiday periods.
Sutton Harbour Hydraulic Ring Main
The operation of the Sutton Lock is dependent upon four 30 tonne sector gates which are operated by large hydraulic rams. The hydraulic rams are powered from a central hydraulic unit and the oil is circulated in a stainless steel ring main.
A&T Services Ltd employed metallurgists from the University of Bath to examine the hydraulic pipework and identify the cause of a number of small leaks. Based partly on the outcome a decision was taken to replace the pipework, including the underwater sections that pass across the width of the lock.
The underwater pipework was the most challenging aspect of the project. Individual fabricated pipes which consisted of two 8m vertical sections and a 16m horizontal section welded into a U shape, pressure tested and craned into position with a large spreader beam for support. After being fixed in position they were pressure tested again to ensure no integrity was lost during the lifting operation.
A total of 300m of pipework was replaced over a period of several months in a carefully controlled way to cause no disruption to normal operations of the lock or marine facility.
Millpool Tower
A structural survey of the original water tower identified advanced levels of corrosion, such that the only viable course of action was to completely replace the tower.
The original method of construction meant that the steelwork and foundations had to be completely removed in order to create a clear space for the new tower.
A&T Services Ltd were appointed as principal contractors for the work which included design and construction of new foundations, structured steelwork, water pipework and the proper disposal of waste materials generated by the works.
The new tower is 3.5m long, 2.5m wide and 4.6m in height. It is situated in an exposed moorland location and recently passed the tests posed by storms Ciara and Dennis.
Wheal Martyn Waterwheel Restoration
This overshot waterwheel is located in the Wheal Martyn Museum and Country Park at Carthew. It is 18 feet (5.49m) in diameter with working flat rods and cables which drive a slurry pump.
The wheel has cast iron rims and hub, wooden buckets and flat steel spokes.
The slurry pump and counterbalance boxes were made safe, to allow the flat rods to be disconnected such that the wheel could be rotated to allow it to be partially dismantled in sections.
Careful work allowed the main wooden components to be replaced, metal components to be cleaned and repainted, and for the restoration to be completed using appropriate materials.
The wheel is regarded as being of high significance. Located within an English Heritage site, it is a rare working example of a vanished but once commonplace technology.
