Stourbridge Borough Council

The name of the Borough and it’s close connection with the County of Worcester are symbolized by the bridge and the two pears,
whilst the fleece and the chain suspending it are typical of the skin and leather dressing and chain cable industries, carried on in the Borough. The motto, “One Heart, One Way” expresses the “singleness of mind and purpose” animating the members of the town council. Built in the mid 1980’s The Crown Shopping Centre in Stourbridge is currently undergoing a major £50m refurbishment. Set in the floor slab of the main entrance was a beautiful mosaic depicting the coat of arms of Stourbridge and its heraldic motto “One Heart, One Way”.

In the early stages of the project the main contractor, Bowmer and Kirkland was instructed by the client to remove the delicate tiled mosaic carefully for relocation to the new build.

EMDD-UNIVERSAL, a sub contractor to Bowmer and Kirkland for over 30 years, was called in to give advice on the safest way to release the mosaic.A preliminary site visit to drill test cores showed that the mosaic was inlaid in a 75mm screed over a 200mm thick suspended slab. When viewed from below, it could be seen that the mosaic was positioned directly above two intersecting beams with no clear interface between them and the mosaic bearing slab. It became clear that to remove the mosaic without damage, it needed to remain attached to the structural slab.

Faced with the difficult task of separating the slab from the beams, EMDD-UNIVERSAL devised a method of extracting the mosaic using a combination of stitch drilling, wire sawing and floor sawing. The first process involved diamond stitch drilling a series of overlapping holes through the floor slab to expose the tops of the beams and to provide access for the wire sawing process. Stage two involved carrying out a horizontal wire saw cut to separate the reinforced concrete slab from the structural beams.

As the basement was 6m below it was decided that the safest option was to secure the wire saw to the top of the slab and utilise a series of pulleys attached to the underside of the slab and structural beams to guide the wire during the cutting process.

As the controls of the wire saw would be on top of the slab the operative would be in effect working blind, therefore the pulleys had to be positioned millimeter perfect to ensure a smooth cutting process. Throughout the cutting process a technician remained beneath the slab, at a safe distance, to observe the cutting, keeping in contact with the operator by use of two way radios. Once the section of slab had been released from the structural beam, the next stage of the operation involved releasing and lifting the mosaic and floor slab from the surrounding area.

To separate the mosaic from the surrounding floor slab a perimeter saw cut was required through the slab beyond the perimeter of the mosaic. Prior to the saw cutting, four mechanical lifting bolts were inserted and two mobile gantries with electric hoists were used to take the weight. Following the perimeter separation cut, the released section of slab containing the mosaic was then carefully lifted from its location and placed aside.