Leading UK concrete drilling and wire sawing engineering firm Holemasters has completed a challenging and specialised high level diamond wire sawing operation as contracted by Merseylink Civil Contractor Joint Venture. This was carried out as part of a key phase of the Mersey Gateway Bridge construction.
In autumn of this year
The design of the bridge is a cable-stayed structure with three pylons and a main bridge deck constructed from reinforced concrete.
Wire Cutting Concrete Pads
Holemasters was contracted to wire cut temporary concrete pads which were situated between the bridge deck and hammerhead at the North and South pylons. This would provide clearance to enable the deck to rest on its permanent bearings.
David Bailie, managing director of Holemasters, explains; “The method we employed was to form two wire saw cuts through each of eight temporary concrete pads, four on each of the North and South pylons. The concrete pads themselves were approximately 4m² in plan, therefore we undertook a 4m² per wire saw cut.
“Access was extremely difficult. Not only were the pads 15 metres up from the road access level, but one face was at the edge of the pylon and the other three faces provided very little clearance. A fixed scaffolding was out of the question as it restricted access for the main contractors’ other operations, and would have taken too much time to erect.
“Despite all of these challenges we had to meet a 24 hour per four pad pylon deadline as specified by the operational requirements.”
Holemasters successfully developed a method to park the wire saw machines at ground level and guide the diamond wire up the face of the pylon to the concrete pads. Mobile elevating work platforms were used to provide main access to the pads.
Due to the exposed location of the bridge, it was decided to use stainless steel expansion anchors rebated into the structure. These would provide the long-term durability demanded by the client.
“This contract brought with it a great deal of constraints which meant that detailed planning and co-ordination was required by all the parties involved”, David continues. “This effort was ultimately rewarded by the four pads on each pylon being cut within the required time constraints.
“Overall this has been a very rewarding project where we have used our creative expertise to provide a bespoke solution on time and on budget.”