The Grade 2 listed Admiralty Pier at Dover Harbour was constructed in the 1870s with the intention of stopping the long standing issue of shingle shifting eastwards, the pier also had a railway laid along its length to allow various cross channel services, including the Golden Arrow, to draw up alongside the cruise ships.
As part of the regeneration of the Dover Harbour, Kier Construction Limited were awarded the refurbishment project of the Admiralty Pier. Over 500m of high level concrete slab edge had severely corroded due to the marine environment attacking both the mass concrete and horizontal steel sheet piles supporting the cantilevered walkway. Their contract was to reduce the slab edge in width, carry out repairs and fit new handrails.
Following a successful history of completed projects with Kier Construction, we were awarded the sub-contract to carry out both structural and cosmetic concrete repairs.
Once the demolition sub-contractor had completed the removal of a section of slab edge, we prepared the substrate by scabbling and grinding. Due to the severe marine environment that the finished works were to withstand, the prepared surfaces were treated with a Fosroc epoxy primer for additional protection.
Timber forms were then clamped into place and reinstatement carried out with Fosroc Renderoc HB, a traditional polymer modified hand placed repair mortar.
To complete the our works, an anticarbonation coating was applied to the repaired slab edge and expansion joints installed and sealed allowing the handrail sub-contractor to follow on with his works.
Despite the challenges encountered with the spring time weather and wash from the passing cruise ships, the works were satisfactorily completed within the contract programme.
We initially carried out site investigation, testing and laboratory analysis of concrete samples to 3 bridges carrying the A31 over a bridleway and 2 sections of the River Wey at Farnham for Surrey County Council. Following this a Specification and Bill of Quantities was prepared for the Client.
The conclusion of the investigation work was that all 3 bridges required concrete repair and protective coatings and strengthening was required to one of them to meet the 40 tonne vehicle loading standards.
The following year we were awarded the contract, through the client’s term contractor Ringway Highway Services, to carry out the full proposals that included design & installation of carbon fibre composite plate bonding strengthening.
A full birdcage scaffold was used to access the soffits and walls of the bridleway bridge whilst maintaining access below for pedestrians and horses.
Concrete repairs were carried out using polymer-modified hand placed repair mortars and flowable concrete supplied by Sika Ltd. Coatings ranging from a clear anticarbonation to a siloxane water repellent impregnation were applied where appropriate.
The second bridge had limited headroom and scaffold was not appropriate. Here the work was carried out by operatives wearing waders and using small scaffold storage platforms to keep plant and materials clear of the water.
Strengthening to the third bridge was carried out on the soffits using Sika CarboDur plates. Tony Gee & Partners carried out design on our behalf working to the Client’s brief.
The concrete soffit was prepared by light scabbling and over 300m CarboDur S1012 plates were cut to length by guillotine. Epoxy resin was applied to both the prepared concrete surfaces and to the plates by drawing them through a gauge box. The plates were then offered up by hand to the soffit and finished by a light roller extruding excess resin.
This method of strengthening permitted traffic to continue to use the dual carriageway above giving minimal disruption to the traffic.
The 60 Charlotte Street project in west London consisted of the refurbishment of the existing reinforced concrete framed two-storey podium block and seven-storey tower block.
The main contract works involved a full strip out of the existing finishes and plant, construction of additional floors at podium and roof levels, structural alterations to the building, new cladding and glazing, roofing, M & E works and finally fitting out.
We were awarded the structural alterations package by Galliford Try which included: –
Consideration was given to the use of composites; however, this method was proven not to be appropriate in this situation.
In order to progress early procurement of the steelwork we removed the existing finishes to establish the structural dimensions. Then whilst our sub-contractor detailed and fabricated the steelwork we carried out repairs to redundant service holes, structural investigation sampling and demolished areas were carried out using polymer modified mortars and a flowable micro concrete.
The need for new steelwork was twofold. Firstly slabs were strengthened and dry packed with shrink compensating grout prior to removal of walls and upstands by Galliford Try. This in turn allowed them to proceed with the extension to the podium block and demolition of walls and slab edge upstands.
Secondly new risers were required for the full height of the tower. Prior to cutting the holes new trimmer steel was erected and subsequently dry packed. We employed scaffolding and diamond drilling subcontractors for crash decks and for forming the holes. Cut edges to the slab were repaired using a polymer-modified mortar.
Over 40 tonnes of steelwork were erected with 25 tonnes of grout, concrete and mortar used over a 20-week programme.