Brooklands Racetrack


Brooklands

Brooklands is a disused motor racing circuit and airfield just 20 miles south west of London near Weybridge.

It now houses the Brooklands Museum and Mercedes World with many of the old buildings and track reinstated to their former glory.

It was the brainchild of a wealthy landowner Hugh Fortesque Locke-King who, in 1906 during a European tour, decided that Britain needed its own test track if the new motor industry was to compete with the Europeans,

Work commenced in 1906 and in June 1907 the world’s first purpose built motor racing circuit was opened.

Due to the difficulty at the time of laying tar macadam on the steep banks, the track construction consisted of gravel overlaid with concrete in order for the steep banks to be cast in shuttered sections.

In 1937 the Road Racing Circuit, designed by Malcolm Campbell and built of similar construction, was added.

At the outbreak of the Second World War in 1939 the whole site was devoted to the production of warplanes and the circuit’s condition deteriorated during this period. It was finally sold to Vickers-Armstrong for aircraft production and in 1987 it became Brooklands Museum.

The Malcolm Campbell Circuit is classed as a scheduled monument and 100 years after Brooklands opened, we were awarded the contract to repair parts of the concrete track.

Gifford and Partners produced the ‘Specification for Works in Relation to Scheduled Monuments’, which included a performance specification for the concrete based on the original construction. As the aggregate used in 1937 was not available from the original source a similar alternative flint material was found in a quarry in Norfolk. Our concrete technician was then able to design the mix to match that of 1937.

Defective concrete was removed by electric hand breakers and edges square cut prior to the installation of a DPC, spacers and mesh. Due to the small quantities required each day and limitations imposed on the access to the track, site batching was considered the most economical option. Once cast, the repairs were cured with polythene sheeting in accordance with the specification.

Barbican Estate, City of London


Barbican Estate

The Barbican Estate, built on a 35 acre site between the mid 60’s and 70’s, is a fine example of British Brutalist Architecture with a wide range of exposed aggregate concrete finishes.  Surrounding the three concrete residential tower blocks, maisonettes and mews are the Museum of London, The Barbican Arts Centre, Guildhall School of Music and Drama, City of London School for Girls and Barbican Library all set amongst lakes, elevated walkways and gardens.

Due to the age of the structures and reports of a number of visible defects to the concrete, we were awarded the contract to survey the condition of the external concrete facades of the 3 tower blocks by abseil technique. These consisted of visual inspection, hammer testing, carbonation depth and cover meter survey, chloride analysis, half-cell and resistivity tests followed by presentation of an interpretive report and recommendations.

Due to the risk of falling failed concrete, a scaffold protection platform and exclusion zones were provided at the base of each tower whilst the surveys were carried out.

Whilst the extent of defects was being established from the survey and taking advantage of the protection already in place at ground level, we successfully negotiated the next phase of the concrete repair works, completing repairs to within 20mm of the final finish with a Remmers high build polymer modified repair mortar.

In the meantime trials were carried out to establish a finishing material that would be both technically acceptable and also satisfy the requirements of English Heritage and Corporation of London’s Planning Department.

Upon agreement of the specification for the finishes of the repairs, consisting of a colour matched Remmers Restoration, the final phase of the repairs was carried out by abseil techniques and by working from the balconies.

Following the success of the survey and repairs to the 3 tower blocks, we have been awarded a number of further condition survey and repair projects throughout the Barbican Estate.

Allington Sluice


Allington Sluice

Built in the 1930’s, the Allington sluice lock gate is the last on the Medway before it becomes tidal. During 2010 the sluice underwent a major refurbishment including new gates, lifting gear and gantry, repairs to the concrete structure, a new fish pass and new disabled access ramps.

Although the sluice is not listed, due to its location adjacent to the Museum of Kent Life, the Environment Agency took a very keen interest in the structure and the refurbishment works.  Any areas of concrete that had spalled due to   seventy years of weathering were therefore required to be repaired sympathetically to match the existing concrete finishes.

We were employed by the Main Contractor, Jacksons Civil Engineering, to undertake  initially trial samples in order to create a repair material that could be applied over the polymer modified structural repairs.  This involved design of a range of mixes and bonding primers together with sourcing suitable sands, aggregates and cements.

Following the successful completion of the trials, we were awarded the contract for both structural and cosmetic repairs that were carried out in 3 phases throughout the year.

Upon agreement of the extent of repairs, defective concrete was broken out to expose the corroded reinforcement, which was then prepared and primed using a cementitious coating.  Where corrosion to the steel was excessive, additional reinforcement was fixed. Repairs were then carried out using a weber prebagged hand applied polymer modified repair mortar to within 15mm of the original profile.

Repairs were completed by priming with a weber epoxy resin and whilst tacky the application of the approved mix from the trials.  Surfaces were then abraded to remove laitance exposing the aggregate matrix to varying degrees. Where appropriate, a soot wash was applied to the finished repair to simulate the result of many years of weathering of the concrete.

Resin injection techniques using weber.tec EP resins were also used to repair cracks where there was no evidence of reinforcement corrosion.

Admiralty Pier, Dover


Admiralty Pier

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.

A31 Bridges


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.

60 Charlotte Street


60 Charlotte Street

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: –

  • Strengthening of existing slab edges
  • Filling of redundant voids to the floors
  • Concrete repairs to the structure
  • Forming new service risers with associated structural steelwork
  • Forming new openings in walls

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.