Middleborough Multi Storey Car Park – Makers Construction
Middleborough Multi Storey Car Park
Triflex DeckDefence / Triflex DeckFloor
Middleborough Multi-Storey Car Park, Colchester was built in 1979 as part of the Octagon Office Block development. The Car Park is a five-storey reinforced concrete structure designed and built by “British Lift Slab” as a design and build sub-contract using the lift slab technique. Many car parks such as this have a history of early deterioration and structural defects due to both poor design and construction. The car park comprises of a five-storey reinforced concrete structure constructed using the lift slap form of construction for levels 1 – 4 onto precast columns with the ground level 0 cast in-situ and supported by 54 precast concrete columns per level.
Throughout the car park was evidence of deterioration and defects primarily due to poor design and construction. The top deck waterproof coating was debonding and cracking showing signs of wear and tear allowing water penetration to the levels below through cracks in the soffits and leaking gulley’s. Throughout the whole car park were 54 columns on each level, all of which were at risk of causing a punch and shear issue where the columns start to penetrate the slab above and causing cracks within the soffit slab. If left un-remedied this could result in closure of the car park and at worst case collapse. The intermediate decks had never been coated and were suffering from Chloride induced corrosion. The internal inter-level containment barriers were wooden and no longer fit for purpose. A mix of Triflex Deck Defence and Triflex DeckFloor Systems were chosen as the best remedial installation for the car park. This mix of Triflex systems was targeted to achieve the optimal system performance on the top deck and lower decks.
On the top deck, the old existing waterproof membrane was removed, and concrete repairs to the slab were carried out. Deck cracks were banded and Triflex Deckfloor installed along with newly introduced pathfinding and pedestrian walkways installed. Triflex DeckFloor was chosen for this refurbishment as it is tough and durable, with the installation totalling 2500m2. This ensures that Middleborough Car Park is protected from water ingress, chlorides (from road salts) and chemical attack; with the DeckFloor System able to withstand both long term heavy traffic and extremes of weather. Therefore, Triflex DeckFloor was the perfect solution for the open-air top deck of Middleborough MSCP.
The eight lower decks were suffering from shrinkage cracks and also radiating cracking from columns, some of which had previous repair works of resin injection. To mitigate against this issue, all cracks were banded and epoxy primer Triflex 116 DeckDefence filled system applied to the decks, totalling 10,500m2. Quartz was cast into the primer base layer and sealed with Triflex DeckDefence Sealcoat in the clients chosen colour pallet. This durable solution protects decks and ramps from chemicals, chloride contamination and carbon dioxide ingress, satisfies slip resistance requirements and visually improves and enhances the parking environment. Triflex DeckDefence is an ideal solution for enclosed car park environments as it is solvent free and does not require ventilation for installation.
Due to each bay being numbered, there was a large amount of signage involved. This had to be carefully planned and scheduled accounting for the time and labour resources required to not impact programme length. New mapping and marking out of the car park were also required throughout, to incorporate new dedicated pedestrian walkways which were installed on all levels with a walking person logo to demonstrate using Triflex Preccoline. Templates were designed for numbers, speed limits, disabled bay, and EV Charging bays.
Within the M&E package, EV Charging Units 4x Twin 11Kw 3 phases were installed for 8 parking bays. These are fast charging and provide a full charge within 3 hours, operated by Charge Vision App which is part of Polar Public charging network which has over 7,000 charge points throughout the UK. As highlighted previously, these bays were clearly marked and signalled using Triflex Preccoline.
Middleborough Car Park was a live site, which made the construction process difficult. Every parking bay was numbered, and bays were allocated to individuals and offices of the Council and also to offices of the Octagon, so a register of bays and allocated delegate list needed to be maintained. This was to ensure a smooth and efficient parking experience for those who would be affected when refurbishment of their allocated bay would be in progress, but also notification of an alternative allocation of a temporary bay. Only 45 bays were released at any-one time which made the refurbishment scheduled into 11 phases!
During- The existing, old solid mahogany signal barriers had run their course and were removed in their entirety. These were replaced with a bespoke system consisting of specially designed spring-loaded galvanised steel posts. The design of the posts is to take an impact of up to 150kn with deformation of the slab and absorbing the energy.
As the signal barriers were made of solid mahogany the project was desperate to ensure these were not just merely skipped but repurposed. A local appeal went out and the Client was contacted by a local man who had over many years supported some local children’s charities by making wooden climbing frames. From the car park, 3 tonnes of timber were donated and constructed into climbing frames. Now some of the Middleborough Car Park will have an extended life across the Colchester Region and benefit local children. The typical climbing frame can cost between £2,000 & £4,000 for local charities so we are delighted that these materials will make such a big difference.
During the works, the decks were fully investigated including a half-cell survey which showed that 400m2 of deck required installation of ICCP (Impressed Current Cathodic Protection) anode system which will be remotely monitored by CPT (Concrete Preservation Technologies Ltd). The ICCP system requires holes to be drilled in the deck 450 centres apart and approx. 100mm in depth. Chases are cut between holes to form a series link pattern. The anodes are placed into the holes, inspected and tested and then buried in conductive mortar. Throughout this project a combined quantity of over 5,000 anodes were installed. Thus, demonstrating the huge scale of the corrosion in the reinforcement and the mammoth task of ensuring this was remediated and did not negatively impact the car park into the future.
Furthermore, the scale and extent of this full car park refurbishment is shown in the amount of different works completed to bring the car park back up to a quality standard. The extensive 42-week programme indicates that this project was highly detailed and required skilled workmanship from a vast number of trades for success. For example, 1296 fail safe brackets were installed to every column to combat and counteract the punch and shear issues. Further works included a new bike hub, a full electrical infrastructure wire upgrade and a full external jet wash clean.
This contract was in operation during Covid, creating difficulties. Space and testing formed high priorities in order to maintain 2 metre distance. A specialist welfare unit was set up in the Octagon which provide ideal space for setting up a testing centre for daily tests. This allowed the covid risk to be significantly decreased on site and ensured the safety of all site personnel and operatives. The separation of the workforce over the whole project, from toilet breaks to mealtimes meant precise planning and co-ordination were required.
As well as full monitoring stations a “Wellness Room” was also constructed. With many staff and workers working away from families during this time a breakout room was created with the help of the client. This provided a private space where issues could be discussed safely on a one-to-one basis and individual mental health be observed. This forward-thinking approach put the wellbeing of staff first and enabled them to talk about and overcome any issues or troubles.