Alliance Leisure worked with ISG to build a 25m swimming pool and spa within the existing structure of a sports hall. We talk to Mark Gibson, ISG site manager, about this impressive feat of construction engineering.
Q. How did you come to be involved in the scheme?
Alliance Leisure appointed us as principle build contractor to refurbish and extend Monmouth Leisure Centre in South Wales. The £7.4m project was the 18th scheme that Alliance Leisure had awarded us through the UK Leisure Framework. It has certainly been one of the most complicated, but anything is possible with the right team and procurement approach.
Q. What was the brief?
Monmouthshire County Council wanted to future-proof the centre’s facilities while meeting demand in under-represented markets in the area such as health and wellbeing and children’s play. The project would provide a raft of new facilities including a new gym, studios, a toning suite, children’s play area and café. The town had been without a public pool for some years, so the council also wanted the development to include a 25m pool and a spa.
The leisure centre shares its site and some of its facilities with Monmouth Comprehensive School. At the time of the redevelopment, a new home for the school was being built to the left of the leisure centre. With the existing school sitting to the right of the centre, the only place to put the pool was in the leisure centre’s sports hall.
The combination of the location of the leisure centre between the old and new schools, just one access road into the site and 2,000 pupils passing the live construction site every hour made the logistics of the project hugely challenging. We always knew this was going to be a difficult project, but logistically it was more challenging than projects I have run in central London.
Before work could begin on the pool, we had to erect a temporary sports hall to accommodate the school and community while the project was ongoing. We built temporary facilities for the London 2012 Olympics, so were able to construct a high spec, four-court hall in six weeks that was bigger and better than its permanent predecessor.
Q. How did you overcome the challenges?
We worked with Alliance Leisure to develop innovative solutions to a number of challenges caused by the logistical constraints of the site. A single narrow strip – 1.5m at its thinnest point – provided the only access to the hall. We had to remove a section of the elevation to get the necessary piling equipment and plant machinery into the building to facilitate the work.
We stripped the building back to its shell and treated with spray-on insultation to protect and seal the hall and prevent any impact onto the adjoining dry site.
Monmouth has soft ground as well as a high water table, which called for some innovative temporary works solutions and creative piling designs to support the new swimming pool.
The existing concrete slab in the sports hall needed to be broken out before excavation work could commence. However, traditional temporary works solutions could not be implemented due to logistical constraints. An innovative solution was developed to install a king-post wall to form a u-shape around the deep end of the pool. I-beam posts were driven into the bedrock at 1.2m intervals and then railway sleepers were slotted between the beams on top of one another to form a sacrificial support structure. Another bespoke element saw the use of steel tube piles instead of CFA piles. This solution minimised noise and vibration and reduced the volume of arisings produced.
We also used a sprayed concrete system to cast the slab and walls of the pool. Rejecting a typical formwork solution, again due to logistical constraints and to provide a quicker application, we used a specialist lightweight concrete mix. This unorthodox approach delivered significant time savings – with the entire pool completed within a week and designed, built and tested to BS EN 1992-3:2006 standards.
Q. What made this a successful project?
Construction is not about putting blocks on top of each other; it’s about creativity, innovation and changing perceptions. Thanks to our successful partnership with Alliance Leisure, we were able to take a pragmatic approach to the project, value engineering as and when necessary. This included redesigning the spa area to make better use of the space and include a treatment room. You can only make these types of improvements on projects where you have such close collaboration.
To view more details on the Monmouth development visit our case studies page here