FLOOD DEFENCE SOLUTIONS: HOW PRECAST AND MASONRY SOLUTIONS CAN KEEP CONSTRUCTION PROGRAMMES ON SCHEDULE, WHATEVER THE CLIMATE
With over five million homes in the UK estimated to be at risk of flooding and coastal erosion, the government’s announcement in July that it would be investing a record £5.2 billion to tackle the issue will have come as welcome relief for many.
The strategy – set out in the Environment Agency’s National Flood and Coastal Erosion Risk Management Strategy for England, published on the same day as the announcement – is for a combination of long-term delivery objectives, over a period of 10-30 years, alongside ‘shorter term, practical measures risk management companies should take when working with partners and communities’.
Among the short-term measures is £170 million allocated to begin 22 ‘shovel-ready’ schemes. Work is expected to start on these sites this year and into 2021. Many of the sites indicated are in built-up residential or business areas, throwing up numerous challenges for engineers and agencies in terms of keeping scheduling and disruption under control, in addition to producing an aesthetically pleasing scheme.
Flood defence schemes in challenging urban locations
Facing the challenges of a constricted city centre location was the Derby City Flood Defence projects that Forterra worked on in 2019. Access to and from the site was difficult for construction traffic, which, in turn, would affect the ability of local people to move in and around the area. It was important, therefore, to find a solution that would cause minimal disruption while also delivering a finished result that would complement the surrounding area.
Forterra’s Quickwall, a new and innovative prefabricated masonry walling system, proved to be the ideal solution.
Prefabricated masonry walling systems
Prefacbricated masonry walling systems such as Quickwall offer many unique time, safety, quality and cost benefits for construction projects, including:
- Off-site manufacture of structural and aesthetic brick walls, using full bricks and a specialist bonding mortar
- Quick and easy production methods
- Installation up to 12 times faster than traditional bricklaying
- No requirement for skilled bricklayers
Time-saving benefits of prefabricated flood defence solutions
In the instance of the Derby City Flood Defence, the use of Quickwall contributed to a six-week time saving against the project’s original construction programme despite adverse weather conditions. It’s an example of how prefabricated masonry walling systems can bring benefits not only to flood defence schemes, but also to a variety of other civil engineering applications, such as retaining walls and transport infrastructure, which cannot easily be accessed by bricklayers.
Similarly, when Forterra’s Bison Precast was called upon to provide a speedy resolution to the repair of the Dawlish Sea Defences – after 90m of seawall was breached severing a key rail link to the south west – 96 L-shaped bespoke retaining wall and 152 profiled precast seawall units were manufactured at its Somercotes factory before being transported down to the Devon coast. It’s a great example of how a Design for Manufacture and Assembly (DfMA) approach can improve speed of turnaround and the ability to produce components of consistent quality thanks to offsite production under factory conditions. For the Dawlish Sea Defences project, it helped to minimise disruption in the area and contributed to the reopening of the railway ahead of schedule.
Converting in-situ concrete designs into precast concrete solutions
By adopting a Design for Manufacture and Assembly (DfMA) approach, many in-situ concrete designs can be converted into cost effective precast concrete solutions. This offers numerous advantages for flood defence schemes as components can be manufactured to approved designs and held in stock to be called off as needed.
This offers incredible flexibility in terms of design and aesthetic finish, which includes brick as well as a choice of textured concrete. This ensures schemes can be readily adapted in keeping with the local environment.
Labour-saving benefits of prefabricated flood defence solutions
As with any construction scheme, one of the key issues for agencies and contractors to manage is health and safety. Prefabricated flood defence solutions such as those offered by Forterra help to keep workers safe by minimising labour, particularly wet trades, on site. This is important at any time, but especially so in the current climate when social distancing measures are in place.
Read more about Quickwall prefabricated masonry walling for flood defence
Read more about Bison Precast bespoke products for flood defence