High level synopsis:
Real time monitoring and alerts for critical path concrete works on a major landmark construction project.
Extreme loading conditions, critical path concrete strength and the need for multiple on site actions meant accurate concrete strength data was absolutely critical to successful and on time delivery.
The Converge system successfully captured immense variations in curing times of up to 100% which were magnified by harsh weather
Background: A landmark project
Battersea Power Station is a Grade II listed building built in 1941 and one of the most iconic landmarks in London. It was decommissioned in 1983 and for 35 years has stood derelict on the South Bank.
In 2013, a major restoration project began to transform the derelict site into a major new mixed-use development. This makes Battersea Power Station Europe’s largest urban regeneration scheme and the largest single private building contract awarded in the UK.
Mace and their construction partner PCE Limited applied a unique hybrid method of construction combining precast concrete elements with in-situ pours and steelwork.
Methodology: Modern, efficient construction
The unique hybrid construction method used at Battersea Power Station marries structural precast concrete, in situ concrete and steelwork to deliver modern structures otherwise impossible to construct applying traditional building methods such reinforced concrete, with comparatively higher productivity, at a lower relative cost.
This innovative hybrid method of construction requires in-situ concrete “stitching” in between precast concrete planks, as well as topper for lattice planks. The precast planks themselves arrive on site at full strength (50MPA), so 90% of the concrete being installed is already at full strength. This means that the in-situ concrete stitching sits on the programme’s critical path.
Client challenge: Critical path concrete and extreme loading
The design phase of the project involved extensive planning and tailoring to account for the complexity of the project and delivery within the programme timeframe. Despite this, project speed and floor cycles still remained directly affected by the rate of curing of concrete stitching.
Lattice planks and the formwork surrounding precast propping required cracking and re-propping at 15MPa and 25MPa respectively. Unlike traditional in-site construction methodologies which allow for a gradual distribution of load, the precast columns absorb full load when propping is removed and tightened.
Extreme loading combined with the critical path nature of in situ concrete meant that understanding strength gain accurately was of heightened importance.
Value and benefits:
The works were carried out over the winter months, between 2018-2019, during adversely poor weather conditions. Cold temperatures, heavy rain, and even snowfall meant that the in-situ pours were curing much slower than usual. Curing times went from 3 days to about 5.5 days to achieve 25MPa. The converge system was able to detect these slower curing times, allowing for safe work, without risking cracking or detrimental effects to the structure due to early removal of propping. This information allowed engineers and planners to accommodate the wide varying curing times by reprogramming their sequence of works, thereby opening up additional work fronts.
Collaborative remote working
The Converge system allowed for engineers to oversee projects from a distance, without always being physically present on site. On occasion, senior Engineers were able to oversee multiple projects and, replying on Converge’s succinct, real time data and reports to communicate curing data to their designer and client, keeping all parties in the loop.