Concepts & Designs
The Cactus Towers, Copenhagen, Denmark. (Source: BIG)
SENSORS IN CONCRETE:
New technology to improve efficiency and minimise material waste
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ontrol of concrete strength and maturity in largescale projects has traditionally been recorded and measured manually. Nowadays, there are new technologies that allow builders to melt sensors directly into the concrete whereby when connected to a transmitter show continuous data on the material’s temperatures, sending the data wirelessly to the cloud platform. The software then automatically calculates maturity and strength based on historical data, so the concrete mix and strength development process can be followed from any device and in real-time. These sensors, based on 0G technology from Sigfox – one of the main IoT (Internet of Things) operators in the world – have facilitated the construction of one of the most innovative architectural projects in Europe, the Cactus Towers (Kaktustårnene) in Copenhagen, helping calculate the exact moment to remove the formwork that shapes its characteristic façade. Expected to be completed by spring 2022, the Cactus Towers have been designed as a hotel and a residence for youths in central Copenhagen, Denmark. The towers stand at a height of 60m and 80m respectively, and are shaped by hexagonal cores. The 21,000sqm hotel consists of 1,250 rooms spread over the two
36 January-February 2022 | www.b-i.biz
towers, which also house 500 ‘youth rooms’ averaging 30sqm in size with modern aesthetics. The project has a technical complexity that few buildings have as each floor is rotated in a different axis and their complicated forms create displaced balconies and cornered façades. In terms of materials, special attention is paid to the concrete formwork to achieve a solid foundation, which is an additional challenge since large structures with many floors normally require cooling to guarantee product quality. Therefore, the monitoring of the condition of the concrete plays a fundamental role as it is essential to give the towers their twisted and very particular shape. In the case of the Cactus Towers, the builders used a solution by Maturix that consists of a comprehensive tool to control the strength of the concrete in a much more efficient way. With thermocouples fused into the structure, the concrete temperature can be accessed in near real-time and the data collected are sent wirelessly to the cloud. Maturix has a software to calculate maturity and resistance based on historical data, which is an advantage when making adjustments in project management. Given the complexity of the project and with many subcontractors involved, it is a plus in terms of organization and time measurement. The second part that has made the project possible, together
