Composite steel and concrete floors account for over 65% of the multi-storey office market in the UK. The replacement of the traditional steel and concrete composite slabs with Cross Laminated Timber (CLT) panels is a logical step to both reduce the embodied carbon of the floor system and sequester carbon within the structure itself.

Working closely with WSP (who were ranked first in the Engineering News-Record 2022 list of top international design firms), Prof. Stephen Hicks is responsible for a comprehensive test programme on a new composite steel and CLT floor system at the School of Engineering. Unlike recent building projects using CLT, the steel beams within the new floor system have been designed to act compositely with CLT floor panels to achieve around a 40% saving in steel weight together with a saving in embodied carbon of nearly 25% compared to traditional composite steel and concrete floors.

Following a series of tests to investigate the performance of the shear connection between the steel and CLT panels, it is planned to load a 12 m span steel-CLT beam to destruction to study the behaviour of the system at full-scale and to evaluate the safety margins provided. It is intended that the design methodology will be disseminated to designers through the launch of a design guide at the Institution of Structural Engineers.