Innovative Aspects of Composite Construction in the New Leadenhall Building

The Leadenhall Building will add a very distinctive shape to the London skyline. The external steel megaframe is one of the most visible parts of the building but the composite floors also include innovative features. The analysis for footfall vibration and the design of the floor beams for axial force used new approaches but the most significant innovation was the use of precast planks to span between the steel beams. The connection between the planks and the steel beams was developed partly in response to the specific challenges encountered on this project. Continuity between the planks for negative bending and in-plane shear was provided by the use of bars with threaded couplers and ducts cast into the planks. To transfer the shear between the slabs and the beams, a tab connection was used. A series of tests was carried out to establish the properties of the connection and validate the system. Results are presented in this paper.