Dynamic Analysis, Office Block, City of London

Our initial involvement with this project was designing a series of load spreading frames for heavy computer equipment, installed as part of a 10,000 square metre office fit out. As the project progressed the tenants became increasingly concerned about the apparent vibration of the office floors within this newly completed building. We were asked to carry out analysis of the floor structures to see if they complied with current design guidance, and also what the likely in-use performance would be like.

Our first task was to carry out a theoretical analysis of the dynamic performance of the floor structures. This required us to create a series of mathematical models representing the various possible modes of action, and assumed imposed loading. The behaviour of floor structures depends not only on the stiffness of beams and slabs, but also the degree of damping afforded by internal partitions and furniture; the amplitude of vibrations depending on how much ‘clutter’ there is to soak up the energy of vibrations.

The analysis results were then verified by in-situ tests on the floors. Vibrations were measured by floor sensors while people were asked to walk up and down.

Client/Project Management Litchfield Ltd