Visual Control Tower, Heathrow Terminal 5, London, United Kingdom

Building dynamics involve the assessment of the dynamic properties of buildings in terms of mass, stiffness and natural frequencies and their response to dynamic excitations.

The Visual Control Tower (VCR) of Heathrow Terminal 5, London, United Kingdom is a slender 80m-high structure intended to replace the old airport control tower. The control tower being very slender was found to be quite susceptible to vibrations due to wind-excitations due to a fundamental natural frequency of only about 0.3Hz. Due to other architectural constraints, it was proposed that prestressed cables be used in order to increase the natural frequencies of the structure. Damping systems were then proposed for the main structure in the form of an active mass damper system (AMD) and explicit hydraulic dampers to reduce induced cable vibrations.

A complex modal analysis was performed on an existing MSC.NASTRAN finite element model of the tower. Optimum damping parameters for a tuned mass damper (TMD) was also established in place of the AMD. The result of the analyses was the design of a TMD that effectively reduced the wind-induced accelerations of the structure to acceptable vibrational limits for the occupiers of the building.

Note project is a previous principal work experience at Arup.