Many structural engineers face on a daily basis the challenge of designing composite steel floors that are safe, meet serviceably requirements and are efficient.
The design of a composite floor system is very often driven by meeting desired vibration characteristics, and complex footfall vibration analyses are required for this scope. Designing a floor system which minimize the use of steel and meets serviceability and vibration requirements is therefore a non-trivial exercise and the design process generally involves a large number of iterations.
With this consideration in mind, this study describes the results of a large number of frequency domain analyses performed to fully characterize the dynamic response of typical composite steel floors under footfall-induced vibrations. Results of this work, help identifying the influence of many different design variables on the vibration characteristics of typical composite floor systems. The design variables considered in this study include twenty-nine different floor spans, twenty-one different beam spacings, twenty-one different beam sections, two different levels of equivalent viscous damping and two different support conditions, for a total of more than fifty thousand different structural configurations.
Results of this work are plotted in easy to use design charts. The use of the charts is described here, together with their use for the determination of the vibration characteristic of existing floors. This paper constitutes a significant contribution towards the understating of the vibration characteristics of typical composite floor systems and it stands as an essential design tool for the determination of the most efficient floor system. Considerations on the minimum steel weight design and the minimum floor depth design meeting a desired vibration level are given in this work.
Results of this study also give an insight into the determination of when passive control devices, including Tuned Mass Dampers and viscoelastic devices, can be effectively used to reduce the vibration response of a composite floor within desired limits.