Footfall assessment - introduction

The current architectural trends tend to produce more sleek and slender designs, contrasting with heavy structures of the past. This is possible thanks to increased design efficiency, allowing the utilization of stronger materials in design considerations. Consequently, this results in lighter structures being built, which is often accompanied by the reduction in structural stiffness and damping. Such structures can struggle to satisfy the vibration serviceability limit state criteria for human occupancy. Therefore, more accurate methods of assessing human induced vibrations on floors are required.

While earlier versions of Tekla Structural Designer included options to run simplified floor vibration checks to either the AISC DG11 or the SCI P354 design guide, the above mentioned need for more accurate methods has resulted in the introduction of a rigorous footfall assessment. This new approach involves the creation and modal analysis of floor analysis models for dedicated footfall mass combinations. The resulting workflow consists of two parts:

Prediction of the structural response in terms of acceleration and/or velocity.
Footfall checks to evaluate the limiting criteria.

The new approach can be performed to either the SCI P354, CCIP-016 or AISC DG11 design guide. While it offers a comprehensive set of options for advanced users, the workflow it adopts is easy to follow.

Note: The simplified floor vibration checks to DG11 and SCI P354 have both been retained, should you still want to make use of them.

Relevant design guides and codes

The following design guides and codes provide resources relevant to footfall analysis:

SCI P354: Design of Floors for Vibration: A New Approach by the Steel Construction Institute ^{(Ref. 1)}
AISC DG11: Vibrations of Steel-Framed Structural Systems Due to Human Activity by the American Institute of Steel Construction ^{(Ref. 2)}
CCIP-016: A Design Guide for Footfall Induced Vibration of Structures by the Concrete Centre ^{(Ref. 3)}
BS 6472-1:2008: Guide to evaluation of human exposure to vibration in buildings. Vibration sources other than blasting ^{(Ref. 4)}
ISO 10137:2007: Bases for design of structures - Serviceability of buildings and walkways against vibrations ^{(Ref.
5)}

The design guides specify analysis methods, whereas the two codes, BS 6472-1:2008 and ISO 10137:2007, focus on defining the limiting criteria.