Footfall induced vibrations

Lately on one projects I faced with non-typical solution of walkways in a residential building. The solution is based on steel cantilever which supports prestressed walkway slabs as below. Steel box beam is suspended to wall above by Peikko SUMO shoe. (Fig. 1, 2)

As walkway can be susceptible to vibrations during walking or running it was decided to check how it behaves regarding this. What is more, steel cantilever is rather rare solution when it comes to walking routes. At the end I thought that I do not want to hang a table “do not run” or “max 5 people on pedestrian route” in a newly built residential building?;) (Fig. 3)

A footfall analysis in FEM Design was performed to check self excitation walking activities in a wide range of 1,5 – 4,5 Hz. The result was a map of acceleration which says about comfort of walking and tells us if the vibrations are acceptable or not. (Fig. 4)

Then representative points were chosen to create a spectrum of response curves in previously mentioned range of 1,5 – 4,5 Hz. (Fig. 5)

Final step was rhythmic excitation analysis to show if jumping in particular places can cause a damage.

#engineering #footfall #FEMDesign #comfort #precast #vibrations #modalanalysis #walking #fatigue