Vibration Analysis and Fatigue Assessment of Floors.Part II:Mechanical Equipment

Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims to develop an analysis methodology in order to assess the fatigue performance of steel-concrete composite floors,when subjected to vibrations induced by mechanical equipment.The studied structural model corresponds to a steel-concrete composite floor spanning 10 m by 10 m,with a total area of 100 m^(2).The numerical model developed for the dynamic analysis adopted the usual mesh refinement techniques present in finite element method(FEM)simulations implemented in the ANSYS program.The investigated floor dynamic response was calculated through the consideration of the dynamic loadings imposed by the mechanical equipment,simulated based on the use of harmonic forces applied on the concrete slabs.Furthermore,the dynamic structural response was performed considering several scenarios for the positioning of the equipment,in order to verify the occurrence of excessive vibration.The fatigue assessment is based on a linear cumulative damage rule through the use of the Rainflow-counting algorithm and S-N curves from traditional design codes.The results of this investigation indicated that the equipment position affects directly the floor dynamic structural response and also significantly influences the structure service life.