Vibration analysis and human comfort investigation of floors when subjected to rhythmic human activities

Resumo

Nowadays, determined buildings structural problems can be associated, for example, to floors
excessive vibrations subjected to human rhythmic activities. This type of structural project situation can occur
when the rhythmic activities are performed in a group, due to the fact that produces a high degree of
synchronization, especially when there is the proximity between one of the excitation frequencies and the floor
natural frequencies. This way, this research work consists of the assessment of the structural dynamic response
of a real reinforced concrete floor with dimensions of 16 m by 35 m and a total area of 560 m2 located on the
eighth story of the State University of Rio de Janeiro (UERJ). The main focus of the investigation is to study the
human-structure interaction dynamic effect between the occupants and the reinforced concrete floor through the
use of several dynamic load traditional only-force models and also based on the use of biodynamic systems
(mass-spring-damper systems). The numerical modelling of the reinforced concrete floor was performed using
the ANSYS program, based on usual modelling techniques adopting the mesh refinement present in the Finite
Element Method (FEM). The maximum values related to the floor dynamic structural response were investigated
and compared with the human comfort criteria limits. Therefore, it was verified that the floor presents excessive
vibration and human discomfort when the only force models were considered in order to generate the dynamic
loads. On the other hand, when the dynamic response of the structure was evaluated considering the dynamic
load models generated based on the use of biodynamic systems the structural system attends the human comfort
criteria and there are no excessive vibrations. However, it must be emphasized that this dynamic loading
mathematical model (biodynamic systems) was formulated based on experimental tests where the dynamic
characteristics of the people and the human damping were included in the formulation.