ASSESSMENT OF HUMAN COMFORT IN A FOOTBRIDGE SUBJECT TO DYNAMIC LOADS

Resumo

Footbridges are structures susceptible to excessive vibrations. To avoid this type of problem, it is
necessary to study these, especially the modal characteristics. Thus, the present study aims to perform a numerical
dynamic analysis in finite elements and experimental of a pedestrian footbridge, located in the city of Natal. For
this, a computational model of the structure was developed using the ANSYS 2019 – R3 software, from which a
modal analysis was performed to numerically determine the natural modes and frequencies of footbridge vibration.
Finally, an experimental modal analysis was performed, using the smartphone application iDynamics, in order to
compare the results of the two analyses. The horizontal and vertical numerical frequencies are similar to the
experimental ones and are in the range of 2 Hz for the frequency that characterizes the first lateral vibration mode
and 4 Hz for that corresponding to the first vertical mode. The results achieved are analyzed in light of current
national and international standards and indicate that the structure is in the critical range, which may lead to
resonance problems. They also indicate that a smartphone can be used to perform early and fast measurements of
the natural frequencies of mixed footbridges.