ABSTRACT
The dynamic analysis of a cable-stayed footbridge built recently in Poland was presented in the paper. The footbridge serves to carry pedestrians over the national road. The total length of the object is 50.2 m. The structural system consists of two post-tensioned pre-stressed concrete girders and a pre-stressed pylon. Firstly, the dynamic characteristics of the footbridge were evaluated. The analysis revealed that the lowest natural frequency 2.5 Hz coincides with the frequency of pedestrian steps (walking or running) which may result in the resonance phenomenon. Then, vibrational comfort criteria were assessed. It occurred that the criterion of maximal vertical accelerations was exceeded for a group of six people running perfectly synchronized. The footbridge serves for standard use and it rarely may be crossed by large groups of people. Hence, the level of vibrational comfort of the footbridge was assessed as very high.
