Serviceability assessment of a pedestrian bridge: Concrete vs. GFRP composite deck

摘要

In the paper the dynamic analysis and the assessment of the dynamic behaviour of a cable-stayed footbridge was carried out. Two variants of the footbridge deck were analyzed: the concrete deck and the deck made of glass-fibre-reinforced polymers (GFRP). Firstly, the natural frequencies and modes of vibration for both variants were calculated. Then, vibrational comfort criteria under pedestrian loading for both variants of the deck were assessed. It occurred that in the case of the concrete deck the first natural frequency was located in the range of the typical vertical vibrations caused by a single runner. The resonance risk was assessed as 'medium'. Hence, the dynamic response of bridge to a pedestrian running was calculated. This analysis revealed that the vertical comfort criteria were not exceeded. In the case of the GFRP deck, the first frequency was outside the range typical for vibrations caused by pedestrians. The risk of resonance for the structure with GFRP deck was ruled out. Thus, further dynamic analysis of the footbridge was unnecessary.