OMITTING THE STATIC COMPONENT FROM DESIGN DYNAMIC MODELS OF PEDESTRIAN LOAD

Serviceability limit state (SLS) due to pedestrian-induced vibrations should be checked for bridges with fundamental natural frequency less than 5 Hz. In those cases the vibration serviceability requirement should be fulfilled. In current codes and designer´s guidelines the vibration serviceability requirement is determined as a pedestrian comfort criteria thought terms of maximum acceptable acceleration of any part of the bridge deck, although the comfort criteria can be defined as maximum acceptable deflection or velocity at the most unfavourable part of the bridge deck. The design models of dynamic pedestrian load for SLS verification are based on the experimental models of dynamic pedestrian load, but a static component (pedestrian weight) is omitted from the design models of pedestrian load in vertical direction. Justification of omitting the static component from design models is studied through comparison of dynamic response of different single span bridge deck structures with frequency of 2 Hz to design and experimental pedestrian load models. From conducted numerical analysis and comparison of structural response to design and experimental load models it is shown that omitting of the static component is entirely proper in cases when comfort criteria is based on terms of maximum acceptable bridge deck velocity or acceleration.