Human comfort acceptance criteria of pedestrian bridges

Abstract

The assessment of vertical vibrations due to human induced force becomes an inevitable procedure in the design process of footbridges. In past decades the deflection due to live load is limited by span to length ratio and the depth to span length ratio, however such approach had not lead to bridges with acceptable level of vibrations. Nowadays many codes of practices describe the human discomfort in terms of the perceived acceleration of the footbridge or by avoiding specific limit of natural frequency. Many standards apply the concept of baseline curves and its multipliers for specifying floor vibration criteria. The human perception of vibrations is subjective and depends on individual characteristics, psychological influences, and the attitude of people towards the vibration cause. Several standards require a calculation of the dynamic response of a footbridge due to a footfall force; others provide simplified procedures to predict accelerations. The purpose of this study is to investigate the variety of vibration limits and acceptance criteria as stated in international standards and design guides. A comparison study between different methods prescribed in international codes is presented for different pedestrian bridges configurations.