Some recently constructed footbridges have been criticised by the public for their susceptibility to vibration. A limit to the allowable acceleration of a footbridge deck, vibrating under pedestrian loading, is proposed, based on experimental studies of human tolerance. A formula is derived for calculating the maximum vertical acceleration of a footbridge due to the applied dynamic loading of a walking man. In specifying the magnitude of the dynamic load to be used in design rules it was decided that the more sensitive existing footbridges should be considered just acceptable. This led to a dynamic load equivalent to one pedestrian. Abnormal loading by a group of vandals deliberately exciting a footbridge at its natural frequency was considered. Lack of information on possible energy imput, the likely accelerations and the effective number of vandals made it impossible to propose design rules. However, calculations indicated that this loading would normally be covered by static loading criteria. Highway bridges were also considered but it was concluded that the dynamic effects of individual or small groups of vehicles would be well within the existing allowance for static live load. Wind induced vibration is not considered in this paper. /Author/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 90-106

Subject/Index Terms

Filing Info

  • Accession Number: 00172172
  • Record Type: Publication
  • Report/Paper Numbers: TRRL Rpt. 275 Proceeding
  • Files: TRIS
  • Created Date: Apr 12 1978 12:00AM