Measurements of dynamic response of steel box girder bridges, due to traffic and wind, were obtained for the reassessment of bridge loading rules. Traffic induced deflections were measured on the Tinsley viaduct during four one-hour periods of the day when the largest traffic flows occurred. The response to gale force winds was measured on the Cleddau bridge at Milford Haven and the Wye bridge for longer periods. The measruements of vehicle excited vibrations showed that maximum movements of the test span ranged between an upward deflection of 5mm and a downward deflection of 14mm. The maximum value of deflection to span ration of 1:4000 was therefore very low. The viaduct oscillated about the static defelction principally in the range plus or minus 2mm with a maximum of plus or minus 2.51mm, the levels being structureally acceptable and within the limits of human tolerance. Maximum measured with induced oscillations on the Cleddau and Wye bridges were both lower than predicted from wind tunnel tests. For the Cleddau bridge a peak value of plus or minus 28mm was measured compared with plus or minus 150mm in the turbulent wind tests. The calculated values of natural frequencies were proved to be close to those determined by using an auto correlation technique. Similar differences between measured and predicted response were found on the Wye bridge, the measured values being plus or minus 6mm whereas wind tunnel tests predicted plus or minus 51mm. /Author/

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 56-69

Subject/Index Terms

Filing Info

  • Accession Number: 00172170
  • Record Type: Publication
  • Report/Paper Numbers: TRRL Rpt. 275 Proceeding
  • Files: TRIS
  • Created Date: Apr 12 1978 12:00AM