Britain's first automatic live deflection monitoring system was crucial to the strengthening of the Wye cable stayed bridge which forms part of the Severn crossing. Changes in the profile of the bridge deck were monitored during work to erect tower extensions and replace the four old steel cables of close packed strands with eight new cables arranged in open array. Measurements were taken at nine points inside the box structure near the new anchorages checking levels against a fixed concrete foundation datum. Readings from the tilting stations on the towers and ambient temperatures are also needed. The sensors operate by sensing variations in fluid pressure within a system of tubes. By accurately determining the fluid density and average pressure changes, the average change in the fluid head and hence the relative level of the station can be found with respect to the datum. Level data obtained from the entire bridge is relayed by a digital communications network back to the computer in the Service building. Precise knowledge of the actual behaviour of the structure under complex loading can be used to determine future maintenance strategies. (TRRL)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
  • Publication Date: 1990-8-30


  • English

Media Info

  • Pagination: p. 24-25
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00617433
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 30 1991 12:00AM