BOX OUTS PROBABLE CAUSE OF SINGAPORE FLYOVER FAILURE

Reasons for the failure of the structure, one of 11 new bridges on the 25 km Long Pan Island Expressway, are suggested. The possibility of low strength concrete or inadequate prestressing have been ruled out. It is not clear if the original design was adequate to accommodate the large box outs or why they were not partially filled before removal of the falsework. The original plan was to leave out a 1.5 M long, 1 M wide and 450 mm deep box above each of the stressing points in each of the six webs across the deck. However to simplify construction and provide better access for stressing a single full width box was considered more suitable. The removal of this box altered deck strength, and it is not clear if the client or contractor checked the revised design. During the 20 minutes or so of the collapse, both carriageways hinged along one of the lines of the box outs, the long time taken preventing a similar collapse on the other box out. (TRRL)

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 27-28
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00309307
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jun 9 1980 12:00AM