CRACK EVALUATION AND REPAIR OF CANTILEVER BRACKET TIE PLATES OF EDISON BRIDGE

The Edison Bridge on Route 9 over the Raritan River in New Jersey is a riveted two-girder floor beam structure that was built in 1944. Cracks were discovered in several tie plates connecting the cantilever brackets to the main girder and floor beam in the continuous span, the 25.8-m (84-ft, 6-in.) spans, and the 40.4-m (132 ft, 6-in.) spans. Several cracked tie plates were removed so that the cause of cracking could be evaluated. The investigation included metallographic and fractographic examinations of crack surface areas that were not damaged extensively by corrosion. Striation spacing measurements showed that the cyclic stress driving the crack was independent of crack length, characteristic of displacement-induced fatigue. Field testing to determine the live load stress levels confirmed that in-plane bending of tie plates was the principal cause of the fatigue cracking and that the cantilever bending stresses were negligible. The measurements also suggested that a loss of frictional composite action occurred as the slab deteriorated. This led to high cyclic stresses in tie plates, with the maximum stress range varying between 69 and 138 MPa (10 and 20 ksi). Fatigue cracking initiated at flame-cut plate edges subjected to the maximum in-plane bending stress from distortion. Cracking was also aggravated by corrosion loss of section. Future inspection procedures were developed to enhance crack detection, which is highly variable because of the uncertainty of composite action. Retrofit recommendations for failed tie plate replacement were developed as well as means to eliminate the problem when the structure is rehabilitated.

Language

  • English

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 15-25
  • Monograph Title: FOURTH INTERNATIONAL BRIDGE ENGINEERING CONFERENCE, SAN FRANCISCO, CALIFORNIA, AUGUST 28-30, 1995. CONFERENCE PROCEEDINGS, 2 VOLUMES
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00711707
  • Record Type: Publication
  • ISBN: 0309061091
  • Files: TRIS, TRB
  • Created Date: Sep 6 1995 12:00AM