ENVIRONMENTAL STRESSES IN FLEXIBLY SUPPORTED BRIDGES

At present, no rational design method is available to account for movements and stresses in composite-girder bridges supported by flexible stub abutments. Because flexible stub abutments are frequently used, the objectives of this study were to: 1) develop a method for calculating environmentally induced movements and stresses and 2) compare the magnitude of these stresses induced in three types of construction for a 11-26-26-11-m (35-86-86-35 -ft) four span six stringer composite-girder highway bridge located in mid-Missouri. Three types of support connections were investigated; 1) frictionless bearings, 2) non-integral end bents, and 3) integral end bents. Twenty years of recorded weather data were used for selection of upper and lower bound environmental loadings. Using these loadings as boundary conditions to the general heat flow equation, a finite element method was used to calculate resultant temperature distributions within a typical interior girder. These temperature distributions were then used as input to a slab-beam type element for calculation of the thermally induced stresses within the girder. Restraints imposed by the substructure, i.e. the bridge piers and earth embankments were modeled by linear springs. The results show that thermally induced stresses are significant for all three types of construction. Maximum beam stresse for the three supports were approximately 35%, 35%, and 52% of the allowable for frictionless bearings, non-integral abutments, integral abutments, respectively. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 262-270
  • Monograph Title: Bridge Engineering. Volume 1
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183773
  • Record Type: Publication
  • ISBN: 0309026962
  • Files: TRIS, TRB
  • Created Date: Dec 12 1978 12:00AM