End Zone Cracks for Skewed Pre-Tensioned Box Beam Concrete Girders

Adjacent box beams are widely used in bridge construction because they offer advantages of economy, ease of construction, durability, and appearance. Recently, a skewed deeper box beam section with a large number of strands has been developed. The geometry and amount of pre-stressed tension appear to lead to cracking at the end of box beam in a consistent pattern. The cracking may affect the durability of the bridge, particularly if corrosive materials can seep into the members and affect the pre-stressed strands and transverse tie rods. Some cracked beams were removed from a structure to a manufacturer’s storage yard where these cracks were examined in detail. This study investigates possible causes of these cracks, such as load effects created by pre-stressed tension. A 3-D finite element analysis (FEA) was performed which incorporated nonlinear concrete material properties. The FEA modeled a box beam from Dry Creek Road Bridge with dimensions 1.22 m (48 in.) width, 0.84 m (33 in.) depth, and 28° skew angle, which had experiences cracks at the end. The tensile strains were modeled and the computed locations of the cracks matched well with those observed in the field. The results obtained from FE analysis were also compared with closed-form solutions. The analytical results showed the skewed geometry is the main cause of the cracking. The strain resulting from the transfer of pre-stressed force in concrete along the transfer length had a favorable effect on concrete crack.

Language

  • English

Media Info

  • Media Type: Web
  • Features: References;
  • Monograph Title: Congress on Technical Advancement 2017: Construction and Forensic Engineering

Subject/Index Terms

Filing Info

  • Accession Number: 01692464
  • Record Type: Publication
  • ISBN: 9780784481035
  • Files: TRIS, ASCE
  • Created Date: Oct 4 2018 4:36PM