MODEL STUDIES FOR VOIDED POSTTENSIONED CONCRETE SLAB BRIDGES

A discussion of design, construction, instrumentation and loading of scale models of a three-span, straight slab bridge and a two-span, skew slab bridge is presented in this report. The models contained longitudinal circular voids having similar proportions to prototype bridges. Longitudinal prestress was included and provision was made for various arrangements of transverse prestress. Both the models and the instrumentation responded elastically to loads. The results could be verified by simple theories. The significant conclusions derived from the test series are: 1) Large transverse tensile stresses are present in many areas of the top surface of the model slab bridges as a result of longitudinal prestress. 2) In-plane transverse tensile stresses result from the longitudinal prestressing load. 3) Transverse prestress can effectively introduce compressive stresses into zones where the longitudinal prestress might cause cracking. The intensity and the arrangement of the transverse prestress requires considerable study for a given structure. 4) Transverse prestress located perpendicular to the longitudinal voids appears to be efficient in the span sections of the straight and skew models. 5) The model structures behaved as orthotropic slabs and not beams. Transverse moments and stresses in the end support region and in the area of the intermediate supports result from this basic behaviour as a slab. These effects are significant in design and are not fully taken into account by current design procedures based on one-dimensional beam type analysis. /RTAC/

  • Corporate Authors:

    Ontario Ministry of Transportation & Communic, Can

    1201 Wilson Avenue
    Downsview, Ontario M3M 1J8,   Canada 
  • Authors:
    • Meades, P
    • Green, R
  • Publication Date: 1974-8

Media Info

  • Features: Figures; References;
  • Pagination: 62 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00129471
  • Record Type: Publication
  • Source Agency: Transportation Association of Canada
  • Report/Paper Numbers: RR 195 R&D Rept.
  • Files: TRIS
  • Created Date: Mar 10 1976 12:00AM