EXPERIMENTAL AND ANALYTICAL STUDY OF A TWO-SPAN POST-TENSIONED BRIDGE SLAB. INTERIM REPORT

This is the second in a series of reports documenting a research program aimed at detailed investigation of a new type of post-tensioned bridge structure that has a moderately thick concrete slab resting directly on columns without bent caps. In this program two scaled laboratory models, named Model 1 and Model 2, are tested along with instrumentation of a full-scale, three-span skewed bridge. This report deals with the second laboratory model. A large, two-span 3/10ths scale model bridge is constructed and tested in the service, overload, and ultimate load ranges. Dimensions of the slab are 55.5 ft x 17.5 ft x 9 in. (16.9 m x 5.33 m x 0.229 m). In addition to uniformly distributed longitudinal post-tensioning, a band of tendons is placed in a narrow region directly above the supporting columns. Arrays of 185 strain gages, 18 LVDTs, 10 load cells, and 27 survey points serve to gather data for dead, live, and time-dependent loadings. Response of the structure is studied in five stages. First, prestressing force and dead load are applied. Both short- and long-term effects of these loads are of interest. Special attention is given to the distribution of internal stresses due to transverse prestressing. Second, AASHTO design lane loads are applied statically to determine effectiveness of the transverse prestressing. Third, an AASHTO HS20-44 truck load is applied dynamically by means of a series of load actuators. Serviceability of the slab is checked for 200,000 cycles of the simulated truck. Fourth, a series of overloads are placed on the slab in a variety of critical locations. Lastly ultimate loads are applied in the positive and negative bending moment regions followed by an ultimate shear load placed at the edge of the slab near the anchor heads of the transverse tendons. Complementary nonlinear finite element analyses of the dead, live, and time-dependent loadings provide confidence in the simulation capability of the code.

• Supplemental Notes:
  • Research study title: Evaluation of Factors Affecting Slabs Due to Localized Post-Tension Forces.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas Department of Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Roschke, P N
  • Pruski, Kevin R
  • Smith, C D
• Publication Date: 1992-2

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 144 p.

Subject/Index Terms

• TRT Terms: Breaking loads; Bridge decks; Data collection; Deformation curve; Finite element method; Internal forces; Live loads; Loads; Oversize loads; Posttensioning; Prestressing; Static loads; Stresses; Structural analysis; Structural mechanics; Time duration
• Uncontrolled Terms: Internal stresses; Long term; Model tests; Overloads; Short term; Structural response
• Old TRIS Terms: Shear loads; Time dependent loadings; Transverse prestressing
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00626698
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-92/1182-2, Res Rept 1182-2, TTI: 2-5-88/0-1182
• Contract Numbers: Study 2-5-88/0-1182
• Files: TRIS, USDOT, STATEDOT
• Created Date: Feb 1 1996 12:00AM