EVALUATION OF THE DESIGN OF SIMPLE-SPAN PRECAST PRESTRESSED BRIDGE GIRDERS MADE CONTINUOUS FOR COMPOSITE DEAD AND LIVE LOADS. FINAL REPORT

A detailed investigation was undertaken to study the time-dependent behavior and relevant design criteria for simple-span precast prestressed bridge girders made continuous. A survey of different DOTs across the country was conducted by circulating questionnaires to determine the current practice of analysis and design of this type of bridge. Creep and shrinkage tests were conducted on steam cured concrete at an early age since this type of concrete is used in most precast girders. Computer simulations were carried out using the programs PBEAM and WALL-HINGE to investigate the effects of time-dependent material behavior and design parameters on the effective continuity for live load plus impact. The results indicate that positive moment connections in the diaphragms at the piers are not required as they have no structural advantages. The results also indicate that the effective continuity for live load plus impact can vary from 0 to 100% depending on the design parameters and sequence of construction. The computer analysis was used to determine an upper limit for the amount of negative moment reinforcement over the supports to ensure full moment redistribution and strength. Computer programs were developed based on simplified analysis to determine the time-dependent restraint moments and service moments upon application of live load. Recommendations for design procedures are included with examples. Suggestions for further research are also included.

• Corporate Authors:

  Arizona State University, Tempe

  Department of Civil Engineering
  Tempe, AZ  United States  85287

  Arizona Department of Transportation

  206 South 17th Avenue
  Phoenix, AZ  United States  85007

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Fafitis, A
  • Divakar, M
• Publication Date: 1988-10

Media Info

• Pagination: 56 p.

Subject/Index Terms

• TRT Terms: Computer programs; Creep tests; Data collection; Deformation; Design; Girders; Live loads; Measurement; Moments (Mechanics); Precast concrete; Prestressed concrete; Questionnaires; Recommendations; Shrinkage; Simulation; State departments of transportation; Static loads; Surveys; Time dependence
• Uncontrolled Terms: Continuity
• Old TRIS Terms: Moments; Shrinkage tests
• Subject Areas: Bridges and other structures; Design; Highways; Research; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00619197
• Record Type: Publication
• Report/Paper Numbers: FHWA-AZ88-259
• Contract Numbers: PL-1(31) Item 259
• Files: TRIS, USDOT, STATEDOT
• Created Date: Feb 29 1992 12:00AM