EXPERIMENTAL DETERMINATION OF THE ULTIMATE CAPACITY OF A COMPOSITE PRESTRESSED BRIDGE UNIT. FINAL REPORT

A 55 ft long prestressed, composite steel girder-concrete slab bridge unit was tested to ultimate load. The unit had previously undergone a series of tests including sustained loading, fatigue loading, and static loading to first yield. The 54 ft, simply supported span was subjected to static loads applied at points 20 ft from the supports. Vertical deflections were measured at the supports and midspan, and horizontal slippage at the slab-girder interface was measured at several locations along the span. Strain gage readings at midspan on the slab surface, slab longitudinal bars, and throughout the depth of the girders were recorded. The bridge unit behaved in a ductile manner, deflecting 18.6 in. before failure occurred. Strain gage readings indicated yielding occurred over nearly the full depth of the girders. Failure was by crushing of the slab at the load application points. The unit supported an applied load 13% greater than the ultimate load predicted using actual material properties. The excess capacity is attributed to strain hardening of the bottom flanges of the girders. Slippage at the slab-girder interface was observed to be small. Existing analysis procedures were found to be adequate for predicting the ultimate capacity of the unit. Load at first yield in a previous test was observed to be lower than predicted. It was determined that the reduction in yield load can be explained by the presence of residual tensile rolling stresses in the bottom flanges of the girders.

• Record URL:
  • https://rosap.ntl.bts.gov/view/dot/89300
• Corporate Authors:

  University of Oklahoma, Norman

  Fears Structural Engineering Laboratory, 303 E Chesapeake
  Norman, OK  United States  73019

  Oklahoma Department of Transportation

  200 NE 21st Street
  Oklahoma City, OK  United States  73105

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Prasad, R
  • WALLACE, B
  • Bush Jr, T D
• Publication Date: 1989-12

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 67 p.

Subject/Index Terms

• TRT Terms: Breaking loads; Bridges; Composite structures; Deflection; Failure; Highway capacity; Load tests; Prefabricated structures; Prestressing; Static loads
• Uncontrolled Terms: Bridge capacity; Composite bridges; Slippage
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00603665
• Record Type: Publication
• Report/Paper Numbers: FHWA/OK 89(05)
• Contract Numbers: Agreement No. 2162
• Files: NTL, TRIS, USDOT, STATEDOT
• Created Date: Feb 28 1991 12:00AM