SEISMIC VULNERABILITY OF STRUTTED-COLUMN BRIDGE BENTS. FINAL TECHNICAL REPORT

Strutted-column bents represent a type of reinforced concrete bridge substructure found in some bridges built before the early 1970s. The bents were designed using steel detailing and confinement that is inappropriate for ductile behavior. These bents consist of two or more columns that are connected by horizontal beams/struts, at some location along the clear heights of the columns. The presence of the struts in these bents causes an increase in the number of locations that inelastic demands can occur relative to the number found in typical bents. The struts also increase both the lateral stiffness and strength of the bents. These features coupled with the poor detailing and confinement cause uncertainty about the seismic performance of the strutted-column bents. The seismic vulnerability of strutted-column bents was assessed by: 1) determining the characteristics and the construction details of the bents in an inventory of bridges with strutted-column bents; 2) evaluating the bents to determine the anticipated inelastic demands that they might experience and their potential to meet these demands; and 3) experimentally testing two subassemblages that were representative of the beam-column joint regions of those bents that were determined to be the most seismically vulnerable. The subassemblages exhibited poor hysteretic behavior after they attained their respective yield displacements because of the deterioration of strut bar anchorage in their B-C joints. The information that was obtained from the three phases of work was used to appraise the seismic performance potential of the bents and the bridges. The bents and the bridges should perform satisfactorily if the displacement ductility demands in the B-C joint regions of the bents are less than four. Large values of the displacement ductility could jeopardize the performance of the bents, and hence the performance of the bridges as well.

• Record URL:
  http://www.wsdot.wa.gov/research/reports/fullreports/361.1.pdf
• 
• Corporate Authors:

  Washington State University, Pullman

  Washington State Transportation Center
  Pullman, WA  United States  99164

  Washington State Department of Transportation

  Transportation Building, 310 Maple Park Avenue SE, P.O. Box 47300
  Olympia, WA  United States  98504-7300

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Pappas, G J
  • Marsh, M L
• Publication Date: 1995-12

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 335 p.

Subject/Index Terms

• TRT Terms: Beams; Bents; Bridge substructures; Columns; Dislocation (Geology); Ductility; Hysteresis; Inelastic stress; Joints; Seismicity; Struts
• Uncontrolled Terms: Beam-column joints; Inelastic response; Seismic response; Vulnerability
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00720101
• Record Type: Publication
• Report/Paper Numbers: WA-RD 361.1, Res Proj T9234, Task 16
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 9 1996 12:00AM