Design, Analysis, and Seismic Performance of a Hypothetical Seismically Isolated Bridge on Legacy Highway

The need to maintain the functionality of critical transportation lifelines after a large seismic event motivates the strategy to design certain bridges for performance standards beyond the minimum required by bridge design codes. To design a bridge to remain operational, one may stiffen and strengthen the load carrying members to increase the capacity, or alternatively use response modification devices such as seismic isolators to shift the dynamic characteristics of the bridge, henceforth reducing the seismic demands. Seismic isolation systems are attractive because they are directly conducive to accelerated bridge construction techniques. The two strategies are compared for a typical Utah highway bridge, using a three-span, pre-stressed concrete girder bridge that crosses Legacy Highway as a case study example. The existing Legacy Bridge, which was designed as a Standard bridge for a 2500-year return period earthquake, is evaluated as an Essential bridge for a 1000-year return period earthquake. Subsequently, this bridge is redesigned and evaluated as a seismically isolated bridge. Configuration changes needed to accommodate a seismic isolation system are discussed, and reductions to column and foundation elements are proposed. Example seismic isolator designs are provided for several different types of isolation systems commonly used in the United States. Inspection and maintenance practices for seismically isolated bridges are discussed.

• Record URL:
  https://drive.google.com/file/d/1f2Itjq6breWDPLM2UAVBeyyEMNIU-T71/view?usp=sharing
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/23890
• Corporate Authors:

  Utah State University, Logan

  Department of Civil and Environmental Engineering
  2333 Engineering, 4110 Old Main Hill
  Logan, UT  United States  84322

  Utah Department of Transportation

  4501 South 2700 West
  Salt Lake City, UT  United States  84114-8410

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ryan, Keri L
  • Richins, Brian
• Publication Date: 2011-1

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Figures; Tables;
• Pagination: 179p

Subject/Index Terms

• TRT Terms: Base isolation; Bridge design; Earthquake resistant design; Performance measurement; Prestressed concrete bridges
• Geographic Terms: Utah
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01365285
• Record Type: Publication
• Report/Paper Numbers: UT-11-01
• Contract Numbers: 08-9182
• Files: NTL, TRIS, USDOT, STATEDOT
• Created Date: Mar 20 2012 12:16PM