Effect of Shallow Foundation Rocking on Dynamic Response of Bridges

Rocking as an acceptable mode of seismic response has been extensively studied and has been shown to potentially limit local displacement demands. Rocking can act as a form of isolation, reducing displacement and force demands on a bridge, thereby allowing for design of smaller footings and members. As part of a collaborative effort to develop guidelines for the design of bridges supported on piers that rock on their foundations a series of shake table tests of a simple ¼ scale inverted pendulum reinforced concrete bridge column was conducted. These tests are among the first to consider three components of excitation. Testing levels included design and maximum credible earthquake scenarios that created an inelastic response in the test specimen. Concurrent centrifuge testing to determine the inelastic response of soil when similar to-scale systems were allowed to rock developed data which could be used with the shake table tests to create and validate analytic models of the complete rocking response. Analysis shows that full-scale systems allowed to rock on their foundations reduce displacement and force demands without creating a global instability. Analytic models show that short period fixed bases systems tend to have amplified displacements when allowed to rock for a variety of soil profiles.

• Supplemental Notes:
  • Only the abstract is provided for this paper.
• Corporate Authors:

  Multidisciplinary Center for Earthquake Engineering Research

  State University of New York, 107 Red Jacket Quadrangle, P.O. Box 610025
  Buffalo, NY  United States  14261-0025
• Authors:
  • Espinoza, Andres
  • Mahin, Stephen
• Conference:
  • Sixth National Seismic Conference on Bridges and Highways
  • Location: Charleston SC, United States
  • Date: 2008-7-28 to 2008-7-30
• Publication Date: 2008

Language

• English

Media Info

• Media Type: Digital/other
• Pagination: 1p
• Monograph Title: Sixth National Seismic Conference on Bridges and Highways: Seismic Technologies for Extreme Loads

Subject/Index Terms

• TRT Terms: Bridge foundations; Bridge members; Bridge piers; Dislocation (Geology); Dynamic loads; Dynamic structural analysis; Footings; Reinforced concrete bridges; Seismicity; Shaking table tests
• Subject Areas: Bridges and other structures; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01355914
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 28 2011 8:40AM