Development of guidelines for incorporation of vertical ground motion effects in seismic design of highway bridges.

Details

• Creators:
  Kunnath, Sashi K. ; Abrahamson, Norman ; Chai, Y.H. ; Erduran, Emrah ; Yilmaz, Zeynep
• Corporate Creators:
  University of California, Davis. Department of Civil and Environmental Engineering
• Subject/TRT Terms:
  • Bridges
  • Design and construction
  • Earthquake effects
• Publication/ Report Number:
  CA/UCD-SESM-08-01
• Resource Type:
  Tech Report
• Geographical Coverage:
  California
• Corporate Publisher:
  California. Dept. of Transportation. Division of Research and Innovation
• Abstract:
  This study was undertaken with the objective of assessing the current provisions in SDC-2006 for incorporating ; vertical effects of ground motions in seismic evaluation and design of ordinary highway bridges. A ; comprehensive series of simulations was carried out on a range of typical bridge configurations to isolate the ; effects of vertical motions. Results of these analyses reveal that vertical ground motions can have a significant ; effect on (i) the axial force demand in columns; (ii) moment demands at the face of the bent cap, and (iii) ; moment demands at the middle of the span. The first two issues are found to be less of a concern in the present ; study since the axial capacity of the columns and the moment capacity of the girders at the face of the bent cap ; are generally adequate to resist the increase in the respective demands due to vertical effects. On the other ; hand, the amplification of negative moments in the mid-span section is identified as the primary issue that should ; be addressed in the context of existing seismic guidelines in SDC-2006. In particular, the current requirement ; that vertical ground motions be considered only for sites where the expected peak rock acceleration is at least ; 0.6g is not an adequate basis to assess the significance of vertical effects. A second SDC criterion that is in ; need of reexamination is the design specification for the consideration of vertical effects by means of a static ; load equivalent to 25% of the dead load applied in the upward and downward directions. The reinforcement ; resulting from this requirement is found to be inadequate for a significant number of cases examined in this ; study. It is also shown that an elastic response spectrum analysis is an effective tool to determine the effects of ; vertical ground motions on the bridge superstructures. A set of vertical design spectra and a simplified design ; procedure that uses the proposed elastic spectra were developed.
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• Format:
  PDF
• Funding:
  59A0434
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/27537/dot_27537_DS1.pdf
• File Type:
  [PDF - 2.72 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:1cc3d499534c14e0919e3f3676701fc0ce1df10232f7bc95da8edc787f6ae48b