Details:

Creators:
Kunnath, Sashi K. ; Abrahamson, Norman ; Chai, Y.H. ; Erduran, Emrah ; Yilmaz, Zeynep
Kunnath, Sashi K. ; Abrahamson, Norman ; Chai, Y.H. ; Erduran, Emrah ; Yilmaz, Zeynep Less -
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.


Format:
PDF
Funding:
59A0434
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:1cc3d499534c14e0919e3f3676701fc0ce1df10232f7bc95da8edc787f6ae48b
Download URL:
https://rosap.ntl.bts.gov/view/dot/27537/dot_27537_DS1.pdf
File Type:

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