Award Date

8-1-2016

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Civil and Environmental Engineering and Construction

First Committee Member

Ying Tian

Second Committee Member

Nader Ghafoori

Third Committee Member

Samaan G. Ladkany

Fourth Committee Member

Aly Said

Fifth Committee Member

Zhiyong Wang

Number of Pages

224

Abstract

Given the aging infrastructure in the United States, a study was conducted on an older bridge in Nevada to determine its performance under the maximum considered earthquake. A suite of eight synthetic site-specific ground motions, including a spectrum-matched “RSP” record, were applied along both the longitudinal and transverse axes of Bridge G-953 in Las Vegas, Nevada. The supplementary materials contain the original drawings of Bridge G-953 for reference, including changes to the expansion joints and the addition of cable restrainers at the in-span hinges. A detailed model, including the effects of column nonlinearity, material degradation such as shear keys, abutment soil stiffness, and restrainers at the in-span hinges of the superstructure (which were not part of the original design), was developed to capture both local demands and the global response of the structure. Comparison of the average demand from the seven regular ground motions (“Avg 1-7”) with “RSP” was made to determine if the “RSP” record can be a computationally efficient estimation of seismic demand to a structure. Analysis results indicate that while the “RSP” record adequately predicted some force demands, it failed to capture extensive nonlinear deformation such as plastic hinge rotation demand. Displacement-controlled shear failure caused by excessive plastic hinge rotations and flexural distress in the concrete and longitudinal steel were found to be the governing limit states for the average response, creating a possibility of collapse. Localized failures, including rupture of the restrainers, cracking of the shear keys, and large permanent abutment displacements, are also possible. The primary vulnerability of the bridge is in the substructure, where the spacing of transverse reinforcement is too large and the pinned bases of some piers allow large lateral drifts.

Keywords

Bridge G-953; Failure; Finite Element Model; Las Vegas; Nevada Department of Transportation (NDOT); OpenSEES

Disciplines

Civil Engineering

Language

English

Comments

Supplemental file: PDF, 34 pages.

The supplementary materials contain the original drawings of Bridge G-953 for reference, including changes to the expansion joints and the addition of cable restrainers at the in-span hinges.


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