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Event Details

PhD Dissertation Defense

Evaluation of Ground Motion Duration Effects on the Damage Prediction of Building and Bridge Structural and Soil-structural Systems

Thursday, September 14, 2017 1:00 PM - 3:00 PM

Candidate: Andre Belejo

Advisor: Dr. Andre Barbosa 

The role of ground motion duration on the seismic performance of civil engineering structures remains unclear. Thus, the role of earthquake strong ground motion duration is assessed in a three manuscript thesis, which includes: (1) assessment of the effects of ground motion duration on the seismic performance of a model of a three-dimensional (3-D) plan-asymmetric reinforced concrete building tested in Europe; (2) determination of the influence of ground motion duration and the impact of the retrofit solution of columns using titanium alloy bars employed on vintage bridges built in the 1950s – 1970s in the western United States; and (3) estimation of the effect of soil-structure interaction (SSI) on the assessment of ground motion duration of two steel moment resisting frame buildings. 

In this thesis, nonlinear finite element models of the building and bridge structures are developed in OpenSees and validated using experimental data when these were available. Then, the models are subjected to long- and short-duration earthquake ground motions sets, in which each short- and long-duration ground motion pair have similar spectral shapes. In the process, a new ground motion selection procedure is proposed to isolate the effect of duration on the structural response of 3-D structures subjected by bi-directional ground motions. 

Damage index-based fragility curves are proposed in this work. These are based on damage assessment of the structures analyzing global and local responses estimated using two damage indices available in the literature.

A new phenomenological soil-structure interaction model is implemented in OpenSees for analyses performed in the third part of this thesis. Soil variability is explicitly considered and imposed on the numerical models to capture the random field variability of the soil properties at site. The impact of the soil variability at the site is assessed at the serviceability and ultimate limit states, and seismic fragility curves are developed for the case that accounts for this source of soil parameter uncertainty.

Results in manuscript 1 indicate that for the vintage plan-asymmetric building analyzed, the ground motion duration plays an important role in the damage estimation. For the bridge models, in manuscript 2, the proposed retrofit solution applied to the bridges columns provides a significant increase to the structural strength and deformation capacity; however, the retrofit solution is not as efficient when the bridge has columns with different lengths along its longitudinal direction versus the ideal case when the bridge has columns with the same lengths. The ground motion duration plays a role in the damage predicted by the two damage indices in both non-retrofitted and retrofitted bridges.

Lastly, in manuscript 3, the inclusion of SSI effects increases the steel moment resisting frame building measured response of peak and residual deformations, and the ground motion duration plays an important role in the damage predicted when considering SSI effects. 


Kearney Hall (campus map)
Sch of Civil/Constr Engr
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