Parametric study of seismically retrofitted bridge RC columns using shape memory alloys

Research output: Contribution to conferencePaper

Abstract

Traditionally, seismic retrofit of reinforced concrete (RC) columns that lack flexural ductility is carried out using passive confinement techniques such as installing steel jacket, wrapping the columns with fiber reinforced polymer (FRP) sheets, or even casting concrete jacket at the plastic hinge zone. Alternatively, RC columns can be retrofitted using active confinement; a technique that relies on permanently prestressing the columns in the transverse direction. However, the application of active confinement has not been successful due to practical limitations such as time, labor, and costs associated with using mechanical prestressing. By utilizing the unique shape memory phenomenon of Shape Memory Alloys (SMAs), active confinement can be easily applied to the plastic hinge region of the RC columns. Pre-deformed SMAs are installed to retrofit the RC columns, and then high enough heat is provided to activate shape memory of prestrained SMA which results in active confinement pressure. This study focuses on conducting a parametric study based on validated numerical models of RC columns retrofitted using shape memory alloys (SMAs). A fiber section based numerical column model is developed to represent the behavior of a RC column retrofitted with SMAs, and the model is validated with scaled RC column test. The parametric study investigates the effects of design parameters such as volumetric ratio of longitudinal reinforcement, diameter of column, slenderness ratio, and level of the axial load together with the magnitude of the active confinement pressure. A statistical tool, multi-factor analysis of variance (ANOVA), is used to design the parametric study. The effects of possible interactions among design parameters on the seismic performances of the retrofitted columns with SMAs are statistically evaluated through the ANOVA. The results of numerical work clearly demonstrate the effectiveness and superiority of the retrofit method using SMAs. The performed parametric study is used to develop a new design recommendation of an optimum active confinement pressure with respect to important RC column's parameters to achieve certain level of seismic performance.

Original languageEnglish (US)
DOIs
StatePublished - Jan 1 2014
Event10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering, NCEE 2014 - Anchorage, United States
Duration: Jul 21 2014Jul 25 2014

Other

Other10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering, NCEE 2014
CountryUnited States
CityAnchorage
Period7/21/147/25/14

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology

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    Shin, M., & Andrawes, B. O. (2014). Parametric study of seismically retrofitted bridge RC columns using shape memory alloys. Paper presented at 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering, NCEE 2014, Anchorage, United States. https://doi.org/10.4231/D3NK36574