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David Hillis

Scholar: David Hillis

David Hillis

Major: Civil Engineering/Honors Program

Faculty Mentor: Dr. Saiid Saiidi

Research Topic: "Seismic Modeling of Bridge Components with Conventional and Innovative Design"

Abstract:  Shape Memory Alloy's (SMA's) form a group of metals that display two distinguishing characteristics, pseudo-elasticity and shape memory effect. There are many applications of these metals ranging from eyeglass frames that will return to their original shape after being bent to orthodontic wires. However, consider utilizing this material in a bridge column located in an earthquake prone region of the country. The result would be a bridge that could withstand large deformations and could potentially return to near its original position.

The focus of this research was to explore the results of SMA being placed in the plastic hinge region of a reinforced concrete column to reduce the residual displacement due to seismic loading. Shake table tests have already shown that SMA bars reduce permanent column displacements.  Computer modeling is being used to simulate a seismic test on a single column bent with and without SMA in the plastic hinge region to determine if the SMA bars can also reduce the permanent displacement when the earthquake load is impulsive, a feature of earthquakes in the vicinity of faults.

Performance will be evaluated based on the position of the top of the column after various seismic ground motions. The same near-fault ground motion has been used in all simulations, increasing in magnification for eleven consecutive runs. The computer modeling is conducted using the Open System for Earthquake Engineering Simulation (OpenSees). OpenSees was chosen for its advanced modeling of nonlinear systems. The poster will present a summary of the study and the results obtained thus far.

Earned Baccalaureate Degree: Fall, 2007

Earned Masters Degree: spring 2010, Civil and Enviromental Engineering, University of Nevada, Reno 

Doctoral Program Update: Enrolled in the Hydrology Ph.D. program, University of Nevada, Reno

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