Doctoral Dissertations

Orcid ID

https://orcid.org/0000-0002-0792-0585

Date of Award

8-2025

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Civil Engineering

Major Professor

Nicholas E. Wierschem

Committee Members

Mark Denavit, Timothy Truster, Fernando Moreu

Abstract

This dissertation investigates the dynamic behavior and performance enhancement of structural systems equipped with strongback mechanisms under seismic loading. Strongback systems are designed to mitigate soft-story collapse by promoting a uniform story drift profile. While these systems offer promising improvements to seismic resilience, important questions remain regarding their robustness and effectiveness under varying structural and seismic conditions. To address these gaps, a comprehensive investigation is conducted using both experimental and numerical approaches. This study first examines whether strongbacks can maintain their effectiveness in the presence of vertical stiffness irregularities and evaluates the impact of damper arrangement—distributed versus concentrated—on structural performance. This dissertation then explores the behavior of segmental strongbacks, in which the spine is divided by a mid-height joint to reduce internal force demands and floor accelerations in taller buildings, with particular focus on the role of joint stiffness. Finally, the research investigates the integration of inerters—devices that generate force proportional to relative acceleration—both as standalone systems and in combination with strongbacks, to assess their potential in enhancing seismic performance or serving as alternative control strategies. Through a combination of shake table testing and numerical simulations, this dissertation aims to clarify the mechanics, effectiveness, and design implications of various strongback configurations. By characterizing the interaction between system components, modal deformation patterns, and seismic input, the study helps to develop additional understanding and improvement of strongback-based systems. Ultimately, the findings contribute to advancing earthquake-resistant design by equipping structural engineers with deeper insight and greater flexibility in applying strongback solutions to mitigate seismic risks in buildings.

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