Thesis: Seismic Design of Outrigger Systems for Tall Buildings

With growing population in major cities worldwide, high rise construction is becoming the only practical solution in many highly populated regions. Unfortunately many of these regions are also in seismically active areas. To mitigate economic and social losses during significant earthquakes, it is necessary to design high performance tall buildings to be resilient towards future earthquakes. Vancouver, Canada is located in one of the world’s most seismically active region, known as the Pacific Ring of Fire. The lateral force resisting systems are mostly concrete shear walls. These systems are very efficient for low to moderate height construction. However, as the height of the structures increases, the concrete core wall system become less efficient. To improve the performance of these systems, the outrigger system can be implemented. Outriggers are deep, stiff beams or trusses that transfer forces to the exterior columns, which results to lower overturning moment and lateral deflections for the high rise building. With reduced demands, the core wall can be designed to occupy less area, providing more space for building occupancy. The outrigger can also provide supplemental damping and energy dissipation during wind and earthquake loading, which reduces the demands to the rest of the structure. Previous research on outriggers has focused on the optimization of outrigger location and stiffness, the dynamics of the system, inclusion of viscous dampers, connections to the building core, and general design recommendations based on the cumulative knowledge of practicing engineers. These advances notwithstanding, a clear standard for the seismic design of outrigger buildings has not yet been developed, nor has a comprehensive study been conducted to highlight critical issues under earthquake excitation. My research program aims to fill the knowledge gap in these critical areas.


  • T.Y. Yang, J.C. Atkinson, and L. Tobber (2014). Detailed Seismic Performance Assessment of High-value Contents Laboratory Facility. Earthquake Spectra In-Press.
  • T.Y. Yang, J.C. Atkinson, S. Chan,  (2014). Seismic Performance Evaluation of Typical New Tall Buildings Constructed in Vancouver, Canada. Huixian International Forum on Earthquake Engineering for Young Researchers.


  • Alexander Graham Bell Canada Graduate Scholarship
    Natural Sciences and Engineering Research Council of Canada
  • Faculty of Applied Science Graduate Award
    University of British Columbia
  • Undergraduate Student Research Award
    Natural Sciences and Engineering Research Council of Canada
  • McElhanney Scholarship in Civil Engineeering
    McElhanney Consulting Services Ltd.
  • Trek Excellence Scholarship for Continuing Students
    University of British Columbia