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Type of Document Dissertation Author Shen, Qiang URN etd-01152007-094549 Title Seismic Analysis, Behavior, And Design of Unbonded Post-Tensioned Hybrid Coupled Wall Structures Degree Doctor of Philosophy Department Civil Engineering and Geological Sciences Advisory Committee
Advisor Name Title Kent Harries Committee Chair David Kirkner Committee Member Tracy Kijewski-Correa Committee Member Yahya Kurama Committee Member Keywords
- unbonded
- coupled wall
- post-tensioned
- top and seat angles
Date of Defense 2006-12-07 Availability unrestricted Abstract This dissertation focuses on the development of a new type of hybrid coupled wallstructure for seismic regions. Coupling of concrete wall piers is achieved by posttensioning
steel beams to the walls using unbonded post-tensioning tendons. Different
from conventional hybrid coupled walls, the coupling beams of the new system are not
embedded into the walls. Steel top and seat angles are used at the beam-to-wall
connections for energy dissipation.
Unbonded post-tensioned hybrid coupling systems offer important advantages over
conventional coupling systems, such as simplified construction, ability to undergo large
lateral displacements with little damage, and self-centering capability. Analytical
investigations are conducted on the nonlinear behavior of floor-level coupled wall
subassemblages and multi-story structures under combined lateral and gravity loads. Both
finite element and fiber element analytical models are developed. The effects of design
parameters (e.g., amount of post-tensioning, beam/wall properties) on the behavior of the
structures (e.g., strength, energy dissipation, deformation capacity) are investigated.
Systems with precast concrete walls as well as monolithic cast-in-place concrete walls are
considered. The behavior of the proposed coupled wall system is compared with the
behaviors of uncoupled walls and conventional systems with embedded steel coupling
beams. The analytical results are used to develop approximate procedures to estimate the
nonlinear load-deformation behavior of the structures without sophisticated analytical
models.
The results from eleven half-scale experiments of floor-level unbonded posttensioned
hybrid coupled wall subassemblages are also summarized in this dissertation.
The tests results are used to validate and improve the analytical models, evaluate critical
structural components that can limit lateral strength and ductility, and make
recommendations for practical applications.
Finally, a performance-based seismic design approach is developed for unbonded
post-tensioned hybrid coupled wall structures. Two prototype eight-story hybrid coupled
wall systems are designed using the proposed procedures. Evaluations of the global and
local behavior of the structures are conducted based on nonlinear static lateral load
analyses as well as dynamic time-history analyses under selected ground motion records.
The results from these analyses are ultimately used to critically evaluate the validity of
the design approach and procedures in achieving the target design performance objectives
for the structures.
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