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Amiri Gheshlaghi, Amirhossein

University of British Columbia

Reinforced concrete core wall buildings are the prevalent construction method for high-rise buildings in North America. The seismic performance of these buildings largely depends on the hysteretic response of coupling beams. This thesis studies the impact of design details on the hysteretic response of coupling beams in two phases. Phase one focuses on the diagonally-reinforced coupling beams, while phase two investigates the steel and composite coupling beams. A new database, including 51 tested diagonally-reinforced coupling beams, was developed in phase one. This database investigated the effect of design considerations, such as aspect ratio, beam and diagonal ties, axial restraint, and embedded longitudinal reinforcing, on the structural performance parameters, such as maximum shear capacity, initial stiffness, and rotational capacity of the diagonally-reinforced coupling beams. The analysis of this database led to new insights into the performance of diagonally-reinforced coupling beams. One key finding shows that the rotational capacity of low aspect ratio beams depends on the diagonal reinforcing ratio. Consequently, new design recommendations have been developed. The second phase focused on developing improved wall-to-beam connection detailing for steel and composite coupling beams. The current method, requiring the steel beam to be embedded into the wall with a long embedment length, is challenging to construct. Alternatively, welded bars called auxiliary transfer bars could be utilized to reduce embedment length, which is also challenging to construct. This thesis proposes a new connection method that utilizes compression steel bars, supporting the embedded beam in the bearing and making it easier to construct. The mechanics of the innovative detailing have been explained, and design plots have been provided. To investigate the seismic performance of this new detailing, a finite element model was developed using DIANA FEA 10.6 and verified through experimental studies from the literature. Overall, it was found that the structural performance of steel and composite coupling beams, such as shear force capacity, initial stiffness, and rotational capacity, can be improved by implementing this new connection detailing. Both phases of this thesis offer new insights into improving the seismic performance of diagonally-reinforced, steel, and composite coupling beams, resulting in higher-performing high-rise buildings in Canada.

Text

2024-04-30

Attribution-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88106

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nd/4.0/