UBC Theses and Dissertations
Development of dual replaceable-link eccentrically braced frames using equivalent energy based design procedure Neitsch, Jesse Eric Edward
Conventional seismic force resisting systems (SFRSs) rely on the use of ductile design philosophy, where structural components are designed to undergo large inelastic deformations to dissipate the sudden surge of the earthquake energy. This design philosophy has shown to be very effective in preventing structural collapse. However, the extensive inelastic deformation usually leads to significant damage to the structural and non-structural components. Many earthquake reconnaissance reports show that this design philosophy typically leads to hefty financial losses. Eccentrically Braced Frames (EBFs) have been proven through testing and earthquakes to exhibit a high level of ductile behaviour. However, the damage of the link leads to hefty repair costs, which lead to the Replaceable-Link Eccentrically Braced Frame (REBF). A well-tuned link can control the response of the REBF, which provides the advantage for the REBF over an EBF. While the link is designed to yield, and deform, the rest of the REBF and gravity system are designed to remain elastic. This mechanism makes the link act as a fuse in the REBF system, which allows the structure to be more resilient towards earthquakes. In this study, a novel seismic design methodology named the Equivalent Energy-Based Design Procedure (EEDP) was implemented for the seismic design of two REBFs operating in parallel, which is referred to as the Dual REBF (DREBF) system. The conventional Equivalent Static Force Procedure (ESFP) was also used to achieve an alternate, comparative model. The designs and the design procedures themselves were compared to highlight potential benefits of designing from an energy based perspective. EEDP allows the designers to select different performance objectives at different shaking intensities, where the structure can be designed to achieve these objectives using simple hand calculations. More importantly, the design can be achieved without iteration. This study demonstrated that the design procedure of one simple prototype building utilizing both the ESFP and EEDP philosophies. Their seismic responses have been analyzed using detailed numerical models developed using OpenSees. The results of the nonlinear dynamic analysis showed that the EEDP designed DREBF can achieve the target performance defined by the designer at different shaking intensities.
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