A NEW POST-TENSIONED SELF-CENTERING BRACE WITH ADJUSTED STIFFNESS AND DEFORMATION CAPACITIES
Journal
World Conference on Earthquake Engineering proceedings
Journal Volume
2024
ISSN
30065933
Date Issued
2024
Author(s)
Huang, Li-Yu
Abstract
Buckling-restrained braces (BRBs) have been verified to provide a stable hysteretic response in steel braced frames, but their residual deformation occurs whenever providing large energy dissipation to frames at large lateral drifts. Self-centering braces (SCBs) have been developed to reduce the residual deformation of frames based on a flag-shaped hysteretic response, but have a much higher initial axial stiffness before the activation, which may result in a higher design base shear when compared to a frame with BRBs. Therefore, this work was aimed to develop a new self-centering brace with adjusted axial elastic and post-yield stiffnesses and deformation capacity such that the brace response could be designed based on specified yield and ultimate drifts of a frame. Combining disc springs and one of the compression members together in the original SCB could achieve a new response characteristic, providing an alternative to tune the SCB structural property. This work first introduces the mechanics and deformation mechanism of the proposed SCB and performs a parametric study to investigate the effect of disc spring stacks on the hysteretic response of SCBs. A test program is then conducted to identify key design parameters of the spring stack and new brace, which includes cyclic tests of disc spring stacks in different serial and parallel combinations and full-scale steel SCBs. Each 3800 mm-long SCB is composed of post-tensioning high-strength steel tendons, compression steel members, disc spring stacks, and bolted friction device for energy dissipation. The hysteretic responses of the new SCB with different design parameters are used to validate the mechanics, simulation, and ability for the axial stiffness and deformation adjustment based on combinations of disc spring stacks.
Subjects
cyclic test
disc spring stacks
Post-tensioned self-centering brace
stiffness adjustable
tendons
Publisher
International Association for Earthquake Engineering
Type
conference paper