Development of a novel full-scaled self-centering brace with notched steel tubes

Abstract

A novel self-centering brace with notched steel tubes (SCB-NST) was developed and experimentally studied. The proposed SCB-NST consists of a novel notched steel tube (NST) for energy dissipation and disc springs for self-centering, respectively. Three full-scaled specimens were tested to investigate the hysteresis behavior under cyclic loading. These specimens include a brace with NST only, a brace with disc spring only, and an SCB-NST. The first two tests were specifically conducted to obtain the contributions of the NST and disc springs alone, respectively. The test results illustrate that the first proposed NST displays excellent energy dissipation and deformation capabilities. The proposed SCB-NST exhibits a stable flag-shaped hysteresis behavior, distinguished self-centering, and significant energy dissipation capacity without residual displacement. Furthermore, experimental findings reveal that the disc spring functions as a secondary defense line of the SCB-NST system upon sudden failure of the NST. The cyclic test of the brace with disc spring only shows that the friction between the disc springs should not be neglected, especially when quantities of large-diameter disc springs are stacked. The modular design of the proposed SCB-NST facilitates the replacement of energy-dissipating components, allowing for efficient maintenance and ultimately achieving the design objective of promoting reusability and resource conservation. The SCB-NST, equipped with two NSTs featuring different ultimate displacements, has been confirmed through finite element analysis to have three defense lines, which improves the reliability and redundancy of the SCB-NST system. The parametric finite element analysis results reveal that the thickness of the energy-dissipation ring has the most significant influence on the load-bearing capacity and energy-dissipation capability of the SCB-NST. Concurrently, the pre-pressed force of the disc spring is crucial for eliminating the residual displacement of the SCB-NST.