In recent years, the need for more resilient buildings that can recover quickly after seismic events has gained considerable attention in earthquake engineering. A significant development in this area is the use of replaceable steel links in composite frame structures, which can dramatically improve a building's seismic performance while ensuring a faster recovery after an earthquake. The concept behind these systems is to concentrate the plastic deformation and damage in the steel links, serving as structural fuses, while other parts of the structure, such as beams, columns, and joints, remain mostly intact. This allows for the damaged steel links to be easily replaced, restoring the building’s functionality with minimal downtime.
The study presented in Scientific Reports by Liquan Xiong, Zhengchao Guo, Jun Cai, Kaiyu Jiang, and Linyan Li investigates the seismic performance of these replaceable steel links, with a focus on their short length ratios. The researchers conducted a series of low-cycle reversed loading tests on four test specimens with varying length ratios to evaluate their failure characteristics, hysteretic response, and shear strength. The results of these tests provide valuable insights into the behavior of steel links under seismic loading and help to inform the design and optimization of replaceable link systems for earthquake-resistant structures.
The main objective of the study was to understand how the short length ratio of the replaceable steel links affects their seismic performance. The short length ratio is defined as the ratio of the linked steel length (e) to the plastic flexural strength (Mp) divided by the plastic shear strength (Vp) of the steel links. The research found that the length ratio plays a significant role in the failure modes and energy dissipation capacity of the replaceable links. In particular, links with a length ratio of less than 1.6 exhibited shear-dominated behavior, while those with ratios between 1.6 and 2.6 showed a combination of shear and flexural behavior. Links with a ratio greater than 2.6 demonstrated primarily flexural behavior, which influenced their energy dissipation and inelastic deformation capacity.
The experimental results showed that all tested specimens exhibited stable and full hysteretic responses. This indicates that the steel links performed well in terms of their ability to dissipate energy during seismic events. The steel links demonstrated a large inelastic deformation capacity, which is crucial for absorbing seismic energy and reducing the overall damage to the structure. The researchers also observed two main types of failure modes: shear failure and bending-shear failure. These failures were accompanied by various damage features, including web-to-stiffener weld tears, web buckling, flange-to-end plate weld tears, and flange buckling.
To further validate the experimental findings, the researchers used nonlinear finite element models to simulate the behavior of the test specimens. The FEMs, created using ABAQUS software, provided additional insights into the load-deformation curves, initial stiffness, and stress development in the steel links. The numerical results were in good agreement with the experimental observations, which helps to confirm the accuracy of the model and its potential use in designing and optimizing replaceable steel link systems for real-world applications.
One of the key advantages of using replaceable steel links in building structures is the ability to quickly restore the building’s functionality after a major earthquake. Unlike traditional frame structures, where extensive repairs or even rebuilding may be necessary, systems with replaceable links allow for the rapid disassembly and replacement of damaged components. This can significantly reduce downtime and costs associated with repairs, ensuring that buildings are available for occupancy in the shortest possible time. The use of replaceable steel links, therefore, offers an efficient solution to the problem of structural damage and occupancy loss following seismic events.
The study’s findings are significant for the development of earthquake-resilient structures, as they provide a better understanding of how short length ratios impact the performance of replaceable steel links. By focusing on optimizing these ratios, engineers can design systems that maximize energy dissipation and minimize the likelihood of non-ductile failure during seismic events. The research also emphasizes the importance of using materials and designs that enable quick recovery, which is critical for both the economic and social aspects of earthquake recovery.
In summary, the research on replaceable steel links provides important insights into their seismic performance, failure modes, and energy dissipation capabilities. With the increasing demand for earthquake-resilient buildings, this technology offers a promising solution for reducing structural damage and enabling the rapid return of buildings to occupancy. By continuing to refine and optimize these systems, the construction industry can move closer to achieving the goal of creating buildings that are not only safe and durable but also capable of withstanding the forces of nature and recovering quickly after an earthquake.
