Steel plate shear walls (SPSWs) offer good energy dissipation capability when subjected to seismic forces as a robust lateral load resisting structure. This research investigated the cyclic behaviors of innovative infill web-strips (IWS-SPSW) and conventional unstiffened steel plate shear (USPSW) experimentally and numerically. As a result, two specimens of a 1:3 scale three-story single-bay IWS-SPSW and USPSW were fabricated and tested under cyclic lateral loading. Rigid moment-resistant connections were used for the steel plate shear wall beam-column connection. The steel shear walls with infill web strips showed high ductility and less shear load-bearing than the USPSW. The hysteresis results showed that the IWS-SPSW had high energy dissipation with no severe beam-columns damages. On the other hand, the USPSW displayed severe post-buckling, infill panel cracks, and first-floor column damages. Moreover, the IWS-SPSW shear strength did not fall in the test specimen beyond 2.5% average story drift, where the structure exhibited great seismic behavior. FE models were created and validated with experimental data. It has been proven that the infill web-strips can affect an SPSW system’s high performance and overall energy dissipation. From a parametric study, the material features of the infill web-strips, such as steel strength and thickness, can enhance the system’s impact even more.

L-shaped concrete-filled steel tubular (CFST) columns represent a valuable structural element with an L-shaped cross-section, primarily employed in the corner columns of framed structures. These columns offer several advantages, including space efficiency by avoiding column protrusion, robust mechanical properties, high load-bearing capacity, ductility, and efficient utilization of internal building space. This article presents the outcomes of an experimental investigation into the seismic behavior of L-shaped CFST columns. The experimental study investigated the seismic performance of nine L-shaped CFST columns while considering different cross-sectional dimensions, their combinations, and varying levels of confinement. The results obtained from this study indicate that L-shaped CFST columns possess favorable seismic performance characteristics. However, there exists the potential for significant improvement by modifying certain parameters. Enhancements in seismic performance were observed when increasing the cross-sectional dimensions of the column and the length of its legs. The use of steel tubes and the provision of adequate confinement also demonstrated notable benefits. Moreover, the better arrangement of steel tubes within the column positively influenced seismic performance. These findings can potentially inform and enhance the design of L-shaped CFST columns, rendering them more resilient to seismic forces.

In this study, novel cross-shaped concrete-filled steel tube (CFST) and steel tube (ST) columns were developed. CFST columns have a high load-carrying capacity and excellent performance under seismic conditions, and the construction process is fast. In order to investigate the axial load bearings and failure mechanisms, six specimens of CFST and ST columns were tested under the axial load. Three different forms of CFST were employed in this study; one was an ordinary cross-shaped CFST (OC-CFST), while the other two were executed with significant inner changes; namely, stiffeners cross-shaped CFST (SC-CFST), and multi-cell cross-shaped CFST (MC-CFST) filled with concrete. The other group has the same OC-ST, SC-ST, and MC-ST, but these test subjects were without filled concrete. Through discussion of the failure mechanism, load displacement and load strain correlations are determined. The effects of parameters on ultimate resistance, failure pattern, and ductility index were studied. The axial load-carrying performance of the cross-shaped CFST columns was 75–80% better than that of ST columns; and each ST column displayed cooperative behavior. The finite element model (FEM) was simulated, and the outcomes of the experiments were used to validate it. The load–displacement relationships were established using parametric analysis. Existing design standards were used to calculate CFST column loading capacity. Finally, mathematical formulas were improvised to determine the ultimate load of the cross-shaped CFST column.

A significant portion of the global building stock, particularly in seismically active regions, remains vulnerable to earthquakes because of outdated design codes, insufficient seismic considerations, and material aging. Conventional retrofitting methods are often inadequate for addressing the dynamic complexities associated with seismic loading. Seismic isolation (SI) offers a superior alternative by decoupling structures from ground motion, significantly reducing inertial forces, and enhancing the protection of structural and non-structural components. This study provides a comprehensive analysis of state-of-the-art SI techniques for retrofitting existing structures, focusing on the underlying principles of SI such as period elongation and energy dissipation. It also explored common SI system types, including elastomeric bearings (NRB, HDRB, and LRB) and sliding systems (FSB and FPS), and presented a systematic retrofitting procedure. Placement strategies (base vs. mid-story isolation) are discussed, and various international case studies (e.g., USA, Italy, China, and Japan) are examined to highlight the successful implementation and performance benefits. Despite its proven effectiveness, SI faces challenges including higher initial costs than conventional methods, technical complexities related to installation and foundation adaptation, long-term durability concerns, and regulatory barriers to its use. The review concludes by identifying emerging trends and future research directions, such as the development of advanced materials (e.g., SMAs, FREIs, and sustainable alternatives), integration of smart adaptive systems using AI and SHM, advancements in performance-based design, and expansion of applications to address climate resilience and nonstructural protection. This synthesis aims to bridge the gap between theoretical advancements and practical applications, thereby offering valuable insights into enhancing the seismic resilience of existing built environments.

Steel plate shear walls (SPSWs) are a robust lateral load resistance structure because of their high ductility and efficient energy dissipation when subjected to seismic loads. This research investigates the seismic performance of an innovative infill web strip (IWS-SPSW) and a typical unstiffened steel plate shear wall (USPSW). As a result, two 1:3 scale specimens of an IWS-SPSW and USPSW with a single story and a single bay were built and subjected to a cyclic lateral loading methodology. In the prototype, semi-rigid end-plate connectors for the beam-to-column connections were utilized. The test result of IWS-SPSW showed outstanding ductility and shear load-bearing capacity without cracks or damage. Additionally, the IWS-SPSW exhibited strong energy dissipation without substantial beam-column connection distortion. USPSW showed excellent shear load-bearing capacity, low ductility, extensive infill plate corner tearing, and large infill web plate cracks. The FE models were developed and verified against experimental data. It has been shown that the infill web strips can affect the high performance and overall energy dissipation of an SPSW system. In addition, a parametric study was conducted to investigate the infill web strip material properties, such as steel strength and thickness, that can significantly enhance the system’s seismic performances.

To address the poor characteristics of low strength and poor toughness in phosphogypsum-based construction material, this study investigates the influence of different diameters, lengths, and dosages of polyvinyl alcohol (abbreviated as PVA) fibers on the workability and mechanical properties of phosphogypsum-based construction material. The results show that as the length and dosage of PVA fibers increase, the flowability of the slurry gradually decreases, and the setting time also shortens. With an increase in the diameter of PVA fibers, the rate of decrease in flowability slows down, and the rate of shortening of setting time also gradually slows down. Moreover, the inclusion of PVA fibers significantly improves the mechanical strength of the specimens. When PVA fibers with a diameter of 15 μm, length of 12 mm, and dosage of 1.6% are used, the phosphogypsum-based construction material reinforced with PVA fibers exhibits optimal performance. Under this mixing ratio, the strength values of the specimens for flexural strength, bending strength, compressive strength, and tensile strength are 10.07 MPa, 10.73 MPa, 13.25 MPa, and 2.89 MPa, respectively. Compared to the control group, the strength enhancements are 273.00%, 164.29%, 15.32%, and 99.31%, respectively. SEM scanning of the microstructure provides a preliminary explanation for the mechanism of how PVA fibers affect the workability and mechanical properties of phosphogypsum-based construction material. The findings of this study can provide a reference for the research and application of fiber-reinforced phosphogypsum-based construction material.