Steel plate shear walls usually do not satisfy the strong-column weak-beam design criteria, leading to larger column sections. On the other hand, rigid frame structures are typically constructed in low-rise to mid-rise buildings built in locations prone to strong earthquakes due to their high flexibility and cost-effective solutions. Overcoming these restrictions to the SPSW system, this paper is dedicated to employing a semi-rigid connection that dissipates energy well and reduces the forces applied to the structure. By using a semi-rigid connection in an adjacent span to the SPSW, the actual flexural capacity of the beam end decreases and, subsequently, improves the performance of the structure in terms of the of the strong-column weak-beam criteria. Thereupon, the impact of the semi-rigid connections on steel frames with SPSWs as a sideway resisting system can be assessed by implementing a numerical study. In this paper, a new methodology for modelling semi-rigid joints is used considering five connections with different moment capacities. Moreover, the influence of three different circular diameters on the behavior of the perforated SPSWs was investigated. To fulfil these purposes, nonlinear dynamic analysis was conducted to assess the reliability of 5-, 10-, and 15-story frames resisted with SPSWs and semi-rigid connections subjected to actual ground motion records. A total of 45 frames were modelled and the obtained results were compared with reference benchmarks. The outcomes of the studies show good agreement with design building code requirements. In addition, the reliable performance of the structure under seismic loads is evaluated. According to the results of the parametric study, the presumed allowable drift leads to obtaining the optimum moment capacity of connection for each model and illustrates the applicability of a new structural system consisting of SPSWs and semi-rigid connections simultaneously.

Excessive consumption of natural aggregates in concrete production has led to resource depletion and environmental degradation. Recycled aggregate concrete (RAC) offers a sustainable alternative; however, its mechanical strength and durability are often inferior, especially under aggressive acidic environments such as acid rain. This study aims to enhance the mechanical and durability performance of RAC by combining magnetized water (MW) and nano-silica (NS) as complementary modification techniques. A total of 80 concrete mixtures were prepared with varying recycled concrete aggregate (RCA) contents (0–100%), NS dosages (0–6%), and MW exposure times (0–30 min). The specimens were exposed to simulated acid rain with pH values of 2.5, 4.0, 5.5, and 7.0 for 28, 56, and 90 days. Tests for compressive strength, electrical resistivity, mass loss, and sorptivity coefficient were conducted to evaluate performance. Results showed that the use of RCA reduced compressive strength by up to 25.4%, while increasing the acidity from pH 7 to 2.5 caused an additional 16.2–25.4% decline. However, the synergistic use of 6% NS and 30-min MW improved compressive strength by up to 14.1% compared to control specimens. Similarly, the combination of MW and NS enhanced electrical resistivity by 12–38% and reduced mass loss and compressive strength by 33% and 32%, respectively, demonstrating a denser and more durable microstructure. These findings confirm that MW and NS mitigate the detrimental effects of acid exposure and recycled aggregates by accelerating cement hydration, refining pore structure, and strengthening the interfacial transition zone. The optimal mix was found at 25% RCA, 6% NS, and 30 min MW exposure, which achieved superior performance across all parameters. It is concluded that the combined application of MW and NS offers a feasible and eco-efficient approach to improve the corrosion resistance and sustainability of RAC under acid rain. Future studies are recommended to investigate the long-term field performance of RAC in other aggressive media such as chloride environments.