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.

Phosphogypsum is an industrial by-product from the wet preparation of phosphoric acid. Phosphorus building gypsum (PBG) can be obtained from phosphogypsum after high-thermal dehydration. Improving the mechanical properties of PBG is of great significance to extending its application range. In this paper, PBG was modified by adding nano-CaCO₃. Specifically, this study, conducted on 0.25–2% nano-CaCO₃-doped PBG, tested effects on the fluidity, setting time, absolute dry flexural strength, absolute dry compressive strength, water absorption and softening coefficient of PBG, followed by its microscopic analysis with SEM and XRD. The experimental results showed that, with an increase in nano-CaCO₃ content, the fluidity and setting time of PBG-based mixes were decreased. When the content was 2%, the fluidity was 120 mm, which was 33% lower than that of the blank group; the initial setting time was 485 s, which was 38% lower than that in the blank group; the final setting time was 1321 s, which was reduced by 29%. Nano-CaCO₃ evidently improved the absolute dry flexural strength, absolute dry compressive strength, water absorption and softening coefficient of PBG to a certain extent. When the content was 1%, the strengthening effect reached the optimum, with the absolute dry flexural strength and absolute dry compressive strength being increased to 8.1 MPa and 20.5 MPa, respectively, which were 50% and 24% higher than those of the blank group; when the content was 1.5%, the water absorption was 0.22, which was 33% lower than that of the blank group; when the content approached 0.75%, the softening coefficient reached the peak of 0.63, which was 66% higher than that of the blank group. Doping with nano-CaCO₃ could significantly improve the performance of PBG, which provides a new scheme for its modification.

The preparation of fiber-reinforced phosphorus building gypsum composite materials (FRPGCs) is an important approach to enlarge the utilization of phosphogypsum resources. Through reinforcing phosphorus building gypsum (PBG) with basalt fiber (BF), this article probes into the effects of the length and fiber content of BF on the working performance and mechanical properties of basalt-fiber-reinforced phosphorus building gypsum composite materials (BRPGCs) and accesses the toughness of BRPGCs under bending loads using residual strength. The results showed that the addition of BF could significantly promote the mechanical properties of BRPGCs. However, due to the adverse effect of fibers on the working performance of BRPGCs, the fiber content was constrained. After adding 1.2% of 6 mm BF, the bending strength and compressive strength of FRPGCs reached maximum values of 10.98 MPa and 29.83 MPa, respectively. Under a bending load, BRPGCs exhibited an apparent ductile behavior. The P-δ curve presented five stages, with an evident phase of strength stability after cracking. A larger fiber content was conducive to the toughness of BRPGCs. When 1.6% of 6 mm BF was added, the residual strength of FRPGCs could reach 6.77 MPa.

Phosphogypsum is an industrial byproduct from the wet preparation of phosphoric acid. Phosphorus building gypsum can be obtained from phosphogypsum after high-thermal dehydration. This study aimed to analyze the influence of ball milling with different parameters on the strength of phosphorus building gypsum. In this paper, the absolute dry flexural strength and the absolute dry compressive strength of phosphorus building gypsum were compared under different mass ratios of material to ball, ball-milling speed, and ball-milling time, and the NSGM (1,4) model was applied to model and predict the strength of phosphorus building gypsum modified by ball milling. According to the research results, under the same mass ratio of material to ball and ball-milling speed, the absolute dry flexural strength and absolute dry compressive strength of phosphorus building gypsum firstly increased and then decreased with the increase in milling time. The NSGM (1,4) model established in this paper could effectively simulate and predict the absolute dry flexural strength and the absolute dry compressive strength of the ball-milling-modified phosphorus building gypsum; the average relative simulation errors were 12.38% and 13.77%, and the average relative prediction errors were 6.30% and 12.47%.