Articles
Engineering Structures (18737323)336
The recently developed metallic-yielding pistonic (MYP) damper is a novel passive control system. It consists of a set of rectangular yielding plates under pure-bending loading conditions. The developed device generally performs as a tension/compression element with rigidity and stability in other directions. In this study, a step-by-step procedure is presented for the design of the structures controlled by this damper under severe earthquakes. The main design objective of this procedure is the perfect seismic protection of the combined control-structure based on the fulfillment of two criteria including fuse-like performance and control sustainability. The first criterion preserves the elastic behavior of the controlled structure (which is defined as the perfect structural protection) under severe earthquakes and the other one is required to be met for the stability of the control system. The study is followed by examination of the procedure through seismic analyses of four 5–20 story moment-resisting buildings as examples of its application. From the obtained results, it was observed that the developed procedure is able to meet all design control objectives for multi-story buildings with acceptable accuracy without requiring any complicated numerical control-structure modeling and nonlinear dynamic analyses. Moreover, the controlled structures experience seismic responses significantly decreased by 67–56 %, 60–46 % and 79–70 % respectively for the maximum lateral drift, shear force and residual drift in average for the stories from the shortest to the tallest structure. © 2025 Elsevier Ltd
Journal of Constructional Steel Research (0143974X)235
This study offers a 3D finite element modeling (FEM) and parametric analysis of a novel extended endplate beam-to-column semi-rigid deconstructable external composite joint (DECJ) under cyclic loading. This innovative DECJ is created by connecting the precast geopolymer concrete slab to the top flange of a steel beam using bolted shear connectors, and inserting threaded central reinforcing bars into the column flanges to enhance the demountability of the entire system. The FEM was developed using ABAQUS software and verified against the experimental study results to analyze the structural behavior and failure modes of the proposed DECJ system. The study investigates the effect of various parameters, including the diameter of bolted shear connectors, the degree of shear connection, the ratio of central reinforcing bars, the thickness of the endplate, the thickness and strength of the geopolymer concrete slab, and the bolt diameters of the connection zone. The findings suggest that to prevent the failure of bolted shear connectors, the optimal shear connection degree of approximately 73 %–90 % and the concrete slab thickness of 80-120 mm should be maintained. Additionally, the central reinforcing bar ratio is preferred to be around 0.98 % to avoid the failure of shear connectors and reinforcing bars. Furthermore, the ratio of endplate thickness to connection zone bolt diameter should be between 0.64 and 0.82 to reduce the fracture risks of connection zone bolts. Finally, a new predictive equation is proposed to determine the plastic moment capacities of DECJs with precast concrete slabs, demountable bolted shear connectors, and demountable central reinforcing bars under cyclic loading. © 2024
Case Studies in Construction Materials (22145095)22
The significance of finding industrial waste solutions in the construction industry plays a crucial role in the quest for environmental conservation. To reduce the carbon footprint, this research has focused on developing solutions. This study assesses the mechanical properties of water-cured alkali-activated slag concrete (AASC) prepared using a one-part activator, where the dry alkali activator is pre-mixed with slag before water addition. The mix is then reinforced with three types of steel fibers, namely deformed steel fibers (DSF), recycled tire steel fiber (RTSF), and hybrid steel fiber (HSF) at varying volume fractions (0.5 %, 0.75 %, and 1.0 %). Numerous characteristics, including workability, compressive strength, flexural strength, splitting tensile strength, flexural toughness, and SEM observations in short-term, and stress-strain response under uniaxial compression, modulus of elasticity, peak strain and energy absorption in long-term were assessed. According to the test results, compressive strength was largely unaffected by fiber addition, with DSF at 1 % volume (DSF1) achieving the highest strength (58.51 MPa at 28 days). Conversely, optimal compressive strength for RTSF was observed at 0.5 % volume. On the other hand, the concrete mixes' splitting tensile, and flexural strengths increased with the addition of steel fibers achieving maximum values at 1 % DSF. The addition of steel fibers transformed the stress-strain response of one-part AASC mixes from brittle to ductile, with HSF specimens at 1 % volume (HSF1) exhibiting a 50 % increase in strain related to peak stress compared to the reference. Remarkably the HSF1 mix achieved a 421 % increase in toughness at 365 days compared to the reference mix. The DSF1 mix at 28 days and HSF1 at 365 days achieved the highest energy absorption capacity. Overall, the inclusion of 1 % DSF, RTSF, and HSF fibers enhanced the mechanical properties of one-part AASC, with DSF providing the most significant improvements at 28 days. © 2024 The Authors
