Research Article
A Comparative Study on Seismic Strengthening of Reinforced Concrete Beam–Structural Wall Joints Using External Stiffeners Plate, Basaltic Fiber and CFRP
Yosef Mulugeta*
,
Utino Worabo
Issue:
Volume 10, Issue 2, June 2026
Pages:
34-47
Received:
5 January 2026
Accepted:
26 January 2026
Published:
10 April 2026
Abstract: The existing structure might not have enough seismic resistance capacities due to construction errors, design by old building design codes (EBCS 1995), deterioration, and building function changes. To increase the seismic resistance capacity of Reinforced Concrete (RC) structures, many studies recommend different strengthening methods. Those strengthening methods have different costs, strengthening capacities, and availabilities. To identify the best, strengthening methods it needs further investigations. Most previous studies were conducted on the detailed application of individual strengthening applications. There are no previous studies that have done a comparative study on the seismic strengthening of reinforced concrete beam–structural wall joints using external stiffener plates, Basaltic Fiber Reinforced Polymer (BFRP), and Carbon Fiber Reinforced Polymer (CFRP). The main aim of this study is a comparative study on the seismic strengthening of reinforced concrete beam–structural wall joints using an external stiffener plate, BFRP and CFRP. The experimental work presented in the literature was used for validation of finite element analysis to ensure the accuracy of developed finite element models and further investigations. The numerical investigation of a comparative study on the seismic strengthening of reinforced concrete beam–structural wall joints using external stiffener plates, basaltic fiber, and CFRP has been done with the comparison of load resistance capacities. The numerical study will be done using ANSYS 22R1 mechanical APDL nonlinear software program. The finite element analysis result shows that, for both CFRP and BFRP from 0°, 45° & 90° layer orientations of CFRP strengthening methods, 90° CFRP layer orientation shows better improvement of ultimate load resistance capacity. The 90° layer orientation strengthening layout increased the load-carrying capacity of the beam-shear wall connection by 30% and 26.4% for CFRP and BFRP respectively. For both CFRP and BFRP strengthening mechanisms with 90° orientation, three number of layers and 90°, 90°& 90° configuration best fiber lay out for strengthening of beam – shear wall joint. From the three beam -shear wall strengthening mechanisms of stiffener plate, CFRP and BFRP, the stiffener plate shows better performance. The stiffener plate increases the lateral load resistance capacity of the existing beam- shear wall joint by 37% - 66%.
Abstract: The existing structure might not have enough seismic resistance capacities due to construction errors, design by old building design codes (EBCS 1995), deterioration, and building function changes. To increase the seismic resistance capacity of Reinforced Concrete (RC) structures, many studies recommend different strengthening methods. Those streng...
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Research Article
A Multi-parameter Optimization Framework for Casting Quality: Beyond Riser Geometry
Joni Arif*,
Andrian Maulana
Issue:
Volume 10, Issue 2, June 2026
Pages:
48-61
Received:
27 April 2026
Accepted:
8 May 2026
Published:
10 June 2026
DOI:
10.11648/j.ajmme.20261002.12
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Abstract: Casting defects such as shrinkage porosity, hot tearing, and misruns continue to impose significant economic burdens on foundry industries worldwide, with rejection rates for complex castings sometimes exceeding 15%. While riser geometry has traditionally been the primary lever for defect control, emerging evidence suggests that a holistic, multi-parameter approach encompassing pouring temperature, mold permeability, alloy composition, and solidification rate can substantially outperform single-variable optimization strategies. This study introduces a comprehensive Multi-Parameter Optimization Framework (MPOF) for casting quality control that integrates Taguchi design-of-experiments, finite-element solidification modeling, and response surface methodology to simultaneously optimize nine independent process variables. A total of 81 experimental runs were conducted using an aluminum–silicon alloy (A356) in green-sand molds, with porosity index, surface roughness Ra, and Vickers hardness as quality metrics. Results indicate that pouring temperature (contribution ratio: 28.3%) and mold permeability (21.7%) exerted the greatest influence on porosity formation, while alloy silicon content (19.4%) most significantly affected hardness distribution. Optimal parameter combinations achieved a porosity index reduction of 63.5% relative to baseline conditions and improved ultimate tensile strength by 18.2%. The MPOF revealed complex interaction effects between cooling rate and gating system design that had previously been masked in single-variable studies. Validation trials confirmed model predictions with a mean absolute error below 4.1%. This framework provides foundry engineers with a systematic, data-driven methodology for quality optimization that transcends the conventional focus on riser geometry alone, offering applicability to diverse alloy systems and mold configurations.
Abstract: Casting defects such as shrinkage porosity, hot tearing, and misruns continue to impose significant economic burdens on foundry industries worldwide, with rejection rates for complex castings sometimes exceeding 15%. While riser geometry has traditionally been the primary lever for defect control, emerging evidence suggests that a holistic, multi-p...
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