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CONTENTS
Volume 53, Number 4, November 25 2024
 

Abstract
Accurately predicting the bearing capacity of steel and concrete piles is a critical factor in the design and safety of deep foundations. This study presents a novel application of hybrid machine learning models, specifically Invasive Weed Optimization with Multilayer Perceptron (IWOMLP) and Harris Hawks Optimization with Multilayer Perceptron (HHOMLP), for enhancing the prediction of pile bearing capacity. These hybrid models integrate evolutionary optimization algorithms with neural networks, aiming to improve prediction accuracy by addressing the nonlinearities and complexities in pile-soil interaction. The study compares the performance of IWOMLP and HHOMLP against conventional machine learning methods such as Simple Linear Regression, Gaussian Processes, Random Forest, and others. The training and testing phases evaluate the models based on various error metrics, including R2, RMSE, MAE, and additional advanced metrics. The key innovation in this research lies in combining optimization techniques with neural networks, which significantly enhances the model's ability to predict complex geotechnical properties. The primary goal of this work is to develop a reliable, data-driven approach for accurate pile capacity prediction, providing a more precise tool for geotechnical engineers to improve decision-making in foundation design. Results indicate that the hybrid models, particularly IWOMLP, outperform traditional approaches, achieving higher R2 and lower RMSE values. This research demonstrates the potential of hybrid models to advance geotechnical engineering practices by delivering more accurate and reliable predictions.

Key Words
artificial neural network; driven piles; metaheuristic; ultimate bearing capacity

Address
Mesut Gör:Department of Civil Engineering, Engineering Faculty, Firat University, 23100 Elazig, Türkiye

Abstract
The fabric-reinforced cementitious matrix (FRCM) method is a structural strengthening method for RC structures supplementing the shortcomings of the fiber-reinforced polymer method in terms of heat resistance and suitability. As the FRCM is a strengthening method applied to the surface of RC structural members, its strengthening effect is determined based on the bond behavior between structural members and FRCM composites. In this study, six specimens were prepared for a double shear test to identify the bond behavior between FRCM and RC members. The main variables of the specimens were the number of fabric layers and the spacing between the fabrics. All the specimens exhibited the ultimate strength improvement of 61% to 337% compared to the control specimen depending on the number of fabric layers and the spacing between the fabrics, and the failure mode changed fracture after slip of fabric to debonding between the fabrics and cement matrix depending on the number of fabric layers. A bond behavior model is proposed modifying the existing bond mechanism to consider the number of fabric layers and the spacing between the fabrics. It also considers the interaction between the fibers in the weft direction and the cement matrix. The proposed model was validated for evaluating the bond strength of the FRCM with carbon fabric.

Key Words
bond mechanism; carbon fabric; double shear test; fabric reinforced cementitious matrix; strengthening method

Address
Yujae Seo:Architectural Convergence Laboratory of Industry-Academic Cooperation Foundation, Hankyong National University, Jungang-ro 327, Anseong, Gyeonggi 17579, Republic of Korea

Hyunjin Ju:School of Architecture and Design Convergence, Hankyong National University, Jungang-ro 327, Anseong, Gyeonggi 17579, Republic of Korea

Abstract
In order to study the seismic performance of the damaged steel concrete special-shaped beam-column joints reinforced by manually compacted ultra-high performance concrete (UHPC), cyclic hysteresis loading tests were carried on two profiled concrete beam-column joint specimens before and after the reinforcement. The failure mode, load carrying capacity, deformation, hysteresis curves, skeleton curves, strength degradation, stiffness degradation, and energy dissipation capacity of the specimens were compared before and after reinforcement. The results show that the bonding performance between UHPC material and ordinary concrete was very good. After UHPC reinforcement, the bearing capacity of the damaged joints can be basically restored to the intact state, and the energy-consuming capacity increased, but the stiffness degradation was obvious. It is recommended that when using UHPC for joint reinforcement, the effect of forming ring wrap in the joint area is better. The research conclusion can provide reference for the design and popularization of UHPC and has certain theoretical and practical value.

Key Words
manually compacted; profiled concrete shaped beam-column joints; repair and reinforcement; seismic performance; tra-high performance concrete

Address
Hu Aoxiang, Du Jing and Liao Xi:School of construction engineering, Shenzhen Polytechnic University, No. 7098 Liuxian Road, Shenzhen, Guangdong Province, P.R. China

Song Xiaofang:School of Architecture and Art Design, Henan Geology Mineral College, No. 51 Yongji Road, Zhengzhou, Henan Province, P.R. China

Abstract
The stability performance of the components in musical stringed instruments is crucial regarding sound quality and durability. In this framework, such stability is studied theoretically by the approach of numerical solution. Numerical method is used to analyze buckling of embedded sinusoidal piezoelectric beam. Smart beam is subjected to external voltage in the thickness direction. By considering the beam model of the structural elements of instruments, through proper development, the analysis develops more advanced deformation theories that can grasp these complicated behaviors of resonance and performance. The structure was modeled by sinusoidal shear deformation theory, and by using the energy method, the final governing equations were derived on the basis of the piezo-elasticity theory. Numerical methods used give an insight into the most important factors of influence that provoke stability loss of these components in different conditions of loading and vibration. The results are obtained also to illustrate how structural optimization and material properties affect the overall performance of a musical instrument, therefore giving guidelines on the enhancement of their acoustic features and durability.

Key Words
musical instrument; numerical solution; stability; theoretical framework

Address
Feng Wang:1)School of Music and Dance, Heze University, 274015, Shandong, P.R. China
2)Institute of International Education, New Era of University College, 43000 Kajang, Selangor, Malaysia

AH. Zaman-Pouri:Department of Civil Engineering, Islamic Azad University, Tehran, Iran

Abstract
This study develops Titanium (Ti) and Magnesium (Mg)-based nano-alloys to enhance the earthquake resilience of steel structures using machine learning (SVM) and sensor technology. Embedding Ti and Mg into steel at the nanoscale creates a lightweight, durable, and flexible material capable of withstanding seismic forces. Ti enhances tensile strength and flexibility, while Mg reduces weight, lowering seismic loads on buildings. The performance of these nano-alloys was assessed through shake table tests, cyclic load testing, and dynamic response testing, showing that nano-alloy-enhanced steel structures experienced 60% less displacement and 40% lower acceleration than traditional steel, demonstrating superior energy absorption and stress distribution. Fatigue tests revealed that the nano-alloy could endure 20,000 loading cycles, outperforming the 8,000 cycles of conventional steel. Integrated sensor technology, including strain gauges and accelerometers, provided real-time stress and deformation data, confirming the material's effectiveness in stress distribution and vibration damping. The SVM model optimized alloy composition, achieving 94% prediction accuracy in assessing seismic performance, highlighting the nano-alloys' durability and resilience. This study suggests that Ti and Mg nano-alloys could greatly improve earthquake-resistant construction.

Key Words
earthquake-resilient steel structures; Machine Learning (SVM); predictive maintenance and disaster mitigation; seismic energy dissipation; sensor technology; titanium-magnesium nano-alloys

Address
Xiaoping Zou: Sichuan Jinghengxin Construction Engineering Testing Co., LtdLu, zhou 646000, China

Gongxing Yan: 1)School of Intelligent Construction, Luzhou vocational and technical college, Luzhou 646000, China 2)Luzhou Key Laboratory of Intelligent Construction and Low-carbon Technology, Luzhou 646000, China

Khidhair Jasim Mohammed: Air Conditioning and Refrigeration Techniques Engineering Department, College of Engineering and Technologies, Al-Mustaqbal University, 51001 Hilla, Babylon, Iraq

Meldi Suhatril: Department of Civil Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia

Mohamed Amine Khadimallah: Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia

Riadh Marzouki: Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, 61413 Abha, Saudi Arabia

Hamid Assilzadeh: 1)Faculty of Architecture and Urbanism, UTE University, Calle Rumipamba S/N and Bourgeois, Quito, Ecuador 2)Institute of Research and Development, Duy Tan University, Da Nang, Viet Nam 3)School of Engineering & Technology, Duy Tan University, Da Nang, Viet Nam 4)Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600077, India 5)University of Calgary, Schulich School of. Engineering, Department of Geomatics. Engineering. Calgary, Alberta, Canada

José Escorcia-Gutierrez: Department of Computational Science and Electronics, Universidad de la Costa, CUC, Barranquilla, 080002, Colombia


Abstract
This paper investigates the utilization of composite columns achieved by incorporating four steel angles at the corners of columns, interconnected with transverse plates. The experimental program involves ten columns, varying slenderness ratio, angle thickness, and transverse reinforcement spacing to evaluate the effect of variable parameters on the load-carrying capacity, Failure modes and behavior of these type of composite columns. Also, The objective of this research is revised the analytical calculations from the different international codes/standards to test their reliability in predicting the load-carrying capacity of composite columns compared to experimental results. Next, using ANSYS and validated finite element method, a parametric analysis is carried out for cases under eccentric loading. According to results, Steel-angled composite columns perform better than regular columns, demonstrating increases in load carrying capability because of improved confined concrete within steel angles. As the thickness of the steel angles increased (reinforcement ratio increased from 2.91% to 4.75%), increasing load capacity to 28% and lowering axial and lateral displacements to 20% and 30%, respectively. There was a difference in the experimental and finite element ' load capacities at failure that ranged from (-3%) to (+6%). The effect of slenderness ratio in columns with eccentric load is clear that the load capacities of the slender columns are 10% less than those of the shorter ones when axial eccentric loads are taken into account according to parametric investigation. In addition, both AISC and ECP 205 included the slenderness ratio when estimating load capacity; however, AISC was less cautious than ECP 205. Both ACI 318 and ECP 203 neglect the slenderness ratio when calculating load capacity that ECP 203 understates while ACI 318 code overstates load capability.

Key Words
buckling; composite columns; confined concrete; ductility; load capacity; slenderness ratio; steel equal angles; welded connections

Address
Nehal M. Ayash, Ahmed H. Ali, Ahmed Abdellatif and Hala Mamdouh:Department of of Civil Engineering at Helwan University, Cairo, Egypt

Abstract
In the modern era, the world is grappling with unprecedented challenges posed by environmental pollution. International agencies are urging scientists and material engineers to seek out green materials and structures as solutions to this problem. Composites derived from renewable sources, such as plant-based and vegetable fibres, are increasingly being utilized in the interior composite components of automobiles, aircraft, and building construction. This work introduces an improved Single Fibre Tensile Test (SFTT) for natural fibres, which are often irregular in shape and non-uniform along their length. Conventional methods, which determine the fibre cross-section by measuring the diameter using optical microscopy, yield inaccurate properties with large standard deviations (SD). The proposed new SFTT method, based on standards set by the American Society of Textile Manufacturing, provides a more accurate assessment of the mechanical performance of fibres. Using this approach, the tensile strength of various single fibres, yarns, and fabrics was measured with an SD of less than 8%.

Key Words
composite; fabrics; fibre yarns; mechanical testing; natural fibres; SFTT; standard deviation

Address
Ravi Kumar, Shaik M. Subhani and Bonda A.G. Yuvaraju:School of Mechanical Engineering, SASTRA Deemed University, Thanjavur, Tamilnadu 613402, India

Abstract
In this paper, a new refined higher-order shear deformation theory "RHSDT" is presented for the flexure and free vibration analysis of functionally graded (FG) plates. The main feature of this model is that it relies on a simple and optimized 2D displacement field with only two unknown variables, even less than other shear deformation theories that involve three or more unknown variables. The current theory considers a hyperbolic non-linear shape function for satisfying exactly the zero shear stress conditions on the external plate surfaces without using a shear correction factor. The mechanical properties of FG plates are assumed to vary continuously through the thickness direction according to a power-law distribution "P-FGM" and an exponential-law distribution "E-FGM". The governing equations and boundary conditions of FG plates are derived by implementing Hamilton's principle. To verify the accuracy of the present theory, the analytical results computed for simply supported FG thick plates via the Navier-type technique are checked with those obtained by other shear deformation models and 3D elasticity solutions regarded in the literature. Additionally, the impact of significant parameters on the results of mechanical stresses and natural frequencies is discussed.

Key Words
2D displacement field; flexure; free vibration; functionally graded plates; high-order shear deformation theory

Address
Kada Draiche:1)Department of Civil Engineering, University of Tiaret, BP 78 Zaaroura, 14000 Tiaret, Algeria
2)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria

Emrah Madenci:1)Necmettin Erbakan University, Department of Civil Engineering, 42090, Konya, Turkey
2)Department of Technical Sciences, Western Caspian University, Baku 1001, Azerbaijan

Ibrahim Klouche Djedid:1)Department of Civil Engineering, University of Tiaret, BP 78 Zaaroura, 14000 Tiaret, Algeria
2)Laboratoire Matériaux et Structures (LMS), University of Tiaret, Algeria

Abdelouahed Tounsi:1)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran,
Eastern Province, Saudi Arabia 3)Department of Civil and Environmental Engineering, Lebanese American University, 309 Bassil Building, Byblos, Lebanon

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