Journal of Structural Engineering

Effectiveness of metaheuristic algorithms in optimization of CFDST short columns

2025-04-02T11:05:23+00:00

Concrete-Filled Double Steel Tubular (CFDST) columns, a subclass of composite members, are increasingly utilized in modern construction due to their superior structural performance, including higher strength-to-weight ratio, stiffness, fire resistance, and durability compared to traditional reinforced concrete (RCC) and steel structures. While the optimization of CFDST columns has been widely studied using statistical methods like Response Surface Methodology (RSM), this study focuses on applying advanced metaheuristic algorithms for optimization. A comparative evaluation of the Algorithm (GA), Particle Swarm Optimization (PSO), and Jaya Algorithm (JA) is conducted to optimize the axial load capacity of CFDST columns by fine-tuning key design parameters. The optimization objective is to maximize axial load capacity, which serves as the fitness function in the algorithms. An empirical equation representing the axial load capacity is used as the objective function.The comparative analysis demonstrates that metaheuristic algorithms are efficient and straightforward for optimizing CFDST columns. Among the three, the JA outperforms the others, achieving faster convergence and more consistent results across various population sizes and generations. PSO also exhibits faster convergence than GA, though JA remains the most robust and reliable. The study observes that the axial load capacity of the columns increases by 4.17%, 13.9%, 1.16%, and 10.81% for the considered series of specimens utilizing the same or fewer geometric values of key design components. These findings highlight the potential of metaheuristic algorithms in enhancing the design efficiency of CFDST columns for modern structural applications.

Vibration analysis and testing of magnetorheological fluid damper for transtibial prosthetic limb

2025-04-02T11:05:23+00:00

The damping characteristics of a healthy limb change throughout the gait cycle. However, for transtibial amputees who are wearing mechanically passive damping prostheses, the lack of ability to change the damping values might expose them to injuries and health problems during the impact of heel strike. The use of magnetorheological fluid damper in prosthetic limb, which provides a wide dynamic range, seems to be able to prevent these conditions from taking place, due to its response to the magnetic field. In this work, the vibration characteristics of a transtibial prosthetic limb with a magnetorheological (MR) fluid damper have been numerically analyzed and experimentally investigated. A simplified single-degree-of-freedom model has been developed to represent the transtibial prosthetic limb with the damper. The model is then utilized to analyze the response of the prosthetic limb along with the damper when subjected to impact, with and without semi-active control, numerically. The MR fluid damper and attachments to transtibial prosthetic limb have also been tested with impulse excitation to obtain its response with and without semi-active control. Finally, the numerical and experimental results have been compared to show the increase in efficiency of the damping of vibrations experienced during the heel strike of the gait cycle while using the semi-actively controlled magnetorheological fluid damper in the transtibial prosthetic limb.

Faury’s particle packing concept for the efficient design of steel fiber reinforced concrete mixes to evaluate the compressive strength

2025-04-02T11:05:23+00:00

It is very well known that the particle packing density has significant effect on the performance of concrete. There are numerous particles packing models such as Abram, Slater and ACI2000-I, Bolomey, Feret and Faury and modified Faury to address various aspects of particle packing. In the present study, the concepts of the above-mentioned models were used to derive the best proportion of fine aggregate and coarse aggregate for conventional concrete (M35 grade) and steel fiber reinforced concrete (0.5%, 1.0% and 1.5% of volume fraction). Faury’s original model has been updated to suit for any concrete mix to arrive at improved properties. The framework consists of (i) determination of targeted strength and workability by using the cement, fine and coarse aggregate, void volume, void index, w/c ratio, volume of solids required for Abram’s model, Slater model, ACI 2000-I model, Bolomey model and Feret model (ii) generation of Faury’s curve with and without cement (iii) determination of solid content (iv) verification of compaction factor considering the effect of fibers and finally (v) mix design. By using the mix design obtained through Faury’s model, compressive strength has been determined and found that the strength is higher about 10 to 18% compared to the strength obtained conventional concrete.

Characterization studies on eco-friendly grout materials

2025-04-02T11:05:24+00:00

Grout is a dense fluid that is used to fill the gaps or used as reinforcement in existing structures. Over the last few decades, grouting technology (the use of grouts) has grown into one of the disciplines in the engineering field. The objective is to study the performance of the developed grout materials for joints of precast structural components for low cost housing with the replacement of additives or admixtures by using different industrial by-products such as Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) as eco-friendly grout materials. Generally, in grout materials, shrinkage is the major concern, and to overcome this difficulty in the developed grout mix, an expansive material, namely bentonite, is introduced. Various studies, such as, Particle size analysis, heat of hydration, compressive strength, water absorption, and shrinkage tests on the developed grout mixes were conducted. The result of this studies derives the characteristics of the developed grout mix. To substantiate the obtained results, the qualitative and quantitative analyses, such as X-ray fluorescence (XRF), thermogravimetric analysis and differential thermogravimetric analysis (TGA/DTA), and scanning electron microscopy, are also carried out to determine the behaviour of cementitious grout which has been compared with available commercial grouts.

Shear behavior of deep beam with web openings and reinforced with strut reinforcement: a numerical study

2025-04-02T11:05:24+00:00

This study aims to predict the shear behavior of Deep Beams (DB) with web openings and reinforced by struts. ABAQUS Finite Element (FE) program was used to investigate the effects of the type, dimensions, number, and position of the opening, additional reinforcement in the same direction as the strut reinforcement (AS), and Additional Vertical and Horizontal reinforcements (AVH) around the web opening on the shear behavior of the DB. The FE study results showed that the web opening had a significant effect on the shear behavior of DBs reinforced with strut reinforcement, especially for DBs with rectangular opening cuts half of the strut reinforcement. As a result of web openings cutting half or all of the strut reinforcement, the shear capacity of the DB at supports must also be taken into account. The addition of AS improved the ultimate capacity of the deep beam with a small web opening area; otherwise, it showed an insignificant effect on the varying web openings. Adding AVH around the web openings for DBs with rectangular web openings cuts half of the strut reinforcement improved the ultimate capacity and load distribution at support close to the web opening. However, the square openings that cut off all the strut reinforcements had a minor effect. Different proposed equations were provided to predict both the shear strength of the strut with the web opening and the ultimate shear strength of DB with varying web opening cut full/half of the strut reinforcement. Both struts acting as columns and the suggested equations can be used to predict the design shear strength and ultimate capacity of deep beams with web openings and reinforced with strut reinforcement, according to a comparison with the ACI318 formula and the FE result.