International Journal of Structural Engineering (8 papers in press)

Regular Issues

• Soil-structure interaction using equivalent support stiffness in response of cooling towers  
  by Sachin R. Kulkarni 
  Abstract: The idealisation of support boundary conditions for the hyperbolic shape cooling tower shell has significant influence on static and dynamic response of the shell. The sensitivity of the support boundary conditions on the static response of the cooling towers is investigated. Studies on soil-structure interaction (SSI) on static response of cooling tower shell available in the literature are largely focussed on meridional and hoop forces for a particular value of soil stiffness under consideration. The current study focuses on effect of SSI on static response of hyperbolic cooling tower shell for the practical range of soil stiffness values. It is observed that with the decrease in soil stiffness, the vertical displacement of tower shell increases with no significant change in meridional and hoop forces, indicating rigid body displacement rather than deformation. The applicability of equivalent support stiffness concept developed by the authors earlier is investigated to evaluate the static response of the shell on column supports including SSI. The study also includes the redistribution of membrane forces and column forces due to loss of column support at a location.
  Keywords: boundary condition; soil-structure interaction; SSI; static response; equivalent support stiffness.
  
  
• Experimental investigation on the compressive behaviour of concrete confined by glass fibre geogrid mesh  
  by Seyed Shaker Hashemi, Seyedahmadreza Rezaei, Mohsen Matin, Mohammad Vaghefi 
  Abstract: The study aims to experimentally investigate glass fibre reinforced geogrid (GFRG) mesh confined concrete behaviour. The utilised mesh in this study has openings of 20 mm, weighing 240 gr/m2, and a tensile strength of 60 KN/m. For this research, 42 standard cylindrical concrete specimens with a diameter of 150 mm and a height of 300 mm were constructed. These specimens were created in both unconfined and confined states, with GFRG mesh confined concrete. The specimens had varying hoop layer counts (1, 1.5, and 2 layers) with concrete covers of 10 and 20 mm. After fabrication and curing, the specimens were tested to evaluate their ductility, energy absorption, and compressive strength under various confinement layers and concrete covers. The results revealed that the incorporation of GFRG mesh confined concrete to induce confinement leads to a slight decrease of approximately 3% in confinement strength at 28 days. Ductility and post-cracking behaviour improved, leading to a 20% increase in energy absorption.
  Keywords: confined concrete; compressive behaviour; glass fibre reinforced geogrid; GFRG.
  
  
• Analysing the dynamic behaviour of a functionally graded beam subjected to a moving force under varied boundary conditions  
  by Mohamed Bouamama, Abbes Elmeiche, Azzeddine Belaziz, Abdelhak El Hannani, Hammoudi Abderazek 
  Abstract: In this article, the dynamics of both free and forced vibrations in material gradient beams (FGM) are explored by examining various physical and geometrical parameters under different boundary conditions The beam’s material properties feature an upper ceramic facet and a lower metal facet, which vary continuously through the thickness direction following a power law function (P-FGM) The external force is determined by a moving concentrated force, with or without considering the inertial effects of the transient load The governing differential equations are derived through a theoretical formulation using the logarithmic shear function of the beam (LSDBT) For the study of free vibrations, an analytical method is employed, which involves separating variables and applying the modal approximation method of Rayleigh-Ritz Numerical calculations are used to analyze forced vibrations, utiliSing Newmark’s temporal method. A parametric investigation is conducted on different beam configurations to assess the impact of various parameters on the dynamic responses of the beam. The results from our proposed model demonstrate a strong agreement with the findings in the literature, validating the effectiveness and accuracy of our approach.
  Keywords: FGM beams; free vibration; forced vibrations; moving force; eigenfrequencies; LSDBT.
  
  
• Critical thickness of filler material for effective crack-filling at different water heads in dams  
  by Bilal Ahmed Malik, Abdul Qayoom Dar, Mohd. Akbar Lone 
  Abstract: Crack filler material is usually provided in dams susceptible to cracking due to seismic activity, uneven settlement, and various other reasons. This study has been done to find the minimum thickness of the filler material needed for necessary crack-filling action. The 20 mm piped core was tested for water heads varying from 1 m to 5 m and filler material having thicknesses of 16 cm to 8 cm. Experimental results indicated that when the head of the water is increased, the critical thickness of filler material required for effective crack-filling also increases. Based on trial results, an equation that offers the variation of the required thickness of filler material with a water head has been proposed. The current study recommends that filler material of varying thickness should be provided with a minimum thickness of 0.11 times the design water head at the bottom of the dam.
  Keywords: dams; cracking; crack-filling; filler material; critical thickness; water head.
  DOI: 10.1504/IJSTRUCTE.2024.10063566
   
  
• Assessing of the punching capability of developed slab-column connections in precast concrete flat slabs  
  by Ahmed A. Nasr, Yehia A. Hussein, Nabil A.B. Yehia, Khaled F. El-Kashif 
  Abstract: Punching capacity and failure behaviour of developed slab-column connections of precast concrete structures are investigated in this work. The experiments were implemented on the interior column of a residential flat slab, using four connections of full scale compared to the prototype connection. The configuration and erection methods are regarded the most important parameters, as they are classified as concrete corbel, steel corbel, dowels, Indo, and prototype. The results revealed that, the ultimate loads attained by the concrete corbel connection, steel corbel connection, and dowels connection exceeded the load attained by the prototype connection. Furthermore, increasing the axial loading area increases punching failure resistance and load capacity. Additionally, the steel reinforcement is essential since it participates in punching opposition. Lastly, it was reached that dowels and concrete corbel connections can be used for only one story, while the steel bracket, and Indo connections can be utilised on multiple slab floors.
  Keywords: punching shear; load capacity; precast concrete structures; slab column connection; flat slab.
  DOI: 10.1504/IJSTRUCTE.2024.10063561
   
  
• Damage detection for long-span bridges through support vector machine, wavelet transform, and multivariate empirical mode decomposition  
  by Rouzbeh Doroudi, Seyed Hossein Hosseini Lavassani, Mohsen Shahrouzi 
  Abstract: Structural health monitoring (SHM) is crucial for long-span bridges, yet the challenge lies in handling vast data and precise feature selection. In this study to address this, observer-teacher-learner-based optimisation is used to fine-tune support vector machine parameters. The wavelet transform (WT) is employed to effectively filter noise and unwanted frequencies from structural acceleration responses. Further, acceleration responses are decomposed into intrinsic mode functions (IMFs) using multivariate empirical mode decomposition (MEMD). These IMFs are then utilised for classification with statistical features as required data for damage identification through optimal SVM. Data from Tianjin Yonghe Bridge in China validates the model's ability to accurately detect damage, its location, and severity. This approach demonstrates a practical method for damage detection in large-scale bridges by extracting statistical time-domain features through WT and MEMD, presenting a valuable contribution to the SHM field.
  Keywords: structural health monitoring; SHM; statistical time-domain features; bridge health assessment; damage classification; damage severity; feature extraction.
  DOI: 10.1504/IJSTRUCTE.2024.10063564
   
  
• State-of-art studies on applications of magnesium alloys in construction industry  
  by Yogesh Iyer Murthy 
  Abstract: Magnesium alloys have gained worldwide interest due to their superior mechanical qualities, low density, and recyclable capabilities. The current effort intends to analyse and evaluate the prospective uses of magnesium alloys in the building sector, which can result in a major contribution to sustainable construction because to their high recyclability. The mechanical characteristics of magnesium and its chosen alloys, which are extensively employed in structural applications, are being studied. The properties of AM60A, AM60B, AZ91A, AZ91C, AZ91D, AE42, and WE43 are discussed. Particularly, the ultimate yield strength, true stress strain curve, and tensile creep vs. elongation are compared to other metals used in the construction sector, such as steel and aluminium. The impact of commonly used alloying elements with Mg is also summarised. Based on this study, sustainable applications of magnesium alloy in the building sector for both structural and non-structural applications have been identified.
  Keywords: sustainability; magnesium alloys; mechanical properties; structural applications; non-structural applications.
  DOI: 10.1504/IJSTRUCTE.2024.10063565
   
  
• Masonry infill walls in framed buildings: practical recommendations for minimising the detrimental interactional effects  
  by Vahid Mokarram, Mohammad Reza Banan, Mahmoud Reza Banan, Saeed Hatami 
  Abstract: The aim of this study is to improve the seismic performance of framed buildings with masonry infill walls (MIWs) by providing practical recommendations for their design. Finite element models validated against experimental data are used to investigate the effects of different factors, such as the aspect ratio, gap size and location, and steel plate connectors, on the in-plane (IP) and out-of-plane (OOP) behaviour of MIWs. Optimal gap configurations for MIWs are proposed to reduce their interaction with steel frames until large deformations occur. A simple method of stiffening MIWs with steel plate connectors is suggested to ensure their stability despite the gaps. Furthermore, MIWs effect on the fundamental period of the structures is examined, and a 20% reduction in the period for buildings with MIWs is recommended. Additionally, it is shown that the OOP stability of MIWs can be enhanced by adding small angle sections on the perimeter of MIWs.
  Keywords: masonry infill walls; MIWs; composite frame; out-of-plane stability; non-structural elements; infills.
  DOI: 10.1504/IJSTRUCTE.2024.10063562