Abstract
A cured-in-place pipe (CIPP) rehabilitation involves the installation of flexible polymeric liners within existing pipes. In contrast to pipe replacement, CIPP offers a cost-effective and environmentally sustainable solution for pipe rehabilitation. In conventional CIPP rehabilitation, lining pipes are glued to existing pipes. Even if the joint that connects existing pipes breaks owing to earthquake-induced ground deformation, the lining pipe can still resist tensile deformation. Therefore, the CIPP rehabilitation pipe is considered as effective in preventing joint pull-out. However, because the lining pipe must resist the tensile force on its own after the joint breaks, the lining pipe undergoes large strain. With this background, a novel low-friction CIPP rehabilitation approach was developed in this study. A friction-reducing layer was inserted between the existing pipes and lining pipes to reduce the strain transmitted from the existing pipe to the lining pipe. The objective of this study was to investigate the seismic performance of the low-friction rehabilitation pipe compared with the conventional glued-type rehabilitation pipe under earthquake-induced ground deformation using finite element analysis. To this end, a bending test and numerical analysis were first conducted, and the numerical model was validated by comparing the experimental results to the analysis results. Subsequently, the seismic performance was investigated using a 100-m-long rehabilitation pipe model under earthquake-induced ground deformation. The novel low-friction rehabilitation pipe drastically reduced the strain acting on the lining pipe, indicating that the lining pipe is less likely to be damaged by earthquakes.
Abstract
The novelty of this study lies in its systematic comparison and numerical analysis of sandwich panels with different core geometries (square, hexagonal, and circle-square) under imposed displacements and deformations using the finite element method. The strength and toughness of these sandwich structures are influenced by the interaction between the core and the face sheets, making their geometric configuration a critical factor. Using finite element analysis, three distinct core designs square, hexagonal (honeycomb), and a novel circle-square configuration are evaluated. The results reveal that the circle-square core exhibits superior load-bearing capacity and structural integrity compared to traditional square and honeycomb cores. This improvement is attributed to its optimized stress distribution and enhanced energy absorption, which mitigate localized failure mechanisms. This study provides a comprehensive assessment of the influence of core geometry and fiber orientation on the structural performance of sandwich composites. The key contribution is the identification of the circle-square core as an optimized design, demonstrating superior strength compared to square and hexagonal cores. The results showed that the circlesquare core exhibits a 25% higher resistance compared to the square panel and 17.6% higher than the hexagonal panel.
Key Words
core; displacement; fiber orientation; finite element method; honeycomb; laminated plates and sandwich structure
Address
Habib Achache: University of Oran 2 Mohamed Ben Ahmed, B.P 1015 El M'naouer Oran 31000, Algeria; Laboratory of Physical Mechanics of Materials Sidi Bel Abbes, Algeria
Djaafar Ait Kaci: Laboratory of Physical Mechanics of Materials Sidi Bel Abbes, Algeria; Department of Mechanical Engineering, University of Djillali Liabes Sidi Bel Abbes, 22000, Algeria
Rachid Zahi: Relizane University, Cité Bourmadia, BP 48000, Relizane, Algeria
Rachid Boughedaoui: Department of Materials Engineering, University Yahia Fares, Medea, Algeria
Abstract
Stainless steel (SS) rebars have gained substantial traction in the construction industry due to their superior corrosion resistance. Among SS rebars, such as austenitic SS and duplex SS, ferritic SS, which has lower chromium and nickel content, presents a cost-effective alternative. This study delves into the stress-strain models applicable to ferritic SS (grade 410L) ribbed reinforcing bars, analyzing their mechanical properties and ductility parameters in comparison to conventional carbon steel (Fe 500SD) rebars. Tensile tests were conducted on various diameters of ferritic SS (8 mm, 10 mm, 12 mm, and 16 mm) alongside carbon steel (CS) rebars, facilitating a comparative analysis of their mechanical properties and ductility. The results revealed
higher yield stress and ultimate strength in ferritic SS rebars, characterized by significant strain hardening but lower ductility parameter values compared to CS. Furthermore, the study assessed the applicability of existing stress-strain models—specifically, the Rasmussen and I. Arrayago models—in predicting the behaviour of ferritic SS rebars. While both models reasonably estimated the first-stage strain hardening parameter (n), they underpredicted the second-stage strain hardening parameter (m) based on the obtained test results.
Key Words
carbon steel; ductility; ferritic; rebar; stainless steel; tensile test
Address
Ankit K. Jaiswal and Sangeeta S. Gadve: Department of Applied Mechanics, Visvesvaraya National Institute of Technology, Nagpur, 440010, India
Abstract
The progress of theoretical research presents several difficulties, especially concerning the modeling of structures, unlike experimental research into the mechanical behavior of intricate systems. The objective of this study is to examine the free vibration characteristics of a novel composite structure known as functionally graded (FG) graphene-reinforced composite (GRC) coated shells. The material graduation is described by a complex power law function using a spatial variation of material properties, and the investigation focuses on coated FG shells with Hardcore and Softcore. Five patterns of GPLs distribution are considered in the study. These include a tridirectionally material distribution pattern (FG-A GRC), two bidirectional material distribution patterns (FG-B GRC and FG-C GRC), unidirectional transverse material distribution (FG-D GRC), and unidirectional axial material distribution (FG-E GRC). The governing equations are derived using the Principle of Hamilton and solved via the Galerkin technique, accounting for different boundary conditions. The paper details the impact of various factors, including hardcore and softcore distributions, gradation indexes, nonlocal and length-scale parameters, and boundary conditions on the frequencies of FG GRC-coated shells.
Address
Emad Esmat Ghandourah: Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia
Ahmed Amine Daikh: Artificial Intelligence Laboratory for Mechanical and Civil Structures, and Soil, University Centre of Naama, P.O. Box 66, Naama 45000, Algeria; Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, B.P. 305, R.P. 29000, Mascara, Algérie
Khatir Samir: Faculty of Civil Engineering, Ho Chi Minh City Open University, Ho Chi Minh City, Vietnam
Abdulsalam Alhawsawi: Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia
Essam Mohammed Banoqitah: Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia
Mohamed A. Eltaher: Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia; Mechanical Design & Production Department, Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt
Abstract
Tunnel-Form Buildings (TFBs) offer a rapid and cost-effective construction method for mass housing projects, particularly in low- to medium-rise structures. Despite their widespread use and favorable seismic performance, a lack of specific seismic design standards for TFBs persists. Moreover, the impact of diaphragm flexibility on their seismic behavior remains under-investigated, leading to uncertainties in structural design. The structural engineers often rely on general methods for reinforced concrete structures, which have proven inadequate. Given the substantial computation costs of TFBs, engineers are often tempted to consider the slabs as rigid diaphragms, whether rightly or wrongly. This study investigates the influence of diaphragm flexibility on the seismic response of two typical six-story TFB configurations employed in a large-scale housing project in Algeria. Utilizing validated finite element models, the structural behavior of these configurations under seismic loading was compared, taking into account both rigid and realistically modeled diaphragms. Linear and non-linear analyses are conducted to assess the impact of diaphragm flexibility on key performance parameters, including displacements, member forces, and energy dissipation mechanisms. The findings of this study contribute valuable insights for the seismic design and analysis of TFBs, providing a more accurate representation of their structural behavior and informing the development of improved design guidelines.
Address
Asma Hadjadj: Department of Interior Design Engineering, College of Engineering, University of Ha'il, Hail, Saudi Arabia
Abderrahmane Ouazir: Department of Civil Engineering, College of Engineering, University of Ha'il, Hail, Saudi Arabia
Mansour Ouazir: Department of Civil Engineering, El. Wanchrissi University, Tissemsilt, Algeria
Abstract
In recent years the integration of sustainable supplementary cementitious materials in construction has gained
substantial importance as part of efforts to improve carbon neutrality and reduce the ecological footprint of building industries. Sustainable development seeks the minimization of natural resource consumption by enhancing efficiency in their reuse and recycling processes. Granite waste powder was partially replaced for cement at percentages of 0%, 5%, 10%, 15%, 20%, and 25% by weight of cement. Polypropylene chopped fibers were added in the concrete mixture at volumetric percentages of 0%, 0.1%, 0.2%, 0.3%, and 0.4%. The fresh properties of concrete such as flowability, passing ability and resistance to segregation were performed to check the self-compacting characteristics of various mix. Mechanical properties such as compressive strength, tensile strength, and flexural strength have been analyzed in order to ascertain the structural behavior. Also, durability
properties such as water absorption, chloride penetration resistance and acid attack resistance have been studied so as to estimate the long-term performance of fibre reinforced self-compacting concrete. Experimental results obtained indicate that there is a synergy effect due to the inclusion of granite waste powder and polypropylene fibers on fresh and hardened characteristics. It improves the eco-efficiency of the concrete with respect to cement substitution by granite waste and maintains the workability and sufficient strength. By this approach, it is possible to reduce the construction cost besides supporting environmental sustainability by reducing waste production and conserving natural resources.
Address
R. Regupathi: Department of Civil Engineering, Government College of Engineering, Bodinayakanur, Theni, 625 582, Tamilnadu, India
S. Srividhya: Department of Civil Engineering, Builders Engineering College, Kangeyam, Tirupur, 638108, Tamilnadu, India
R. Prakash: Department of Civil Engineering, Alagappa Chettiar Government College of Engineering and Technology, Karaikudi, 630 003, Tamilnadu, India
M. Vinod Kumar: Department of Civil Engineering, Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and Technology, Chennai, 600 062, India
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