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Recent Advances and Development in Civil Engineering
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Recent Advances and Development in Civil Engineering

A topical collection in CivilEng (ISSN 2673-4109).

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Editors

Prof. Dr. Angelo Luongo

E-Mail Website
Collection Editor
Department of Civil, Construction-Architectural and Environmental Engineering, University of L’Aquila, Piazzale Ernesto Pontieri, Monteluco di Roio, 67100 L’Aquila, Italy
Interests: continuum and structural mechanics; linear and nonlinear dynamics; stability and bifurcation of dynamical systems; buckling and postbuckling of elastic structures; localization phenomena; aeroelasticity; perturbation methods; computational mechanics
Special Issues, Collections and Topics in MDPI journals
Dr. Simona Di Nino

E-Mail Website
Collection Editor
Department of Civil, Construction-Architectural and Environmental Engineering, University of L’Aquila, Piazzale Ernesto Pontieri, Monteluco di Roio, 67100 L’Aquila, Italy
Interests: continuum and structural mechanics; nonlinear dynamics; stability and bifurcation of dynamical systems; masonry structures; damage; aeroelasticity; perturbation methods; homogenization
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

This Topical Collection is devoted to academic researchers who want to propose studies in the principal fields of Civil Engineering.

Innovative contributions and feature papers are very welcome, especially in areas that include, without being limited to, the following topics:

Mathematical models for civil engineering: elasticity, plasticity, viscosity, damage, fractures, wave transmissions in solids and fluids, hydraulics, the dynamics of floating objects, coastal erosion modeling, urban modelling, transportation modeling.

Structural engineering: dynamics; stability; monitoring; control; identification and diagnosis; wind–structure, ground–structure, and fluid–structure interactions; the assessment, reliability, and optimization of structures; the strengthening and retrofitting of existing structures; timber engineering.

Earthquake engineering: soil–structure interactions, tectonics and seismology, seismic vibration control, protection systems, repair and strengthening, tsunamis.

Geotechnical engineering: foundations, retaining structures, soil dynamics, site characterization, slope stability.

Environmental engineering: climate changes, ecosystems, renewable energy, recycling.

Geo-spatial engineering: geodesy, digital photogrammetry, geographic information systems, remote sensing, satellite navigation.

Water resources engineering: hydropower project construction, water resource planning and management, water conservation and pollution, climate change and flood control.

Coastal and harbor engineering: tides and currents, dredging, sediment transport, climate change and sea levels, waterways, extreme weather events and hazards, shore protection and enhancement.

Transport engineering: road and railway engineering, air transportation, bridge and tunnel engineering, traffic control, transportation optimization, safety analysis, road maintenance.

Building physics and sustainable materials: new materials, improved materials, eco-materials.

Municipal or urban engineering: urban planning, supply networks, landscape design, design esthetics, public utilities, underground utilities, architecture maintenance and renewal, environmental assessments.

Engineering and economy: cost-effectiveness analysis, risk analysis, design economics, managing production operations, consumer adoption, policy analysis.

Construction engineering: construction management, performance-based design, construction material handling and selection, surface modification, construction pollution control.

Prof. Dr. Angelo Luongo
Dr. Simona Di Nino
Collection Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the collection website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. CivilEng is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • modeling
  • materials
  • structures
  • construction
  • control
  • monitoring
  • stability
  • earthquakes
  • water resources
  • coasts
  • transports
  • computational methods
  • experimental methods

Published Papers (9 papers)

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2024

21 pages, 8890 KiB  
Article
Structural Performance of a Hollow-Core Square Concrete Column Longitudinally Reinforced with GFRP Bars under Concentric Load
by AbdulMuttalib I. Said, Hussein A. Hilfi, Abbas A. Allawi and George Wardeh
CivilEng 2024, 5(4), 928-948; https://doi.org/10.3390/civileng5040047 (registering DOI) - 15 Oct 2024
Viewed by 254
Abstract
Concrete columns with hollow-core sections find widespread application owing to their excellent structural efficiency and efficient material utilization. However, corrosion poses a challenge in concrete buildings with steel reinforcement. This paper explores the possibility of using glass fiber-reinforced polymer (GFRP) reinforcement as a [...] Read more.
Concrete columns with hollow-core sections find widespread application owing to their excellent structural efficiency and efficient material utilization. However, corrosion poses a challenge in concrete buildings with steel reinforcement. This paper explores the possibility of using glass fiber-reinforced polymer (GFRP) reinforcement as a non-corrosive and economically viable substitute for steel reinforcement in short square hollow concrete columns. Twelve hollow short columns were meticulously prepared in the laboratory experiments and subjected to pure axial compressive loads until failure. All columns featured a hollow square section with exterior dimensions of (180 × 180) mm and 900 mm height. The columns were categorized into four separate groups with different variables: steel and GFRP longitudinal reinforcement ratio, hollow ratio, spacing between ties, and reinforcement type. The experimental findings point to the compressive participation of longitudinal GFRP bars, estimated to be approximately 35% of the tensile strength of GFRP bars. Notably, increasing GFRP longitudinal reinforcement significantly improved the ultimate load capability of hollow square GFRP column specimens. Specifically, elevating the ratio of GFRP reinforcement from 1.46% to 2.9%, 3.29%, 4.9%, and 5.85% resulted in axial load capacity improvements of 32.3%, 43.9%, 60.5%, and 71.7%, respectively. Specifically, the GFRP specimens showed a decrease in capacity of 13.1%, 9.2%, and 9.4%, respectively. Notably, the load contribution of steel reinforcement to GFRP reinforcement (with similar sectional areas) was from approximately three to four times the axial peak load, highlighting the greater load participation of steel reinforcement due to its higher elastic modulus. In addition, the numerical modeling and analysis conducted using ABAQUS/CAE 2019 software exhibited strong concordance with experimental findings concerning failure modes and capacity to carry axial loads. Full article
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Figure 1

Figure 1
<p>The reinforcement configurations for all columns.</p> Full article ">Figure 2
<p>Preparation of (<b>a</b>) column specimens’ molds and (<b>b</b>) reinforcement bars.</p> Full article ">Figure 3
<p>(<b>a</b>) Test configuration and equipment and (<b>b</b>) column specimens.</p> Full article ">Figure 4
<p>(<b>a</b>) Axial load vs. steel reinforcement ratio, (<b>b</b>) axial load vs. GFRP reinforcement ratio, (<b>c</b>) axial load vs. hollow ratio, (<b>d</b>) axial load vs. ties spacing.</p> Full article ">Figure 5
<p>The impact of varying reinforcement types on the axial load-bearing capacity.</p> Full article ">Figure 6
<p>Failure of the (<b>a</b>) steel reinforcing bars and (<b>b</b>) longitudinal GFRP bars.</p> Full article ">Figure 7
<p>Failure modes of all tested columns.</p> Full article ">Figure 8
<p>(<b>a</b>) Load–steel strain, (<b>b</b>) load–concrete strain (Group 1).</p> Full article ">Figure 9
<p>(<b>a</b>) Load–GFRP strain, (<b>b</b>) load–concrete strain (Group 2).</p> Full article ">Figure 10
<p>(<b>a</b>) Load–GFRP strain, (<b>b</b>) load–concrete strain (Group 3).</p> Full article ">Figure 11
<p>(<b>a</b>) Load–GFRP strain, (<b>b</b>) load–concrete strain (Group 4).</p> Full article ">Figure 12
<p>(<b>a</b>) Load–axial displacement curves, (<b>b</b>) load–lateral displacement curves (Group 1).</p> Full article ">Figure 13
<p>(<b>a</b>) Load–axial displacement curves, (<b>b</b>) Load–lateral displacement curves (Group 2).</p> Full article ">Figure 14
<p>(<b>a</b>) Load–axial displacement curves, (<b>b</b>) load–lateral displacement curves (Group 3).</p> Full article ">Figure 15
<p>(<b>a</b>) Load–axial displacement curves, (<b>b</b>) load–lateral displacement curves (Group 4).</p> Full article ">Figure 16
<p>Numerical and experimental failure pattern.</p> Full article ">
26 pages, 9795 KiB  
Article
Three-Dimensional Site Response Analysis of Clay Soil Considering the Effects of Soil Behavior and Type
by Rania Al-Ahmar, Mayada Al Ahmad Al Kousa, Amjad Al-Helwani and George Wardeh
CivilEng 2024, 5(4), 866-891; https://doi.org/10.3390/civileng5040045 - 8 Oct 2024
Viewed by 294
Abstract
To understand changes in bedrock motion at the ground surface, frequency effects, and spatial distribution within the soil, it is important to look at how a site responds to earthquakes. This is important for soil–structure interaction in structural and geotechnical earthquake engineering. This [...] Read more.
To understand changes in bedrock motion at the ground surface, frequency effects, and spatial distribution within the soil, it is important to look at how a site responds to earthquakes. This is important for soil–structure interaction in structural and geotechnical earthquake engineering. This study deals with the effect of classifying clays according to shear wave velocity (stiff/medium/soft) and nonlinearity in behavior (linear/nonlinear) on the analysis of the site response. A 3D soil model with a combination of free fields and quiet boundaries and advanced constitutive models for soil to obtain accurate results was used to conduct this study. A strong TABAS earthquake was used to excite the compliant base of the model after converting the velocity record of TABAS to an equivalent surface traction force using a horizontal force–time history proportional to the velocity–time history. This study reveals that the site response analysis is affected by the type of clay soil and the soil material behavior, with soft clay soil causing higher PGV and PGV values in the linear case and lower values in the nonlinear case due to soil yielding, which causes soil response attenuation. This results in extremely conservative and expensive building designs when linear soil behavior is adopted. On the other hand, the applied earthquake exhibits greater attenuation at longer frequencies and greater amplification at mid and short frequencies. However, at frequencies near the applied earthquake frequency, neither attenuation nor amplification occurs. Furthermore, nonlinear soil behavior is crucial for soil evaluation and foundation design due to higher octahedral shear strain and settlement values, especially in softer soils, resulting from extensive plastic deformation. Full article
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>The dimensions and mesh of the: (<b>a</b>) 3D perspective of the finite element model (the purple color between the interior soil and free fields and between adjacent free fields represents zero-length Lysmer-Kuhlemeyer dashpot elements, while purple lines within each free field represent the equal DOF multi-point mp constraints), (<b>b</b>) elevation of the soft soil model, (<b>c</b>) elevation of the medium soil model, and (<b>d</b>) elevation of the stiff soil model.</p> Full article ">Figure 2
<p>Schematic representation of the boundary conditions utilized in seismic analysis, including Lysmer–Kuhlemeyer dashpots for the compliant base and quiet boundaries, as well as free-field boundaries.</p> Full article ">Figure 3
<p>Lysmer–Kuhlemeyer dashpots incorporated into (<b>a</b>) the lateral boundaries “<math display="inline"><semantics> <mrow> <mi mathvariant="bold-italic">L</mi> <mi mathvariant="bold-italic">K</mi> <mn>1</mn> </mrow> </semantics></math>” (in addition to equal DOF for free-fields) and (<b>b</b>) the base of the model “<math display="inline"><semantics> <mrow> <mi mathvariant="bold-italic">L</mi> <mi mathvariant="bold-italic">K</mi> <mn>2</mn> </mrow> </semantics></math>”. The red color shows these Lysmer–Kuhlemeyer dashpots <math display="inline"><semantics> <mrow> <mi mathvariant="bold-italic">L</mi> <mi mathvariant="bold-italic">K</mi> <mn>1</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="bold-italic">L</mi> <mi mathvariant="bold-italic">K</mi> <mn>2</mn> </mrow> </semantics></math>, in addition to the equal DOF constraints within free fields.</p> Full article ">Figure 4
<p>TABAS earthquake characteristics and components: (<b>a</b>) acceleration–time history, (<b>b</b>) velocity–time history, and (<b>c</b>) velocity’s Fourier spectrum.</p> Full article ">Figure 4 Cont.
<p>TABAS earthquake characteristics and components: (<b>a</b>) acceleration–time history, (<b>b</b>) velocity–time history, and (<b>c</b>) velocity’s Fourier spectrum.</p> Full article ">Figure 5
<p>The hyperbolic backbone curve of the nonlinear (shear–strain) of clay soil and a piecewise linear representation of the plasticity with multiple surfaces (after [<a href="#B45-civileng-05-00045" class="html-bibr">45</a>,<a href="#B46-civileng-05-00045" class="html-bibr">46</a>,<a href="#B47-civileng-05-00045" class="html-bibr">47</a>]): (<b>a</b>) octahedral shear stress-strain; (<b>b</b>) Von Mises-type multiple yield surfaces.</p> Full article ">Figure 6
<p>Illustration of the selected point used to record output parameters at the top of the soil, by zooming in on the soil model.</p> Full article ">Figure 7
<p>Variation of Vx velocity–time histories in the upper part of (<b>a</b>) linear soil and (<b>b</b>) nonlinear clay soil. (Recorded at the marker point).</p> Full article ">Figure 7 Cont.
<p>Variation of Vx velocity–time histories in the upper part of (<b>a</b>) linear soil and (<b>b</b>) nonlinear clay soil. (Recorded at the marker point).</p> Full article ">Figure 8
<p>Variation of Settlement U<sub>z</sub> at the top of (<b>a</b>) linear; (<b>b</b>) all clay soil. (Recorded at mark point).</p> Full article ">Figure 8 Cont.
<p>Variation of Settlement U<sub>z</sub> at the top of (<b>a</b>) linear; (<b>b</b>) all clay soil. (Recorded at mark point).</p> Full article ">Figure 9
<p>Fourier spectrum for velocity at the top of the (<b>a</b>) linear; (<b>b</b>) nonlinear clay soil. (Recorded at mark point).</p> Full article ">Figure 10
<p>Change of Uz settlements for half of the internal soil profile section in all studied clay soils (Stiff, Medium, Soft) with: (<b>a</b>) linear elastic soil material; (<b>b</b>) nonlinear (PIMY) soil material, at the end of the earthquake t = 21 s deformation scale = 15.</p> Full article ">Figure 10 Cont.
<p>Change of Uz settlements for half of the internal soil profile section in all studied clay soils (Stiff, Medium, Soft) with: (<b>a</b>) linear elastic soil material; (<b>b</b>) nonlinear (PIMY) soil material, at the end of the earthquake t = 21 s deformation scale = 15.</p> Full article ">Figure 11
<p>Change of octahedral shear strain for half of the internal soil section in all studied soils (Stiff, Medium, Soft) with (<b>a</b>) linear elastic soil material; (<b>b</b>) nonlinear (PIMY) soil material, at the end of the earthquake t = 21 s deformation scale = 1.</p> Full article ">Figure 11 Cont.
<p>Change of octahedral shear strain for half of the internal soil section in all studied soils (Stiff, Medium, Soft) with (<b>a</b>) linear elastic soil material; (<b>b</b>) nonlinear (PIMY) soil material, at the end of the earthquake t = 21 s deformation scale = 1.</p> Full article ">Figure A1
<p>Partition mesh for the studied model (the case of stiff clay): (<b>a</b>) the number of nodes and elements in each partition; (<b>b</b>) The shape and distribution of the partitions in the model.</p> Full article ">Figure A2
<p>Variation of the acceleration–time histories A<sub>X</sub> at the top of (<b>a</b>) linear and (<b>b</b>) nonlinear clay soil. (Recorded at mark point).</p> Full article ">Figure A3
<p>Variation of the displacement–time histories U<sub>X</sub> at the top of (<b>a</b>) linear and (<b>b</b>) nonlinear clay soil. (Recorded at mark point).</p> Full article ">Figure A3 Cont.
<p>Variation of the displacement–time histories U<sub>X</sub> at the top of (<b>a</b>) linear and (<b>b</b>) nonlinear clay soil. (Recorded at mark point).</p> Full article ">Figure A4
<p>Fourier spectrum for acceleration at the top of the (<b>a</b>) linear and (<b>b</b>) nonlinear clay soil. (Recorded at mark point).</p> Full article ">Figure A5
<p>Change of octahedral shear stress for half of the internal soil section in all studied soils with (<b>a</b>) linear elastic soil material; (<b>b</b>) nonlinear (PIMY) soil material, at t = 6.7 s (where the maximum TABAS acceleration is) deformation scale = 1.</p> Full article ">
25 pages, 10627 KiB  
Article
A Study on Differences in Educational Method to Periodic Inspection Work of Nuclear Power Plants
by Yuichi Yashiro, Gang Wang, Fumio Hatori and Nobuyoshi Yabuki
CivilEng 2024, 5(3), 760-784; https://doi.org/10.3390/civileng5030040 - 9 Sep 2024
Viewed by 525
Abstract
Construction work and regular inspection work at nuclear power plants involve many special tasks, unlike general on-site work. In addition, the opportunity to transfer knowledge from skilled workers to unskilled workers is limited due to the inability to easily enter the plant and [...] Read more.
Construction work and regular inspection work at nuclear power plants involve many special tasks, unlike general on-site work. In addition, the opportunity to transfer knowledge from skilled workers to unskilled workers is limited due to the inability to easily enter the plant and various security and radiation exposure issues. Therefore, in this study, we considered the application of virtual reality (VR) as a method to increase opportunities to learn anytime and anywhere and to transfer knowledge more effectively. In addition, as an interactive learning method to improve comprehension, we devised a system that uses hand tracking and eye tracking to allow participants to experience movements and postures that are closer to the real work in a virtual space. For hand-based work, three actions, “pinch”, “grab”, and “hold”, were reproduced depending on the sizes of the parts and tools, and visual confirmation work was reproduced by the movement of the gaze point of the eyes, faithfully reproducing the special actions of the inspection work. We confirmed that a hybrid learning process that appropriately combines the developed active learning method, using experiential VR, with conventional passive learning methods, using paper and video, can improve the comprehension and retention of special work at nuclear power plants. Full article
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Figure 1

Figure 1
<p>DIKW model (drawn by the author based on [<a href="#B4-civileng-05-00040" class="html-bibr">4</a>]).</p> Full article ">Figure 2
<p>SECI model (drawn by the author based on [<a href="#B5-civileng-05-00040" class="html-bibr">5</a>]).</p> Full article ">Figure 3
<p>Experiment flowchart.</p> Full article ">Figure 4
<p>Learning pyramid (drawn by the author based on [<a href="#B11-civileng-05-00040" class="html-bibr">11</a>]).</p> Full article ">Figure 5
<p>Overview of the developed experiential VR system.</p> Full article ">Figure 6
<p>Experience-based VR system and screen example.</p> Full article ">Figure 7
<p>Predefined tool for tool grip point, orientation, and angle.</p> Full article ">Figure 8
<p>Screenshot of the content creation support tool.</p> Full article ">Figure 9
<p>Examples of the created content screen. (<b>a</b>) Visual confirmation of nameplate, (<b>b</b>) Nut loosening work, (<b>c</b>) O-ring removal work, (<b>d</b>) Piping removal work.</p> Full article ">Figure 10
<p>Subjects at the time of the experience. (<b>a</b>) Subject during O-ring removal work, (<b>b</b>) Subject during piping removal work.</p> Full article ">Figure 11
<p>Excerpts from the test.</p> Full article ">Figure 12
<p>Hybrid learning experiment flow.</p> Full article ">Figure 13
<p>Status during the measurement of the degree of work implementation.</p> Full article ">Figure 14
<p>Graphs of comprehension test measurement results with learning materials.</p> Full article ">Figure 15
<p>Graph of hybrid learning comprehension improvement measurement results.</p> Full article ">Figure 16
<p>Graph of the work retention measurement experimental results.</p> Full article ">Figure 17
<p>Graph of the results of each question in the ARCS questionnaire.</p> Full article ">Figure A1
<p>All test questions.</p> Full article ">
24 pages, 563 KiB  
Article
Enhancing Onshore Wind Tower Foundations: A Comprehensive Automated Design Approach
by Emmanouil Vougioukas, Athanasios Stamos, Charikleia Pappa and Nikos D. Lagaros
CivilEng 2024, 5(3), 736-759; https://doi.org/10.3390/civileng5030039 - 3 Sep 2024
Viewed by 1091
Abstract
The realm of green energy is in constant flux, drawing considerable attention from stakeholders dedicated to minimizing environmental impact, reducing costs, and developing structures that align with stringent standards. This study introduces an innovative approach aimed at improving onshore wind tower foundation systems, [...] Read more.
The realm of green energy is in constant flux, drawing considerable attention from stakeholders dedicated to minimizing environmental impact, reducing costs, and developing structures that align with stringent standards. This study introduces an innovative approach aimed at improving onshore wind tower foundation systems, emphasizing both engineering and financial feasibility. The approach involves a comprehensive analysis of design load cases, particularly emphasizing resistance against overturn, while ensuring compliance with Eurocode guidelines. The foundation system is conceptualized as a beam slab with voids filled by soil material. High reduction in concrete quantity is achieved by reaching 30%, while the steel reduction reaches 90%. It is worth mentioning that the total cost is reduced by up to 70%. Furthermore, as a future trend, this study aims to integrate the new foundation system with steel 3D printing technology in the manufacturing process of the wind tower’s structural elements. This integration is expected to enhance the precision and customization of the superstructure-foundation system, thereby improving overall performance and efficiency. The optimized design not only significantly reduces construction costs but also streamlines installation, saving time. Simultaneously, this study enhances the structural behavior of the wind tower foundation by focusing on elements crucial to its efficiency. Full article
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Figure 1
<p>Forces applied on the wind turbine foundation.</p> Full article ">Figure 2
<p>Flowchart of the automated design process.</p> Full article ">Figure 3
<p>Lay out of the proposed foundation system.</p> Full article ">Figure 4
<p>Section A of the proposed foundation.</p> Full article ">
19 pages, 5988 KiB  
Article
Geotechnical and Geophysical Assessment of the Soil Layers of the Missan Combined-Cycle Power Plant Project
by Ruba H. Sa’ur, Duaa Al-Jeznawi, Saif Alzabeebee, Luís Filipe Almeida Bernardo and Suraparb Keawsawasvong
CivilEng 2024, 5(3), 717-735; https://doi.org/10.3390/civileng5030038 - 29 Aug 2024
Viewed by 832
Abstract
This study investigated the geotechnical and geophysical properties of the soil layers at the Missan combined-cycle power plant in Iraq. The data from 69 boreholes, including physical and chemical soil properties, were analyzed. The soil is primarily classified as silty clay with moderate [...] Read more.
This study investigated the geotechnical and geophysical properties of the soil layers at the Missan combined-cycle power plant in Iraq. The data from 69 boreholes, including physical and chemical soil properties, were analyzed. The soil is primarily classified as silty clay with moderate to high plasticity, with some sandy layers. Since the Missan governorate is located in a seismically active region represented by the Iraq–Iran border, a study on the seismic properties of the site is also performed. Seismic downhole tests were conducted to determine wave velocities and dynamic moduli. The site was classified as soft clay soil according to FEMA and Eurocode 8 standards. Correlations for the physical and dynamic soil properties were evaluated. The correlations were executed via regression statistical analysis via Microsoft Excel software (2013). The results of the correlation equations and the coefficient of correlation R2 show that the physical correlations were considered medium to good correlations, whereas the dynamic soil correlations were perfectly correlated such that the R2 values were close to 1. This paper provides comprehensive data and soil property correlations, which can be valuable for future construction projects in the Missan area and similar geological formations. Full article
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Figure 1

Figure 1
<p>Iraq map representing the study area.</p> Full article ">Figure 2
<p>Borehole positions within the study area.</p> Full article ">Figure 3
<p>Subsurface soil layers through boreholes #1, #7, #13, and #20.</p> Full article ">Figure 4
<p>Change in the SPT value with soil depth.</p> Full article ">Figure 5
<p>(<b>a</b>) Changes in the liquid limit, (<b>b</b>) plastic limit, and (<b>c</b>) plasticity index with soil depth.</p> Full article ">Figure 6
<p>(<b>a</b>) Changes in the compression index, (<b>b</b>) compression index, and (<b>c</b>) initial void ratio with soil depth.</p> Full article ">Figure 7
<p>Single-borehole seismic method (downhole test).</p> Full article ">Figure 8
<p>Shear and compressional wave velocities (V<sub>s</sub> and V<sub>p</sub>) with soil depth.</p> Full article ">Figure 9
<p>Bulk density vs. shear and compressional wave velocities: (<b>a</b>) V<sub>p</sub> and (<b>b</b>) V<sub>s</sub>.</p> Full article ">Figure 10
<p>The dynamic moduli with soil depth: (<b>a</b>) G<sub>d</sub>, (<b>b</b>) E<sub>d</sub>, and (<b>c</b>) K<sub>d</sub>.</p> Full article ">Figure 11
<p>Correlation of SPT (N value) vs. cohesion C (kPa).</p> Full article ">Figure 12
<p>Correlation of the PI % vs. cohesion C (kPa).</p> Full article ">Figure 13
<p>Correlation of void ratio e<sub>0</sub> vs. compression index C<sub>c</sub>.</p> Full article ">Figure 14
<p>The correlation of the density, γ, with the dynamic modulus of elasticity E<sub>d</sub>.</p> Full article ">Figure 15
<p>The correlation of density, γ, with compression wave velocity, V<sub>p</sub>.</p> Full article ">Figure 16
<p>Correlation of density, γ, vs. shear wave velocity, vs.</p> Full article ">
27 pages, 20408 KiB  
Article
Experimental and FE Investigations of Backfill Cover on Large-Diameter GRP Pipes
by AbdulMuttalib I. Said, Yahya Jabbar Hussien, Mohammed Hazim Mohammed, Abbas A. Allawi, Teghreed H. Ibrahim, Ayman El-Zohairy and Ahmed M. Abdelbaset
CivilEng 2024, 5(3), 646-672; https://doi.org/10.3390/civileng5030035 - 7 Aug 2024
Viewed by 937
Abstract
This paper presents experimental investigations on buried Glass Reinforced Plastic (GRP) pipes with a diameter of 1400 mm. The tested pipes were buried in dense, gravelly sand and subjected to traffic loads to study the effects of backfill cover on pipe deflection. The [...] Read more.
This paper presents experimental investigations on buried Glass Reinforced Plastic (GRP) pipes with a diameter of 1400 mm. The tested pipes were buried in dense, gravelly sand and subjected to traffic loads to study the effects of backfill cover on pipe deflection. The experimental program included tests on three GRP pipes with backfill covers of 100 cm, 75 cm, and 50 cm. The maximum traffic loads applied to the pipe–soil system corresponded to Iraqi Truck Type 3 (AASHTO H type). Vertical deflections of the pipes were monitored during the application of these loads. The experimental results showed that, as the backfill cover increased, the maximum vertical deflection of the pipe decreased. Deflection reductions were 38.0% and 33.3% when the backfill increased from 50 cm to 100 cm and from 50 cm to 75 cm, respectively. A 500 mm compacted backfill cover was found to be sufficient to resist traffic loads, with the vertical deflection percentage remaining below the allowable limit. Additionally, the behavior of the GRP pipes under different traffic load configurations was analyzed using finite element (FE) analysis with Plaxis 3D. The model was validated using field data. The study investigated numerous variables impacting the behavior of embedded pipes, including pipe material, pipe thickness, backfill properties, backfill depth, and the properties of the soil beneath the GRP pipe. The deflections of the steel pipe were lower than those of the GRP pipe when using different thicknesses. Full article
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Figure 1

Figure 1
<p>Grain size distribution for granular material.</p> Full article ">Figure 2
<p>The pin location 1 m from the far pipe end.</p> Full article ">Figure 3
<p>The representative compaction curve (water content versus dry unit weight).</p> Full article ">Figure 4
<p>Legal axle and gross weight permitted on motor vehicles in regular operation in Iraq.</p> Full article ">Figure 5
<p>Installations and backfilling method.</p> Full article ">Figure 6
<p>Test variables.</p> Full article ">Figure 7
<p>Displacement directions.</p> Full article ">Figure 8
<p>Deflection results of 1400 mm diameter pipes in different tests.</p> Full article ">Figure 8 Cont.
<p>Deflection results of 1400 mm diameter pipes in different tests.</p> Full article ">Figure 9
<p>Vertical deflections percentage results of 1400 mm diameter pipes in different tests.</p> Full article ">Figure 10
<p>Finite element model using Plaxis 3D.</p> Full article ">Figure 11
<p>Cross-section of the studied model.</p> Full article ">Figure 12
<p>Comparison between Mohr–Coulomb, hardening soil, and modified cam clay models [<a href="#B3-civileng-05-00035" class="html-bibr">3</a>].</p> Full article ">Figure 13
<p>Comparisons between the FE and experimental load-deflection relationships.</p> Full article ">Figure 13 Cont.
<p>Comparisons between the FE and experimental load-deflection relationships.</p> Full article ">Figure 14
<p>Deflections of the analyzed pipes under load No. 2 (case of 100 cm backfill).</p> Full article ">Figure 15
<p>Deflection of the analyzed pipes under load No. 1.</p> Full article ">Figure 16
<p>Deflection of the analyzed pipes under load No. 5.</p> Full article ">Figure 17
<p>Layout of the truck tires.</p> Full article ">Figure 18
<p>Pipe deflection with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and backfill depth (H = 0.50 m).</p> Full article ">Figure 19
<p>Pipe deflection with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and backfill depth (H = 1.00 m).</p> Full article ">Figure 20
<p>Pipe deflection with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and backfill depth (H = 1.50 m).</p> Full article ">Figure 21
<p>Pipe deflection with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and backfill depth (H = 2.00 m).</p> Full article ">Figure 22
<p>Comparisons of the pipe deflection with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and backfill depth (H = 1.00 m).</p> Full article ">Figure 23
<p>Pipe deflection with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 0.50 m).</p> Full article ">Figure 24
<p>Pipe deflection with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 1.00 m).</p> Full article ">Figure 25
<p>Pipe deflection with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 1.50 m).</p> Full article ">Figure 26
<p>Pipe deflection with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 2.00 m).</p> Full article ">Figure 27
<p>Comparisons of pipe deflection with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 1.00 m).</p> Full article ">Figure 28
<p>Pipe deflection with different pipe diameters (d) and constant backfill depth (H = 1.00 m), pipe thickness (t = 15 mm), and bedding depth (D = 1.00 m).</p> Full article ">Figure 29
<p>Comparisons of the pipe deflection between 1.00 m and 2.50 m diameter pipes.</p> Full article ">Figure 30
<p>GRP pipe deflection with different pipe thicknesses (t) and constant backfill depth (H = 1.00 m), pipe diameter (d = 1.5 m), and bedding depth (D = 1.00 m).</p> Full article ">Figure 31
<p>Steel pipe deflection with different pipe thicknesses (t) and constant backfill depth (H = 1.00 m), pipe diameter (d = 1.5 m), and bedding depth (D = 1.00 m).</p> Full article ">Figure 32
<p>Comparisons between steel and GRP pipes with pipe thickness (t = 30 mm), backfill depth (H = 1.00 m), pipe diameter (d = 1.5 m), and bedding depth (D = 1.00 m).</p> Full article ">Figure 33
<p>Normal force in the GRP pipe with different backfill depths (H) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm) and bedding depth (D = 1.00 m).</p> Full article ">Figure 34
<p>Normal force in the GRP pipe with different bedding depths (D) and constant pipe diameter (d = 1.00 m), pipe thickness (t = 15 mm) and backfill depth (H = 1.00 m).</p> Full article ">Figure 35
<p>Axial normal force in the GRP pipe with pipe thickness (t = 15 mm), backfill depth (H = 1.50 m), pipe diameter (d = 1.00 m), and bedding depth (D = 1.00 m).</p> Full article ">
15 pages, 3939 KiB  
Article
Blast Wave Simulator for Laminated Glass Panels Experimental Evaluation
by Mahmoud T. Nawar, Ayman El-Zohairy, Alaa El-Sisi, Hani Salim and Abdelhakim A. Aldoshan
CivilEng 2024, 5(3), 576-590; https://doi.org/10.3390/civileng5030031 - 15 Jul 2024
Viewed by 783
Abstract
The study of blast loads on structures is important due to the potential of significant consequences in various scenarios. From terrorist attacks to industrial accidents, comprehending how structures respond to blast waves is critical for ensuring public safety and designing resilient structures. Studying [...] Read more.
The study of blast loads on structures is important due to the potential of significant consequences in various scenarios. From terrorist attacks to industrial accidents, comprehending how structures respond to blast waves is critical for ensuring public safety and designing resilient structures. Studying these effects typically involves two main methods: free-field tests with live explosives and shock tube tests. Although shock tube testing offers certain advantages, both approaches are costly and demand significant space. This research aims to develop a cost-effective and straightforward technique for generating stress waves that closely replicate the progressive and spatial characteristics of free-field or shock tube blast waves. This method was designed to evaluate the dynamic response of laminated glass panels. The stress wave was generated by impacting a piston on the fluid inside a tube, which was connected to a fluid chamber. This setup produced impulsive loads that were distributed across a laminated glass test panel. Moreover, it was used to simulate the shock near filed explosions for a certain part of a structure. High-speed cameras were utilized to analyze the initial velocity of flying glass fragments. The apparatus successfully produced various blast waves and impulsive profiles for different drop weight heights. The initial velocities of randomly selected flying shards ranged from 3 m/s to 4 m/s. Full article
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<p>Drop weight testing setup. (<b>a</b>) Drop weight apparatus; (<b>b</b>) Different components of stress wave generator PCB Piezotronics Pressure sensor; (<b>c</b>) Piston and tube pressure testing; (<b>d</b>) Chamber pressure testing with steel plate; (<b>e</b>) Chamber pressure testing with aluminum plate.</p> Full article ">Figure 2
<p>Testing of LG panels by using the dynamic stress wave generator before and after failure. (<b>a</b>) Sample #1 before the test; (<b>b</b>) Sample #1 attached to the wave generator; (<b>c</b>) Failed sample #1; (<b>d</b>) Failed sample 2; (<b>e</b>) Failed sample 3; (<b>f</b>) Flaying glass shards; (<b>g</b>) Selected frames from the high-speed video (The dotted line is a reference line to show the deflection at the certain selected times).</p> Full article ">Figure 3
<p>Pressure-time history and impulse inside the piston.</p> Full article ">Figure 4
<p>Steel chamber pressure-time history and impulse.</p> Full article ">Figure 5
<p>Chamber and piston results comparison for using W = 4.35 kg at three different heights of H1 = 304.8 mm, H2 = 609.6 mm, and H3 = 914.4 mm.</p> Full article ">Figure 6
<p>Pressure-time history and displacement-time history of aluminum plate 3.17 mm sample using 7.94 kg weight at 1524 mm height.</p> Full article ">Figure 7
<p>Pressure-time history and displacement-time history of LG samples.</p> Full article ">Figure 8
<p>Test setup using a plain mirror to record the glass cracking process.</p> Full article ">Figure 9
<p>Selected frames from high-speed video of testing of an LG Panel (cracking history).</p> Full article ">Figure 10
<p>Comparison between pressure-time and impulse history for 3.17 mm aluminum plate and LG sample # 3 (no breakage pressure) using 7.94 kg weight at 1524 mm height.</p> Full article ">Figure 11
<p>Pressure-time history and displacement-time history of LG Sample [<a href="#B22-civileng-05-00031" class="html-bibr">22</a>].</p> Full article ">
17 pages, 3530 KiB  
Review
Application of Long-Period Fiber Grating Sensors in Structural Health Monitoring: A Review
by Ying Zhuo, Pengfei Ma, Pu Jiao and Xinzhe Yuan
CivilEng 2024, 5(3), 559-575; https://doi.org/10.3390/civileng5030030 - 13 Jul 2024
Viewed by 1097
Abstract
Structural health monitoring (SHM) is crucial for preventing and detecting corrosion, leaks, and other risks in reinforced concrete (RC) structures, ensuring environmental safety and structural integrity. Optical fiber sensors (OFS), particularly long-period fiber gratings (LPFG), have emerged as a promising method for SHM. [...] Read more.
Structural health monitoring (SHM) is crucial for preventing and detecting corrosion, leaks, and other risks in reinforced concrete (RC) structures, ensuring environmental safety and structural integrity. Optical fiber sensors (OFS), particularly long-period fiber gratings (LPFG), have emerged as a promising method for SHM. Various LPFG sensors have been widely used in SHM due to their high sensitivity, durability, immunity to electromagnetic interference (EMI) and compact size. This review explores recent advancements in LPFG sensors and offers insights into their potential applications in SHM. Full article
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<p>Sensing principle of an LPFG sensor.</p> Full article ">Figure 2
<p>Schematic setup for LPFG fabrication by a CO<sub>2</sub> laser.</p> Full article ">Figure 3
<p>Schematic setup for LPFG fabrication by the EAD method.</p> Full article ">Figure 4
<p>Schematic setup for the simultaneous measurement of strain and temperature.</p> Full article ">Figure 5
<p>Schematic setup for the LPFG-based RH sensors [<a href="#B44-civileng-05-00030" class="html-bibr">44</a>].</p> Full article ">Figure 6
<p>Structure of the PI-coated LPFG RH sensor with a silver mirror at the end.</p> Full article ">Figure 7
<p>Schematic diagram of the SILPG Michelson Interferometer.</p> Full article ">Figure 8
<p>Experimental setup of the corrosion sensors proposed by H. Liu [<a href="#B75-civileng-05-00030" class="html-bibr">75</a>].</p> Full article ">Figure 9
<p>Schematic diagram of an LPFG corrosion sensor coated with nano iron/silica particles [<a href="#B76-civileng-05-00030" class="html-bibr">76</a>].</p> Full article ">Figure 10
<p>A general design of Fe-C-coated LPFG sensors.</p> Full article ">
12 pages, 3347 KiB  
Article
Impact of the Fly Ash/Alkaline Activator Ratio on the Microstructure and Dielectric Properties of Fly Ash KOH-Based Geopolymer
by Meenakshi Yadav, Neha Saini, Lalit Kumar, Vidya Nand Singh, Karthikeyan Jagannathan and V. Ezhilselvi
CivilEng 2024, 5(2), 537-548; https://doi.org/10.3390/civileng5020028 - 19 Jun 2024
Viewed by 1156
Abstract
Geopolymer materials, alternatives to cement that are synthesized using industrial byproducts, have emerged as some of the leading champion materials due to their environmentally friendly attributes. They can significantly reduce pollution by utilizing a plethora of waste products and conserving natural resources that [...] Read more.
Geopolymer materials, alternatives to cement that are synthesized using industrial byproducts, have emerged as some of the leading champion materials due to their environmentally friendly attributes. They can significantly reduce pollution by utilizing a plethora of waste products and conserving natural resources that would otherwise be used in the production of conventional cement. Much work is being carried out to study geopolymers’ characteristics under different conditions. Here, a geopolymer derived from fly ash (FA) was synthesized using a combination of sodium silicate and potassium hydroxide (KOH) (2.5:1 ratio) as an alkali activator (AA) liquid. The FA/AA ratios were optimized, resulting in distinct geopolymer samples with ratios of 1.00, 1.25, 1.50, and 1.75. By adjusting the contribution of alkaline liquid, we investigated the impacts of subtle changes in the FA/AA ratio on the morphology and microstructure using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques. The FESEM analysis illustrated a mixed matrix and morphology, with the sample with a ratio of 1.00 displaying consistently fused and homogenous morphology. The XRD results revealed the prevalent amorphous nature of geopolymer with a few crystalline phases of quartz, sodalite, hematite, and mullite. An electrical study confirmed the insulating nature of the geopolymer samples. Insulating geopolymers can provide energy-efficient buildings and resistance to fire, hurricanes, and tornadoes. Additionally, using KOH as a part of the alkali activator introduced a less-explored aspect compared to conventional sodium hydroxide-based activators, highlighting the novelty in the synthesis process. Full article
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<p>Raw material sources, activators, and diverse applications of geopolymers.</p> Full article ">Figure 2
<p>Surface morphology of fly ash.</p> Full article ">Figure 3
<p>SEM images of fly ash KOH-based geopolymers prepared with different ratios of FA/AA: (<b>a</b>) 1.00 (G1), (<b>b</b>) 1.25 (G2), (<b>c</b>) 1.50 (G3), and (<b>d</b>) 1.75 (G4).</p> Full article ">Figure 4
<p>XRD spectra of fly ash.</p> Full article ">Figure 5
<p>XRD spectra of the fly ash KOH-based geopolymers prepared with different ratios of FA/AA: (a) 1.00 (G1), (b) 1.25 (G2), (c) 1.50 (G3), and (d) 1.75 (G4).</p> Full article ">Figure 6
<p>Conductivity versus frequency plot of geopolymers prepared with different ratios of FA/AA: (a) 1.00 (G1), (b) 1.25 (G2), (c) 1.50 (G3), and (d) 1.75 (G4).</p> Full article ">Figure 7
<p>Plot of the permittivity/dielectric constant versus frequency of geopolymers prepared with different ratios of FA/AA: (a) 1.00 (G1), (b) 1.25 (G2), (c) 1.50 (G3), and (d) 1.75 (G4).</p> Full article ">Figure 8
<p>Plot of the D factor versus frequency of fly ash KOH-based geopolymers prepared with different ratios of FA/AA: (a) 1.00 (G1), (b) 1.25 (G2), (c) 1.50 (G3), and (d) 1.75 (G4).</p> Full article ">
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