rss_2.0Selected Scientific Papers - Journal of Civil Engineering FeedSciendo RSS Feed for Selected Scientific Papers - Journal of Civil Engineering Scientific Papers - Journal of Civil Engineering Feed Optimization of Retaining Wall Using Genetic Algorithm<abstract> <title style='display:none'>Abstract</title> <p>This paper examines the importance of geotechnical optimization techniques for soil engineering applications, with a particular emphasis on evaluating geotechnical structures. Due to its prevalence in civil engineering, the complex interplay of geotechnical, structural, and financial considerations necessitates a trial and error approach. The study focuses on design elements, geometric dimensions, and volume considerations in order to highlight the economic viability of reinforced concrete retaining walls. Three code files are created using MATLAB to analyze their impact on active and passive thrusts and, as a result, the structure’s volume. The slope angle, backfill overload, and friction angle are varied. The results demonstrate the effectiveness of using evolutionary algorithms to precisely optimize a single goal and demonstrate that this approach can enhance the design of retaining walls in reinforced concrete. This method demonstrates the ability to improve design procedures in this crucial area, which makes it an invaluable resource for structural engineering researchers and civil engineers.</p> </abstract>ARTICLEtrue Waste Sheets Effects on Reclaimed Asphalt Pavement Performances<abstract> <title style='display:none'>Abstract</title> <p>This paper aims to examine physical and mechanical performances of a Reclaimed asphalt pavement (RAP) material reinforced with 5 to 15 mm size sheets of plastic waste. The three types of plastic used in the study are: low density polyethylene (LDPE), high density polyethylene (HDPE) and polyethylene terephthalate (PET) with 1%, 1.5%, and 2% dosage by weight of aggregates.</p> <p>Obtained Duriez test results testify to a 9% to 30% improvement in moisture resistance for all types of plastic compared to virgin mixture while for LDPE waste plastic type workability test attests an acceptable compaction condition for RAP material with less than 1.5% of waste plastic.</p> <p>Nevertheless, it has been noticed an increase in void index and compaction difficulties starting from 1.5% dosage, resistance to rutting has also improved with the addition of waste plastic, an improvement in fatigue strength was also observed particularly at 2% dosage.</p> </abstract>ARTICLEtrue Composite Bridge Diagnostics and Reconstruction<abstract> <title style='display:none'>Abstract</title> <p>Many bridges in Slovakia are reaching their designed life span these days. Due to frequent errors during the construction of those bridges as well as bad maintenance, steel-concrete bridges are now in a critical state and urgent repairs of those structures are needed. In this article progressive methods of retrofitting existing concrete bridges are shown. In the presented method, the original pillars and original bridge deck will remain in their place, and on the existing deck new composite, steel-concrete bridge deck with encased steel members of progressive shape will be created. This method brings significant cost reduction for such retrofitting and enables the application of increased loads on the bridge.</p> </abstract>ARTICLEtrue of Recycled Polyethylene in Asphalt Mixture<abstract> <title style='display:none'>Abstract</title> <p>Plastics and plastic products have become part of our lives extremely quickly. Although, they make our lives easier in many aspects, at the end of their useful life, especially thanks to the thoughtless actions of people, they are becoming a serious environmental problem. Even though the laws and legislation are still forcing limits of using the plastic products and thus prevent waste, the concept of plastic-free living is probably not going to be reached easily and quickly. Using the recycling technology, we can prepare the recycled material, which represents a new raw material resource. With the right choice of physical-chemical parameters of recycled materials and using a suitable reaction condition we can incorporate them into the asphalt mixtures. Since their introduction the polymer-modified asphalt mixtures have gained in importance during the second half of the twentieth century, and they now play a fundamental role in the field of road paving. Moreover, the use of recycled plastic in such a product will contribute to the technical and economic recovery of secondary raw materials. The use of various recycled material in paving industry is a common practice but needs further research work. Thus, this study aims to the incorporation of recycled plastics into asphalt mixture. The main objective of our work was to find a suitable recycled plastic, which with its physico-chemical and technical parameters is suitable for incorporation into the asphalt mixture. In our study the recycled low-density polyethylene granulate was used, taken from films and various packaging materials. Our preliminary laboratory experiments were based on the possibilities to prepare and characterized the asphalt mixtures containing recycled plastic at different percentage, i.e., 4 %, 6 %, 8 % and 10 % by weight of bitumen. The experimental tests performed in the study were bitumen content, intergranularity, maximum bulk density, water sensitivity and resistance to permanent deformations. The results showed that the mix containing 6 % by weight of recycled plastic has ideal properties and meets most of the criteria that have been set for asphalt mixes. A commercially available polymer of similar chemical composition to the recycled material was used as a reference sample.</p> </abstract>ARTICLEtrue Study of the Physico-Chemical Stabilization of a Loess by Sodium Silicate: Case of Southern Algeria<abstract> <title style='display:none'>Abstract</title> <p>This study focuses on collapsible soil from hyper-arid regions in the south of Algeria (Zeribet El Oued, Biskra). A physical characterization of the studied soil was performed which revealed that the soil samples are loess. After this, an experimental study was done on the influence of the sodium silicate solution (Na<sub>2</sub>SiO<sub>3</sub>) at different doses on the collapse potential (CP) and the microstructure of the material. The microstructure investigation was made through a scanning electron microscope (SEM) observation.The main results of this study show that the treatment of collapsible soil with sodium silicate has led to a significant reduction of the collapse potential, exceeding 87%. An effective treatment is obtained with a sodium silicate solution at the optimal dose of 0.8 mol.L<sup>−1</sup>. The SEM observations have revealed micro-structural transformations which are correlated to changes to geotechnical behavior.</p> </abstract>ARTICLEtrue of Recycled Brick Waste Aggregates as a Sustainable Substitute in Cement Treated Base<abstract> <title style='display:none'>Abstract</title> <p>Recycling industrial waste to obtain secondary raw materials is a key focus of environmental policy and circular economy strategies. One such industrial waste, recycled brick waste (RBW), is characterized by high pollution and low recycling rates. This paper evaluates the effects of graded replacement of various RBW sizes as a substitute for coarse and fine natural aggregate (NA) on the mechanical properties and durability of cement treated base (CTB). The novelty of this study lies in the durability evaluation of four types of CTB, including natural, recycled, and mixed CTB. RBW and NA materials are characterized and compared, and the mechanical properties and durability of CTB with RBW materials are analyzed and compared to CTB with 100% NA. The results show that the mixes containing waste bricks exhibit comparable mechanical characteristics and could be used in layers of pavement foundations. Additionally, the durability of the mixes containing RBW yields better results compared to blends containing NA.</p> </abstract>ARTICLEtrue Urbanism with Eddy3D for Grasshopper<abstract> <title style='display:none'>Abstract</title> <p>The changing climate is a trigger for architects to reconsider the conventional design approach and possibly enrich it with novel approaches brought by the digital age. Sun analysis for urban planning with wind analysis too, proves inevitable for creating comfortable public spaces and built environment in general. When incorporating wind analysis into the process of architectural/urban design, several crucial pre-requisites determine the use of CFD (Computational Fluid Dynamics) simulations: (1) the demand from the client, (2) the time-space needed for the investigations, (3) the powerful enough hardware, and (4) software that enables a fast, user-friendly interface for parametric investigations. Among the benefits of investigating wind speed and flowlines in the digital environment is the possibility to compare design alternatives very quickly and with the same boundary conditions. Moreover, the popular algorithmic software Grasshopper currently enables wind investigation of the geometry directly in the modeling environment without the need to export the file to a standalone CFD software. This way, multiple design options can be investigated once the parametric geometry is prepared, and the digital wind tunnel is set.</p> </abstract>ARTICLEtrue Erosion Estimation of Wadi Medjerda in Algeria Using the Revised Universal Soil Loss Equation (RUSLE) through GIS<abstract> <title style='display:none'>Abstract</title> <p>Water erosion is a major problem in the semi-arid environments of Algeria. In this vein, the objective of this study is to use the Revised Universal Soil Loss Equation (RUSLE) on the watershed of Medjerda which is located at the extreme of the North-Eastern part of the Algerian territory. Based on the crossing of various factors in raster mode under ArcGIS allows the production of diverse thematic maps corresponding to multiple factors: erosivity of precipitations, erodibility of soils, topography, the vegetal cover and the anti-erosive practices. Moreover, the risks’ map of water soil erosion was obtained depending on the combination of the previous thematic maps with four class risks has been made up indicating an average erosion value of 2.68 t/ha/year. However, this value is relatively reasonable in relation to the given rate by the interpretation of the bathymetric measures carried out in the Ain Dalia dam.</p> </abstract>ARTICLEtrue of Takt-Time Planning on Plastering Work Productivity: A Case Study<abstract> <title style='display:none'>Abstract</title> <p>This article aims to analyze productivity issues during the implementation of plastering works on the case study of a residential complex. The results of the study revealed that establishing a proper work schedule and adhering to the Takt schedule resulted in a 19% increase in plastering productivity compared to non-Takt schedules. Furthermore, the study identified the existence of waste, which had a negative impact on the progress of the plastering work and could have been prevented through better project planning during the initial project phases.</p> </abstract>ARTICLEtrue the Assessment of Actual Compressive Strength of Concrete in Reinforced Columns: Influence of Core Diameter and Slenderness Ratio<abstract> <title style='display:none'>Abstract</title> <p>This paper studies the influence of core diameters and slenderness ratio on the assessment of the actual compressive strength of concrete on reinforced-concrete elements. The experiment consists of the preparation of three reinforced concrete columns and the extraction of cores to carry out both destructive (core diameter of 64 mm, 79 mm, and 103 mm) and non-destructive tests. The non-destructive test deals with the propagation of elastic and compressive waves by deriving the ultrasound pulse velocities. The results show that the assessment of the compressive strength of concrete depends strongly on the diameter of cores and the extraction zones. Furthermore, the derivation of the actual compressive strength by referring to the compressive strengths of the cores with a diameter of 64 mm shows a stringent appearance of a size effect. More interestingly, valuable details about the correlation between the concrete compressive strength assessment based on destructive and non-destructive tests are also presented.</p> </abstract>ARTICLEtrue of a Self-Compacting Paste Based on Glass Powder Using Mixture Design and the Desirability Function<abstract> <title style='display:none'>Abstract</title> <p>The partial replacement of cement by supplementary cementitious materials is an opportunity for reducing fossil energy consumption and greenhouse gas emissions. In this study, forty (40) pastes were formulated by applying a 4-factor mixture plan, consisting of cement, glass powder (GP), superplasticizer and water. Third order models “special cubic” established for the flow time, spreading diameter, and flow velocity, responses were statistically significant. The analysis of the models allowed the study of the individual and combined effects of the different factors, highlighting the predominant effect of the superplasticizer on the dispersion GP fines. The multi-criteria optimization allowed the development of two optimal pastes SCP1 and SCP2 incorporating 25 and 7% GP, respectively. SCP1 was chosen because at this GP amount, unlike at 28 days, the paste presents the best strengths at 90 days with 4.5% increase for flexural tensile strength and 15.69% increase for compressive strength while maintaining satisfactory workability.</p> </abstract>ARTICLEtrue of Waste Tire Chips and PET Plastic Flakes in Backfill Behind Retaining Walls<abstract> <title style='display:none'>Abstract</title> <p>The use of waste in the field of civil engineering is one of the solutions to reduce the harmful impact of waste on the environment on the one hand and preserve natural resources on the other. This study aims to investigate the effect of using waste materials such as plastic and tire chips that can be used as backfill in retaining walls. A numerical study has been carried out by using PLAXIS 2D software version 8.6 to model three types of rigid retaining walls, namely: scale wall test, cantilever wall, and gravity wall. In addition, the backfills of those retaining walls are composed of two mixtures. The first is a mixture of sand and tire chips (TC) with different percentages (10%, 30%, 50%, and 70%). The second is a mixture of sand and PET plastic flakes at different percentages (12.5%, 22.5%, and 32.5%). The results obtained from this study confirmed that the use of PET plastic waste and tire chips waste mixed with sand in the backfills of rigid retaining walls contributes effectively to the reduction of horizontal and vertical displacements as well as the earth pressures behind the retaining walls, therefore improving the stability of the retaining walls.</p> </abstract>ARTICLEtrue of Wastewater and Hydrogeneration: Sustainable Land Division Project<abstract> <title style='display:none'>Abstract</title> <p>The present case study - Sustainable Cerrado Subdivision Project in Arouca (Portugal) - proposes the implementation of a design solution that promotes ‘sustainable neighborhoods’, expanding the concept of ‘sustainable homes’. This type of project results from the application of established construction methodologies and innovative solutions, aiming to meet society’s needs with the least possible mobilization of resources (natural, energy, and financial), considering water and energy efficiency as central elements. More specifically, the goal is to reduce the inflows into public wastewater and stormwater drainage systems by changing the consumption habits of the population and collecting rainwater in impermeable areas, as well as treating greywater for non-potable reuse. In water supply systems, there is potential for energy production through microturbines that can harness the energy required for pressure control - hydrogeneration.</p> </abstract>ARTICLEtrue Life Prediction for Reinforced-Concrete Low Domes<abstract> <title style='display:none'>Abstract</title> <p>The study of fatigue of thin reinforced-concrete shells presents a complex modelling approach. This work is devoted to the numerical evaluation of the fatigue life of reinforced-concrete domes, with the concrete class of <italic>C25/30</italic>. For the formulation of a fatigue criterion under a symmetrically alternating load, with a very high number of cycles (<italic>10<sup>6</sup></italic>), the approach begins with the study of mechanical behavior under monotonic loading, related to the fatigue response. The numerical correlation results of the studied cases, based on a conservative fatigue limit of concrete in compression, enables to estimate the service life of these structures, knowing only the response under monotonic loading. The correlation formula proposed in this article can therefore directly estimate the service life of reinforced concrete domes, based on the maximum stress resulting from monotonic loading.</p> </abstract>ARTICLEtrue and Water Quality Simulation in a Drinking Water Supply Network: A Case Study of the Ain Regada Network<abstract> <title style='display:none'>Abstract</title> <p>To ensure the quantitative and qualitative safety of the drinking water supply to urban and rural areas, drinking water supply network managers are always concerned to improve the quality of the service provided to consumers and the continuity and quality of the water distributed. They are also concerned to ensure better management of all water supply systems. The development of computer software has made network modelling an essential part of the design and management of water supply systems. In this context, this study focuses on the operation of the Ain Regada water supply network. The simulation of the operation of the network in its current state is carried out using Epanet software.</p> </abstract>ARTICLEtrue Use of Seismic Isolators to Improve Building Performance<abstract> <title style='display:none'>Abstract</title> <p>The use of seismic isolators is a design method that involves inserting a flexible element at the base of the structure to decouple its movement from that of the ground to reduce vulnerability to earthquakes. They also make it possible to reduce the demand for force and deformation on the various structural elements. The aim of this research is to evaluate the contribution of HDRB high damping elastomeric seismic isolators in the reduction of seismic forces. It also consists in comparing the results of the dynamic analysis of the two fixed base structures in frames or frames braced by shear walls with the isolated structure mounted on an HDRB elastomer system and subjected to the same seismic excitation using the SAP 2000 calculation software. The results obtained showed an attenuation in the accelerations, a lengthening of the period, strong reduction in displacements and a reduction in the shearing force at the base of the isolated structure compared to fixed base structures.</p> </abstract>ARTICLEtrue of Electrical Resistivity Tomography for Joint Geophysical and Geotechnical Landslide Characterization: A Case Study<abstract> <title style='display:none'>Abstract</title> <p>Slope movement processes include complex soil and rock failure mechanisms. Their study benefits from a multidisciplinary approach based on a wide range of information including geological and geomorphological mapping, and geotechnical and geophysical investigations. This research paper focuses on the characterization of the Tamentout landslide that occurs in the southeast of Jijel province. The study area belongs to the Tellian domain in which the geological outcrops are dominated by Senonian formations, composed of marl deposits overlain by Numidian flysch of Aquitano-Burdigalian age, with a sloping topography ranging from 20° to 30°. The geophysical approach consists of processing the available geophysical data of resistivity, obtained by the Electrical Resistivity Tomography (ERT). This study aims to characterize the internal structure, and the changes in water saturation within the unstable mass and locate the depth of slip surface associated with this landslide. Through this work, we combined geological and geotechnical investigations with electrical resistivity tomography (ERT). This combination gave a more detailed image of the substrate geology and structure of the landslide zone. The 2D resistivity results show that the basement consists of two main formations. The first one is a highly conductive formation with a resistivity range between 2 and 25 Ωm, a depth of 0-8 m, and is interpreted as a saturated marl-clay overlaying. The second, a hard and compact formation with a resistivity range between 50 and 200 Ωm and a depth range of 8 to 40 m, was interpreted as a substrate of tellian marls. The presence of boulders of Numidian sandstone within the two formations is materialized by a very high resistivity value ranging from 500 to 1000 Ωm. The slip surface was located on the layer with low resistivity (2-25 Ωm). The precise determination of the depth of the shear zone is of vital use in implementing mitigation measures and carrying out the stabilization work of this unstable zone. Through this work, we will highlight the advantage of the combination of available results of the geological, geotechnical investigations and electrical resistivity tomography (ERT) carried out in the study area.</p> </abstract>ARTICLEtrue Response of CFRP Tensegrity System in a Suspen-dome<abstract> <title style='display:none'>Abstract</title> <p>Wind-induced excitation causes structure to vibrate which leads to instability. This paper focuses on the performance of CFRP tensegrity system in a suspen-dome subjected to wind load by assuming such load as harmonic. A comparison is made with the traditional steel tensegrity system, in order to justify the integrity of CFRP cable application in a suspen-dome system. A finite element software, namely ANSYS, was implemented for the simulation by analyzing a physical model of 4 m span and 0.4 m height. Results show that CFRP tensegrity system has similar performance as steel tensegrity system and can be used as a substitute for steel.</p> </abstract>ARTICLEtrue of Passive Design Strategies on Environment, Cooling and Lighting Energy Demand. A Weighted Least Squares-Based Approach<abstract> <title style='display:none'>Abstract</title> <p>The energy transition requires optimal knowledge of the thermal behaviour of different passive strategies. This paper explores the impact of 28 variables representing 4 shading devices, 5 external wall compositions (<italic>U</italic><sub>w</sub>), 3 window types (<italic>U</italic><sub>w</sub>), 4 window-to-wall ratios (WWR), 4 types of climates represented by 4 cities, and 8 orientations. Applying the Latin hypercube sampling method, a campaign of 300 dynamic thermal simulations is performed to assess the impact of the variables selected using the weighted generalised linear regression method for the energy demand for air conditioning, the energy demand for lighting, and the environmental impact expressed in kg of CO<sub>2</sub>. The model of energy demand for cooling (R² = 0.951) shows that the weather data is the variable that most explains energy demand, followed by the glazing ratio, the thermal characteristics of external walls, and shading devices. The model explaining the energy demand for lighting (R² = 0.945) shows that the WWR and shading devices, the weather data, and the orientation, influence the energy demand for lighting. Finally, the model explaining the embodied carbon footprint (kg of CO<sub>2</sub>) (R² = 0.989) shows that external walls and window type are the main influencing factors. Finally, the best combination for balancing the cooling-lighting-embodied carbon balance equation is discussed.</p> </abstract>ARTICLEtrue of Productivity in Buildings Construction<abstract> <title style='display:none'>Abstract</title> <p>Improving productivity in construction projects has long been a major concern, and much research has been carried out to try to ameliorate construction productivity. To this end, this study aims to improve and increase the productivity rate of flat slab formwork used in residential construction projects. A survey consisting of 150 questionnaires was undertaken to identify the factors that influence on the productivity. Based on the relative Importance Index (RII), data on eleven factors deemed to affect productivity were selected. A collection of 100 data points from various sites were utilized to develop two models. Firstly, an Artificial Neural Network (ANN) model was employed, and secondly, a parametric approach was investigated. The data were divided into two sets, with 70% of the data used for training and the remaining 30% used for testing. The models’ performance was evaluated using the Mean Squared Error (MSE) and Mean Absolute Percentage Error (MAPE) values. In the test phase, the artificial neural network model yielded an MSE value of 2.6610e<sup>−4</sup> and a MAPE value of 4.9227, whereas the parametric model produced an MSE of 0.040 and a MAPE of 9.525. It was found that the artificial neural network model provided reliable prediction accuracy compared to the parametric model. However, the artificial neural network approach can be selected as a robust model in predicting and controlling the productivity rate in local construction projects by using the developed model based on the identified factors.</p> </abstract>ARTICLEtrue