rss_2.0Journal of Applied Engineering Sciences FeedSciendo RSS Feed for Journal of Applied Engineering Sciences of Applied Engineering Sciences Feed Experimental Study on Portland Pozzolana Cement Mixed with Natural Hydrocolloids<abstract> <title style='display:none'>Abstract</title> <p>To make a structure sturdier, the construction materials must be of higher quality. To enhance the structural qualities of fresh concrete, or improve the properties of hardened concrete, additives are added to concrete during the mixing process. To offset the high cost of chemically improving concrete, cost-effective substitutes are needed. Three hydrocolloids found in nature, namely Gum Arabic, Gum guar, and Tamarind kernel powder, have been investigated as potential concrete additives, within a range of 0.25 percent to 1.25 percent in increments, depending on the amount of cement used. The findings of the compressive strength test reveal a progressive improvement following the addition of natural hydrocolloids. Concrete strength reaches its peak at 0.75% of Gum Arabic, 0.50% of Gum guar, and 1% of Tamarind kernel powder. It is found that these hydrocolloids, when combined with concrete, improve its strength. Therefore, they may be used in the percentages specified in this study to control this effect. As an additional benefit, utilizing these hydrocolloids to improve concrete strength eliminates the need for biowaste disposal.</p> </abstract>ARTICLEtrue of Bolts Overloading in Flange-Type Joints<abstract> <title style='display:none'>Abstract</title> <p>The joints of bars composed of flanges and high-strength bolts are currently used in steel structures as simple and economical construction solutions. This paper presents some theoretical aspects regarding the behavior and calculation of joints with flanges and partially pre-tensioned bolts. The overloading of the pretensioned high-strength bolts produced by the tensile effort resulting from the external actions is usually neglected in the technical materials and in the design norms for constructions, as long this tensioning effort does not exceed the pretensioning force of the high-strength bolts. The overloading effort of the bolts can be evaluated theoretically by estimating the relative stiffness of the flanges and bolts and confirmed through experimental tests and computer simulations. This paper also theoretically and computationally analyzes a joint for a tensioned bar made up of pre-stressed high-strength bolts and end flanges.</p> </abstract>ARTICLEtrue of the Non-Linear Rupture of a Section Under Compound Deviated Bending<abstract> <title style='display:none'>Abstract</title> <p>Under stresses close to the ultimate stresses, a reinforced concrete section yields and cracks. The calculation in linear elasticity no longer makes it possible to evaluate the real deformations of the section. One is then led to make a study in nonlinear elasticity. The object of this work is the elaboration of a calculation method in nonlinear elasticity, allowing the simulation until the failure of reinforced concrete sections subjected to a compound deviated bending taking into account the real behavior laws (nonlinear) of the materials (steel and concrete). A computer program is developed following FORTRAN standards, and then confronted with the obtained experimental results on failure tests of sections subjected to deflected bending. The comparison between the numerical simulation and the experimental test/calculation shows the achievement of satisfactory results.</p> </abstract>ARTICLEtrue Theoretical and Practical Protection Methods of Metallic Structures Against the Effects of Corrosion<abstract> <title style='display:none'>Abstract</title> <p>The problems of corrosion and anti-corrosion protection are currently an important area for preventing economic losses and combating environmental pollution. Corrosion-related problems are present in all economic fields, including machine construction, shipbuilding and port construction, chemistry and petrochemicals, metallurgy, water and gas supply systems, energy production systems, transports, etc. Corrosion is a complex process that depends on many factors, related to the variety of technical metal materials and technological environments. This paper can be considered a mini-review that contains some general theoretical aspects related to the corrosion of metals and some case studies from the specialized literature of the last five years, in the field of various technical and industrial constructions based on metal structures.</p> </abstract>ARTICLEtrue Analysis for a Low-Volume Concrete Road with Reinforced Subgrade Subjected to Swelling Pressure<abstract> <title style='display:none'>Abstract</title> <p>This paper presents the parametric analysis of a combined system of a low-volume concrete pavement, base layer and reinforced expansive soil, subjected to the stresses due to wheel loading and swelling of the soil. A soil-structure Interaction model is considered for the analysis, in which the pavement and the reinforcement are idealized as a finite beam, with plane-strain conditions, whereas a base layer and the expansive soil are modelled as Winkler Springs of different stiffnesses. During the analysis, it was taken into account that the geosynthetic reinforcement, which could be in the form of a geogrid, geocell, or a combination of both, possesses bending stiffness and is placed at the interface between the base layer and the expansive subgrade. The reinforcement layer is subjected to stresses due to wheel load, self-weight of pavement slab and surcharge load of the base layer at the top and the swelling pressure from the subgrade at its bottom. The governing differential equations for the flexural response of the model are derived and a closed-form solution is presented in a non-dimensional form. The outcomes of the parametric analysis highlight that the flexural response of the pavement is predominantly affected by the relative stiffness of the base layer and the expansive subgrade. In contrast, the relative flexural rigidity of the upper and lower beams has a comparatively minor impact on the model’s response. Additionally, parameters like the depth of placement of the lower beam, unit weight of the upper soil layer, and the self-weight of the upper beam also contribute to influencing the response of the pavement model. The study suggests that, while designing for the concrete pavement, opting for an increase in the modulus of subgrade of expansive soil may be a preferable choice over reinforcing the foundation of the pavement.</p> </abstract>ARTICLEtrue Comprehensive Evaluation of Tuned Vertical Isolation System for Seismic Risk Mitigation<abstract> <title style='display:none'>Abstract</title> <p>Vertical isolation by dividing the building into two soft and stiff sub-systems benefits from the period shifts and the damping mechanism across the height. However, the displacement demand imposed on the soft sub-system is less applicable in congested urban areas. As a result, in this study, a hybrid system of vertical isolation system benefiting from a tuned soft subsystem divided into upper and lower portions is investigated. A parametric linear 3-Degree of Freedom (DoF) model of the system incorporating mass and frequency ratio of the sub-systems was introduced and analyzed by response spectrum in MATLAB. A closed-form solution for the system frequency and mode shapes was also established. Response spectrum analysis indicates increasing the Tuned Mass Damper (TMD)’s fundamental period to 2.5 times the soft sub-system’s, reduces its displacement to more than 40 percent. The Multi Degree of Freedom (MDoF) model of the system is parametrically generated in MATLAB. Time history analysis of the building subjected to 40 records with 2 and 10 percent probabilities of exceedance in 50 years compared with conventional vertical isolation reveals the lower soft sub-system displacement can be reduced up to 45 percent by shifting drift to upper stories. The innovative tuned vertical isolation by demonstrating superior control performance as comprises lower floors’ drift may be an applicable solution for adjacent high- and low-rise buildings.</p> </abstract>ARTICLEtrue and Artificial Intelligence (AI): How AI Anticipates Human Behaviour in Fire Situations- Case Study of the Colectiv Fire<abstract> <title style='display:none'>Abstract</title> <p>The catastrophic fire at Bucharest’s Colectiv Club marks a profoundly tragic event in Romania’s history, being one of the most significant human-made disasters the country has faced in recent decades. This study seeks to meticulously reconstruct the events of that fateful night through the use of advanced simulation software applications. By doing so, it aims to provide a detailed analysis of the factors leading to the tragedy, which claimed the lives of 64 individuals and caused injuries to 185 others. The objective is to understand better the dynamics and consequences of the fire, potentially leading to improvements in safety protocols and emergency response strategies to prevent such disasters in the future.</p> </abstract>ARTICLEtrue Interface for Electrical Dimensioning of an On-Grid Photovoltaic System<abstract> <title style='display:none'>Abstract</title> <p>Energy is an essential element in the development of mankind and is the engine that has made possible all the discoveries and innovations of recent decades. It is found behind the comfort we have in everyday life, whether at home, at the office, or when traveling: an optimal temperature in the room, light at anytime, appliances to ease us and make our lives more beautiful. An energy system based on renewable energy has the ability to provide electricity in an economical, sustainable, long-term, non-polluting way and can serve the increasing population. One such example is represented by photovoltaic (PV) panels, which produces electricity from captured solar energy and is one of the solutions considered for reducing energy. The dimensioning of a photovoltaic system, from a technical and economic efficiency point of view, involves the analysis of input data, output data and hence the characteristics of an efficient system. The analysis can be done analytically, but also with the help of dedicated software, the result being, in the end, a safe system in terms of preventive operation and maintenance. In the article was made the dimensioning of a system, analytical and automatic – using software application – to determine if the result obtained – the photovoltaic system – is the same regardless of the method used.</p> </abstract>ARTICLEtrue of Rheology in the Area of High-Performance Concrete – A Review<abstract> <title style='display:none'>Abstract</title> <p>The rheological or flow quality high-performance concrete (HPC) are significant as they affect several parameters, including ease of placing, compatibility, durability and strength. For the selection of component materials and prediction of the fresh and hardened characteristics of HPC, an adequate understanding of rheology is required. This literature review gives a gist of the works done in the field of rheological study of HPC. The flow models and equations to explain the flow behaviour of HPC mixes as proposed by the researchers are presented. Yield stress and plastic viscosity are the basic rheological parameters that are used in these equations. Various rheometers developed to measure and estimate these rheological parameters of HPC are also presented in this paper. This review provides a thorough analysis of the effects of various constituent materials on the rheological properties of HPC. This includes aggregates, cement, various supplementary cementitious materials like fly ash silica fume, slag etc. Also, the effect of mineral admixtures like superplasticizers and viscosity modifying agents along with the synergic effects is discussed. Finally, the prospects of the study on the unexplored areas and future challenges in the field of study are discussed.</p> </abstract>ARTICLEtrue Method Consistency Analysis in the Creation of Digital Terrain Models<abstract> <title style='display:none'>Abstract</title> <p>The present paper proposes to analyse the consistency of several interpolation methods for generating a grid structure, which will be used for digital terrain modelling in the case of water retention basins (polders). The aim is to use a single dataset, from which a number of measured points will be eliminated, after which several interpolation methods will be applied to the remaining dataset in order to analyze which method yields the nearest correct (measured) value. The research focuses on comparing the reliability, consistency and sheer data accuracy (in comparison with pre-determined control points) of both the resulted grids and the noise filtered ones, to assess the performance of each method.</p> </abstract>ARTICLEtrue on the Influence of Temperature and Frequency on the Stiffness Module for Airport Asphalt Mixtures<abstract> <title style='display:none'>Abstract</title> <p>The study of the behavior of bituminous mixtures is a very old subject in the specialized literature, many specialists in the field trying to explain the causes of the degradations, considering different factors. The bituminous mixtures were initially used in the construction of road structures for roads, so that a few years ago they also started to be used in the road structures of airport surfaces.</p> <p>The subject of the current research study is a priority worldwide and contributes, through the obtained results, to the enrichment of knowledge regarding the behavior of airport bituminous mixtures. The complexity of this study was based on the multitude of laboratory tests carried out on the designed airport bituminous mixture, BBA 16, using complex modern and high-performance equipment and equipment that lead to the determination of the stiffness modulus at different temperatures and frequencies both on trapezoidal samples and on prismatic samples.</p> </abstract>ARTICLEtrue Performance and Mechanical Behavior of Pet Fiber Reinforced Recycled Fluid Concrete<abstract> <title style='display:none'>Abstract</title> <p>Many environmental problems can be attributed to various sources, such as the demolition of old buildings, waste from bricks, glass waste, among others, which are generated worldwide. This waste is converted and recycled as natural aggregate. On the other hand, a significant issue with concrete incorporating Recycled Concrete Aggregate (RCA) is its inferior properties compared to natural aggregate concrete. The subpar properties of RCA concrete can be enhanced by the addition of Fibers. This research examines the effects of polyethylene terephthalate fiber (RPETF) and recycled fine concrete aggregates (RFCA) on the mechanical properties and durability of self-compacting concrete (SCC). Three concrete families were created: one using RPETF alone, one using RFCA alone, and a third utilizing both RPETF and RFCA combined. The natural fine aggregates (NFA) were replaced with RFCA in increments of 25% from 0% to 100%. The results showed that the split tensile strengths of the mix of 100% RFCA and 1.2 % RPETF have improved over time by 28% compared to the mix with 100% RFCA alone. However, the inclusion of RPETF in SCC mixtures with varying amounts of RFCA resulted in reduced durability of the composite.</p> </abstract>ARTICLEtrue of Concrete Slabs Reinforced by Recycling Waste<abstract> <title style='display:none'>Abstract</title> <p>This study aims to experimentally evaluate the mechanical properties of concrete slabs reinforced with two types of fibers: metallic fibers (MF) and grids based on polypropylene fibers (PPG). The metallic fibers, sourced from machining waste of steel parts, are randomly distributed in the concrete, while the polypropylene fibers are arranged in grids. The investigation includes punching tests conducted on slabs measuring [25x50x7] cm³, as well as compression tests on cylinders with a diameter of Ø16 cm and a height of H32 cm. Mechanical resistance and tearing characteristics of the fibers were also assessed. The concrete’s composition was determined using the experimental “Dreux-Gorisse” method. Five different metal fiber contents (MF) were studied (W=0.2%, W=0.4%, W=0.6%, W=0.8%, and W=1%), alongside a control concrete sample (BT) with no fibers (W=0%) having the same composition as the matrix. Two variants of grids based on small-mesh polypropylene fibers (PPG/SM) and large-mesh (PPG/LM) configurations were considered. The comparative analysis of the results highlights that, at a fiber content of W=0.8%, metallic fibers (MF) enhance both resistance and rigidity more effectively than polypropylene fibers in small meshes (PPG/SM) and large meshes (PPG/LM), thereby limiting the formation of puncturing cracks.</p> </abstract>ARTICLEtrue Interaction in the Reinforced Concrete Frames-Wall<abstract> <title style='display:none'>Abstract</title> <p>Reinforced concrete frame-wall (RC frame-Wall) structures are generally solved in a global manner by modeling the entire structure by assembling the RC frame and wall stiffness matrices into a global matrix. The bar-wall element interface is modeled at the mean line of the beam-column element, according to RPA 99, which limits the interaction to the axial and transverse components of the forces (mechanical and kinematic) thus neglecting the effects of section rotations.</p> <p>In order to take into account, the rotational components of the mechanical behavior of the beams (section rotation and bending moment), the interaction between the RC frame and the wall must take place at the real interface of the two substructures, i.e. at the extreme fiber of the bar elements (beams and columns). The transmission of force from the wall to the RC frame is done by transforming the tangent stresses of the wall into moment in the beam.</p> </abstract>ARTICLEtrue Importance of Ground Control Points In A Photogrammetric Workflow<abstract> <title style='display:none'>Abstract</title> <p>This study investigates the optimal distribution and pattern of ground control points (GCPs) in aerial photogrammetric projects. Aerial triangulation (AT), also known as bundle adjustment, is the fundamental step in refining 3D reconstruction models and camera positions, thereby minimizing reprojection errors. The study utilizes data from a national project in Romania, employing high-resolution aerial images acquisition using photogrammetric sensors. The project has rigorous requirements of ground control points (GCP) placement and field measurements using GNSS and geometric leveling techniques. The study employs various scenarios, manipulating the number and distribution of GCPs, to assess their influence on planimetric and altimetric accuracy. Results indicate that the configuration and number of GCPs significantly affect the accuracy of photogrammetric products, such as dense image point clouds, digital surface models, and orthophotos. Moreover, the study underscores the importance of precise GCP determination methods, especially in regions lacking a precise gravimetric geoid model. In scenarios with inadequate GCP coverage the outcomes have inferior quality, emphasizing the critical role of GCPs in ensuring the quality of photogrammetric products. Overall, the research gives a clear view on the best placement patterns of GCPs and their influence on AT process evaluation performed in check points (CHKs).</p> </abstract>ARTICLEtrue Rinex Data Files Using the Python Programming Language<abstract> <title style='display:none'>Abstract</title> <p>The techniques and tools developed for geodetic determinations have made it possible, over the past half century, to carry out measurements using global navigation satellite systems. As the accuracy and precision of positioning solutions, such as Fast Static and RTK, improve through technological advances, more applications will become available that can provide users with positioning information over time, autonomously verify the integrity of transmitted data, and ensure sufficient accuracy for their intended purposes. In our study for the interpretation, analysis, and visualization of raw and/or processed RINEX GNSS data recorded over time at a geodetic point using the information available from the Fast Static technique, we used the GeoRinex library from the Python programming language. This library converts data to set, for easy use in processing parameter sets, from Rinex files: of ROMPOS reference stations and of the new B10 point resulting from measurements using the Fast Static technique: pseudorange (C1, C2, P1, P2....), carrier phase (L1, L2,…), doppler (D1, D2....) and signal strength (S1, S2....). All this information will help us to analyse and interpret the degradation of the parameters associated with Rinex version 2.11 epoch positioning files 12.02.2023, time interval 12:00-14:00 (fast static) and to understand their accuracy and behavior in different environments. Based on this study, our aim was to evaluate the error in determining the positioning accuracy of the B10 point located in a crowded and heavily trafficked area, which allows sufficient coverage of the GNSS satellites.</p> </abstract>ARTICLEtrue Simulation of Improving the Efficienty of Photovoltaic Thermal Panels<abstract> <title style='display:none'>Abstract</title> <p>The need to optimize the operation of photovoltaic modules inevitably arises with the development of green energy production technology. In order to achieve a good technological yield, durability and efficiency in production, continuous studies and innovations are required. This study focuses on simulating the operation of water-cooled and uncooled PV modules in order to understand the temperature-dependent PV operation. This cooling module consists, in the first phase, of a copper coil through which water circulates, and in the second phase, of a coolant distributor/collector system. The module is attached to the lower surface of the photovoltaic panel, respectively to the teller foil layer. For this simulation we used the Ansys software package (Discovery, Fluent and Space Claim).</p> </abstract>ARTICLEtrue of Gate Type in the Air-Demand Ratio in Closed Conduits<abstract> <title style='display:none'>Abstract</title> <p>Sluice and radial gates are common devices used to control flow in closed conduits. In high-head gated conduits, the high-velocity flow exiting the gate drags and entrains a lot of air. If the air demand of the flow is not met, the pressure drop downstream of the gate will cause structural damage or cavitation. Typically, an air vent is installed immediately downstream of the gate to supply sufficient air to the flow. In this study, the effect of the conduit gate type on the air-demand ratio was investigated. The results showed that the gate type had a very significant effect on the air-demand ratio. Significantly higher air-demand ratios were observed in the conduit with a sluice gate compared to the conduit with a radial gate. The results obtained will be useful in future modeling and design processes.</p> </abstract>ARTICLEtrue of Asphalt Mixture Fatigue Behaviour Using the Two-Point Bending Test<abstract> <title style='display:none'>Abstract</title> <p>The fatigue behaviour of bituminous layers must be taken into account when dimensioning road structures and projecting streets. To satisfy this fatigue criterion, laboratory tests must be used to determine the material characteristics and fatigue life of bituminous mixtures. The aim of this article is to study the crack initiation stage using a specific laboratory test: the two-point constant strain bending fatigue test on trapezoidal specimens. The laboratory tests were carried out on three types of bituminous mixes used in the wearing course, each containing successively two different types of bitumen (one imported and one Romanian). The conclusions drawn from this article refer to the influence of mix type and bitumen on the characteristics obtained.</p> </abstract>ARTICLEtrue Thermo Mechanical of Wasteglass Powder Reinforced Concrete Beam Subjected to Fire Loads<abstract> <title style='display:none'>Abstract</title> <p>Waste Glass Powder (WGP) could be used as a cement replacement additive to manufacture concrete and solving the problem of environmental pollution. This article presents a numerical modeling of the thermo-mechanical behavior of a reinforced concrete beam based on an addition of 20% of the powder glass as a substitute for cement powder with modeling of concrete-steel contact using ANSYS software. To do this, a reinforced concrete beam based on glass powder is modeling in three dimensions by the finite element method (FEM) and it is subject to thermal loading during 2 hours in order to simulate the thermo thermo-mechanical response of the beam element. ANSYS provides a three-dimensional element (SOLID65) with the nonlinear model of brittle materials similar to the concrete materials. The element features a smeared crack analogy for cracking in tension zones and a plasticity algorithm to take into account the concrete crushing in compression zones.</p> </abstract>ARTICLEtrue