Band 31, Heft 1

Avian eggshell is a natural biomaterial that has been used as an alternative natural source of CaCO 3 and is accessible in big amounts from egg manufacturing. This study was planned to estimate CaCO 3 in quail’s eggshell because it has a probable use in the progress of a novel choice of many applications. Physical properties: mineralogical documentation of the natural eggshell nanoparticles were approved using XRD and FTIR to explore the chemical bond or molecular structure of the materials. Micrographs were obtained using FESEM/EDX and TEM to identify the morphology and size of nanoparticles. The results showed that quail eggshell was soft, with white to light sand color, and a smooth texture which allows good deposition of different color spots, from black to brown spots. The resulted of eggshells signifies almost 8.4% w/w of the overall weight (12.2) gram of quail egg and 91.60% w/w of the micropowder to the full weight of (0.94) gram of quail eggshell. The results presented that calcium is the main element in an eggshell; frequently occurs in a formula of CaCO 3 and the crystal construction was almost pure calcite. FTIR spectra for quail eggshell demonstrated the existence of the out of plane bending, the asymmetric stretching, and the plane bending styles of the carbonate groups, specific of normal dolomite, situated at 873 cm –1 , 1405 cm –1 , and 710 cm –1 , respectively. The FESEM and TEM for nanoparticles were shown calcite CaCO 3 nanoparticles with an ordinary size of ≤ 100 nm for FESEM and with a variety size of ≤ 50 nm for TEM. Unfortunately, eggshell is an egg product manufacturing deposit. These incomes will let fast developments in proportional studies of the organic elements of avian eggshell and their purposeful consequences by usages of eggshell in nourishment and medicine which can be applied for many resolutions that diminish their consequence on environmental contamination.

Materials with high hardness are usually preferred in armour applications and are difficult to weld due to high Carbon Equivalent (C.E). In this investigation, an attempt was made to weld Ultra-high Hard Armour (UHA) steel (having C.E of 0.91) by Shielded Metal Arc Welding (SMAW) process using three electrodes (i) austenitic stainless steel (ASS- E307-16), (ii) super duplex stainless steel (SDSS-E2594-16) (iii) low hydrogen ferritic (LHF-E12018M-low-alloy steel electrode). The mechanical properties (tensile, impact toughness, and microhardness) were evaluated and correlated with microstructural features along with Cr eq /Ni eq ratio of weld metal. The joints fabricated using LHF electrodes showed superior strength of 962 MPa and hardness of 341 HV. The joints made using ASS electrode showed superior impact toughness of 72 J and Notch Strength Ratio (NSR) of 1.32 due to the higher energy absorption capability of the austenitic phase. At the weld interface, joints fabricated using ASS and SDSS electrodes show the unmixed zone (UMZ) and martensitic band (MB) due to sudden change of crystal structure (Face Centred Cubic (FCC) / Body Centred Tetragonal (BCT)). It is also found that the strength property increases (651 MPa to 856 MPa) with an increase in Cr eq /Ni eq ratio (1.87 to 3.2) of weld metal and with a decrease in ductility.

A more durable rail track structure is fundamental in the railway industry, allowing the government to operate the train with higher speed and axle load. That means more passengers and better quality of railroads travel, thereby reducing the maintenance costs and ensuring passengers’ comfort and safety. The effect of a sub-ballast and asphalt layer thickness and freight train traffic with low operational speed on mechanical behavior and design life of conventional track and asphaltic underlayment track, are presented in this paper. One of the significant findings to emerge from this study is that an AC layer with minimum thickness of 0.20 m is required in the asphalt underlayment track application for Indonesian railway infrastructure to facilitate Babaranjang freight trains with up to 50% more tonnage. The evidence from this study also suggests that the asphalt underlayment track with 0.20 m thick of AC layer that contains grade PG70-28 binder could be beneficial to be applied in Indonesian railway system so that the rail track could be constructed with less volume of works than the regular Indonesia's conventional track with 0.40 m of sub-ballast layer.

Based on the results of standard penetration tests (SPTs) conducted in Al-Basrah governorate, this research aims to present thematic maps and equations for estimating the bearing capacity of driven piles having several lengths. The work includes drilling 135 boreholes to a depth of 10 m below the existing ground level and three standard penetration tests (SPT) at depths of 1.5, 6, and 9.5 m were conducted in each borehole. MATLAB software and corrected SPT values were used to determine the bearing capacity of driven piles in Al-Basrah. Several-order interpolation polynomials are suggested to estimate the bearing capacity of driven piles, but the first-order polynomial is considered the most straightforward. Furthermore, the root means squared error (RMSE) for all suggested polynomials are roughly the same. The production of thematic maps demonstrates the variation in bearing capacity of driven piles over the entire territory of Al-Basrah governorate in correlation with different depths. The results of the statistical equations showed that there is good agreement with those obtained from the SPT data. When compared with the observed values from SPT, the allowable bearing capacity results for the driven piles ranged from (−3 to +38)%. The main results of this study showed a variation of 30% between calculated and estimated values of bearing capacity of driven piles for all lengths of piles at a 95% confidence interval.

The main objective of this research paper is to study the microstructural features and mechanical properties of resistance spot welded advanced high-strength steel of dual phase grade in lap joint configuration which is mainly employed in sheet form for fabrication of the automotive structure. Resistance spot welding (RSW) being a solid-state welding (SSW) process is used to overcome the problems in fusion welding of AHSS-DP steel such as heat affected zone (HAZ) softening, solidification cracking and distortion which significantly deteriorates the mechanical properties of AHSS-DP800 steel joints. The straight lap (SL-TSFL) and cross lap tensile shear fracture load (CL-TSFL) of spot joints were evaluated. Optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques were used to characterize the weld nugget. The X-ray diffraction (XRD) results are also presented for phase identification in the weld nugget. The fracture surface of failed TSFL specimens was analyzed using SEM. The lap joints made using RSW disclosed superior SL-TSFL, CL-TSFL, and WNZH of 21.7 kN, 17.65 kN, and 589 HV 0.5 The superior joint strength and hardness of the weld nugget zone are correlated to the evolution of lath martensite in the nugget zone.

Due to their characteristics such as weight/strength ratio and absorbed energy, the widespread use of composite materials in the last decades engorged the companies to exploit these materials invariant applications like the aerospace, automobile, and marine hull. However, there are some obstructs to the use of these materials that may constrain that. This came from the fact, that composite materials suffer from different damages modes that occur during loading and can be lead to catastrophic failure in their structure, such as intralaminar and interlaminar damage. Consequently, this motivated the researchers to study its behavior considering different damage modes and at different loading states. This work performed a finite element simulation using the Abaqus program of low-velocity drop impact for epoxy reinforced with Kevlar 49 and Ultra High Molecular Weight Polyethylene (UHMWPE) with different thicknesses and number of layers. A user-defined material VUMAT subroutine-based progressive damage model, and the Hashin failure criteria implemented in Abaqus Explicit finite element code had been utilized in this work. In Addition, the interlaminar damage models depend on the cohesive zone model (CZM). The numerical simulation results were compared with the experiments data to confirm the reliability of the numerical model.

This paper experimentally and numerically investigated the impact test response and characteristics of circular honeycomb cores. The experiments were conducted on two different structures of aluminum-tube honeycomb core, square structure and star structure. The specimens were tested in order to find energy absorption, specific energy absorption, and crashworthiness behaviors. The results revealed that circular honeycomb cores with star structure could resist higher impact load than circular honeycomb cores with square structure. In addition, the larger tubes showed a lower impact load the smaller tubes. It was also revealed that the greater the collapse distance of the aluminum-tube honeycomb core, the lower the load. Moreover, FEA simulation results, through ABAQUS.CAE, were compared to the experimental results. The results revealed that good agreement was achieved between the experimental results and the FEA results. The comparison results showed that the difference in maximum load between experimental and FEA model was 0.47–11.84%, which is a reliable analysis result. In terms of energy absorption and specific energy absorption, the difference in maximum load between experimental and FEA model was 23.54% and 16.23%, respectively.

The cast method was used to synthesize cellulose acetate (CA)/titanium oxide (TiO 2 ) composites by varying TiO 2 particle sizes at different weight ratios of 1, 1.5, 2, 2.5, and 3 wt%. The relationship between structural diversity and performance was explored. Microstructures and chemical composition of as-prepared composite films were revealed using field-emission scanning electron microscopy and Fourier-transform infrared spectroscopy. The tensile strength increased from 46.8 MPa for pure CA to 54.7 MPa for the CA-1% micro-TiO 2 composite and 81.7 MPa for the CA-2% nano-TiO 2 composite, according to the mechanical properties. The tensile strength decreased due to some degrees of agglomeration of filler particles above a critical content. UV-vis transmittance spectra showed that pure CA was almost transparent, CA-micro-TiO 2 films were less transparent than pure CA, and CA-nano-TiO 2 films could efficiently block the light. XRD diffraction for the synthesized membranes was performed. The patterns of micro-TiO 2 and nano-TiO 2 were shown as 2 θ = 25° for the anatase phase and 2 θ = 18.5 for the pure CA film, respectively. The hydrophilicity of films was also measured using the sessile drop technique. The contact angle value for the pure CA was 61.3°. As the amount of TiO 2 added to the films increased, the contact angles of the CA-micro TiO 2 and CA-nano TiO 2 films reduced from 53.2° to 29° and from 51.5° to 27°, respectively. The produced films’ improved wettability indicated that these films could be employed as filters.

Fuel based on hybrid green material is of paramount importance for various military and civilian purposes. This work presents a novel expert-based multi-criteria hierarchy and decision-making model to evaluate various chemical rocket propulsion technologies with different fuel material types under an uncertain environment. This helps select the most appropriate fuel material types according to the performance requirements considering various evaluation criteria toward achieving better performance economic benefits of the sustainable hybrid green material-based fuel for various applications. Here, the analytical hierarchy process model was utilized to enhance more informative decisions from both numerical and linguistics information regarding the performance of the fuel based on hybrid green material under an uncertain environment. The model considers various simultaneous evaluations and conflicting criteria to practically demonstrate economic, technical, and sustainable issues for the decision makers in this field. Results demonstrate that cost and size criteria are the most important in the evaluation process from experts’ points of view for the rocket propulsion technology. The fuel based on hybrid green material has the highest priority regarding the whole evaluation criteria. The sensitivity analysis illustrates the robustness of the model as well as the reliability of the drawn decisions.

Purpose Recoil length minimization is always been a top concern in various structural, industrial, and defence applications. The traditional passive recoil system is not able to respond quickly to the changes in the impact force. These limitations can be overcome by introducing a semi-active recoil system, which comprises an intelligent fluid damper. Design, methodology, and approach The electrorheological (ER) fluid, which responds to the applied electric field and exhibits high yield strength, will be a proper damper for the recoil system. An ER damper can bring back the vibrating system to its equilibrium in a brief period. In this article, the general design procedure of an ER fluid semi-active damper has been developed, which is suitable for a recoil system. The equations of damping forces (viscous, quadratic, and ER) are modified in terms of geometric parameter, namely the piston diameter ( D P ), which can be selected to obtain the desired dynamic range (greater than two) and optimum damping force. With the MATLAB software, the damper and spring specifications are fixed to meet the required conditions, viz. the dynamic range should be greater than two, and the total damping and spring force should counter-recoil the system. Findings Results obtained for a case study of gunfire conclude that the recoil system developed using design specifications exhibits desired performance with maximum recoil of 75.59 mm at 80°, angle of elevation, which is within the allowable range of 150 mm. It is shown that the rate of firing can be increased by decreasing the recoil length. Originality and value The novel procedure for the design of ER damper outlined in this work will be helpful for any recoil length minimization problem.

Rim wheel testing through the SAE standard is necessary for driving safety. This study focused on rim wheel tests carried out using the dynamic radial fatigue test method, which has been included in the SAE standard using Fusion360 for the design and ANSYS for the simulation. With different parameters for the rim wheel type, only some parameters of the tested rim wheels were able to pass the standardization by SAE; 16 rim wheels passed the test, while the other 11 rim wheels did not pass. Simulation results suggested that variations in the thickness, geometry, and material affected the displacement of the safety factor, which was inversely proportional. In addition, the variation in the rim wheel produced a change in the safety factor due to changes in its mass and cost, which were directly proportional. The results of this study will aid in rim wheel design, not only in terms of achieving the best performance but also with regard to cost efficiency.

In the current context, an attempt is being made to improve the electrical discharge machining (EDM) process by using powder particles in a suitable combination. To improve the quality of such procedures, the process parameters should be optimized. The present study proposes to utilize Taguchi–Grey relational analysis to discover the optimal combination of process parameters for SKD61 die steel specimens using titanium powder-mixed EDM (PMEDM). Among the machining parameters chosen, the optimal combination of current (3 A), pulse on-time (37 μs), pulse off-time (37 μs), and powder concentration (4 g/L) was determined experimentally. Due to its relevance in spark energy production, peak current is a more significant factor in PMEDM processes. A superior surface topography was obtained with increased microhardness and fewer microfractures over machined specimens with optimal process parameter in PMEDM. The titanium particles can effectively enhance the surface performance measures during PMEDM-based machining owing to tiny craters and pores with better lubrication.

Stainless steel (SS304) is a widely used material in underwater nuclear applications due to its superior corrosion resistance and high strength. Along with these superior properties, the application demands neutron absorption and high wear resistance under dynamic operations. The ceramic reinforcements help to enhance these properties of metal alloy with a suitable composite design. The present work deals with the development of high wear-resistant and radiation (nuclear) tolerant boron carbide (B 4 C)–SS 304 composite material. SS304 metal matrix with 0–5 vol% of B 4 C ceramic reinforcement is produced by powder metallurgy technique. The presence of reinforcement was confirmed with X-ray diffraction analysis. Properties such as density, hardness, and water absorption are measured. A pin-on-disc tribology study is conducted to evaluate the coefficient of friction and wear of developed compositions at a sliding distance of 200 m, contact load of 10 N, and sliding speed of 1 and 5 m/s under dry lubrication conditions. The lowest density of 2.96 g/cc was noted for 15% B 4 C-reinforced composite as compared to the density of SS304 metal matrix (5.71 g/cc). The water absorption capacity of the composite was increased with percentage reinforcement, and it was found 62% higher than the unreinforced matrix. The hardness of composite increases with B 4 C particle reinforcement and maximum microhardness of 153 HV was measured for 15 vol% reinforced composites. Wear and coefficient of friction decrease with an increase in the percentage of B 4 C particles. At 15 vol% of B 4 C in the composite, lowest wear (1.91 mm 3 @1 m/s and 2.51 mm 3 @5 m/s) and COF (0.021@1 m/s and 0.042@5 m/s) were observed. This suggests that the developed composite can be effectively used in low-pressure–high-speed nuclear applications.

In this article, the load resistance and energy absorptions of thin-walled structures on the square tube were numerically evaluated by the finite element method. This structure can be widely used in automotive industries, industrial buildings, ships, offshore platforms, and airplanes. In the finite element method, thin-walled structures on square tubes were examined with different wall thicknesses and materials. The materials used are mild steel, SAE 1045 steel, and SAE 1008 steel. Using the numerical results, the thickness of the wall influences the strength of the structure. Moreover, SAE 1045 steel material also seems to increase the strength of the tube under axial loading compared to the mild steel and SAE 1008 steel material. It is also important to remember that the finite element solution depends on defining your mesh size and boundary conditions. The mesh size is also compared and assessed.

Novel superabsorbent polymers (SAPs) were created by solution polymerization at ambient temperature using potassium polyacrylate (KPA), polyvinyl alcohol (PVA), and magnesium chloride as a cross-linking agent with different weights of 0.4, 0.5, 0.6, 0.7, 0.8, and 1 g for KPA and 0.33, 0.44, 0.55, 0.733, and 1.1 g for PVA. Fourier transforms infrared (FTIR) and UV-Vis spectroscopy were used to determine the chemical composition of the SAP complexes. The outcomes revealed that the KPA and PVA successfully interacted with the magnesium chloride. The morphology of the surfaces shows a uniform porous interconnected microstructure as revealed by field emission scanning electron microscopy. The effective preparation was confirmed by thermal characterization (thermogravimetric analysis and differential scanning calorimetry) of the SAPs. The influence of the cross-linker agent on the SAPs’ water absorbency was examined. The magnesium polyacrylate (Mg-PA) (0.6 g of MgCl 2 ) SAP has a maximum swelling capacity of 650%, while that of magnesium polyvinyl alcohol (Mg-PVA) (0.55 g of MgCl 2 ) was 244%. The findings confirmed that the SAPs have excellent swelling and water-retaining capabilities. The strategy used in this investigation may function as a model for developing and widespread usage of SAPs in agriculture and horticulture.

Composites have been evolved rapidly due to their unique performance in comparison with other conventional materials, such as metals. Although additive manufacturing (AM) has attracted considerable attention in recent years to produce reinforced complex composite structures as in reinforced carbon fiber composites, it is difficult to control the fiber content concentration within the composites to obtain tailored materials properties, especially at high loads of fibers. In fact, high load of fibers usually leads to technical issues, such as nozzle clogging and fiber agglomeration that hinder the 3D printing process. Therefore, a customized artificial neural network (ANN) system was developed in this work to predict the mechanical characteristics of 3D printing thermoset carbon fiber composites at any carbon fiber concentration. The developed ANN system was consisting of three model techniques for predicting the bending stress as well as the flexural modulus of the thermoset carbon fiber composites, even when handling small experimental datasets. The system architecture contained connected artificial neurons governed by non-linear activation functions to enhance precise predictions. Various schemes of ANN models were utilized namely: 1-4-1, 1-4-8-1, and 1-4-8-12-1 models. The developed models have revealed various accuracy levels. However, the 1-4-8-12-1 model has demonstrated a very high level of predictions for the mechanical performance of the AM epoxy/carbon fiber composites. This would enhance predicting the performance of such composites in 3D printing with very minimal experimental work to optimize the fiber content for the desired overall mechanical performance.

This study aims to assess the effect of the solder joint array layouts, including full and peripheral designs, on the mechanical response and reliability of electronic packages subjected to shock and impact loadings. Linear and nonlinear finite element simulations using the global-local modeling technique are employed to perform the analysis. Several peripheral array configurations are considered and compared to the full array systems. The results showed that, for optimum electronic package designs in terms of reliability and cost, it is highly recommended to use peripheral packages having three or four rows of solder interconnects in electronic systems under shock and impact loadings.

In this article, experimental studies on the flexural behavior of concrete beams with corroded reinforcement were conducted. The beams were subjected to simultaneous different load levels and immersed in NaCl solution for 30 days with accelerated corrosion. A four-point bending test was subsequently carried out to determine the loading capacity of these beams. Experimental data show that the loading capacity of the beam decreases as the level of preload increases. The mass loss of steel bars in the beams increases as the level of preload increases. The loading capacity and steel mass loss of the beams subjected to 0.8 of failure load of the non-corroded beam decrease by 32.7 and 30.3%, respectively. The numerical investigation was also done to evaluate the loading capacity with various corrosion degrees of steel bars.

The shape of the projectile seems to determine the effect of a ballistic impact and failure mechanism. In this study, the numerical analysis of ballistic impact with different projectile shapes, i.e ., ogive, blunt, conical, and hemispherical is performed. The target is a circular sandwich plate with an outer diameter of 315 mm, which is composed of three layers with a thickness of 1 mm for each layer. These layers will be filled with different materials such as 1100-H12 aluminum alloy, ZK61m magnesium alloy, and 6061-T651 aluminum alloy. The target plate in the numerical analysis consists of two parts: the inner and outer zones. In the inner zone, the selected element size is set to fine, while in the outer zone, it is set to be coarser, and the size will increase along with the direction and the diameter of the circle. This numerical simulation uses the Johnson–Cook material model and is applied to ABAQUS/Explicit software. The simulation configurations are validated based on previous experiments by comparing the residual velocity values after the projectile has penetrated the target plate. The simulation results will obtain energy absorption values for each variation of the target plate. The energy absorption values are affected by stress and strain in radial, circumferential, axial, and shear deformation. The energy absorption value determines the strength of each variation of the target plate. Then the target plate will compare which arrangement is the strongest when receiving ballistic loads. Graphical abstract

The potentials of CuZnAlNi shape memory alloys to serve as viable reinforcement in Aluminium matrix composites (AMCs) was investigated. The AMCs were double stir cast developed, containing 4, 6, and 8 wt% CuZnAlNi particles; and their structural characteristics and mechanical properties were compared with that of the unreinforced Al alloy and AMC containing 8 wt% SiC. Scanning electron microscopy and X-ray diffraction results show that the CuZnAlNi refined the grain size, and increase in the CuZnAlNi wt% resulted in the formation of varied AlCu-based intermetallics, apart from the primary Al rich phase. The strength indicators – hardness, ultimate tensile strength, and specific strength largely improved with increase in the CuZnAlNi wt% and were comparatively higher than that of the unreinforced Al alloy and AMC reinforced with 8 wt% SiC for the 6 and 8 wt% CuZnAlNi reinforced AMC (specific strength being the only exception). The percentage elongation and fracture toughness values of the AMCs reinforced with CuZnAlNi (12–14.5% and 10.5–12.3 MPa m 1/2 ) were equally superior to the SiC reinforced AMC (9% and 6.5 MPa m 1/2 , respectively). However, a partial reduction in the % elongation was observed with the increase in the CuZnAlNi wt%. Improved matrix/particle interface bonding, matrix refinements, thermoelastic-induced compressive residual stresses, inherent ductile, and tough nature of the SMA were advanced as mechanisms responsible for the improvements in properties.

With the increased emphasis on the need to use recyclable bio-based materials and a better understanding of the mechanical properties of laminated bamboo, there is currently a great deal of interest in developing a new generation of low-cost bamboo-based composites for use in fishing vessels. Laminated bamboo composites (LBCs) comprised of Apus bamboo ( Gigantochloa apus ) and fibreglass mats were investigated to obtain the mechanical characteristics. The LBC with 45°/−45° cross-fibre directions combined with chopped strand mat fibreglass was developed under different layers and mass fractions with the same composite thickness. The influence of different numbers of laminated bamboo layers (3–7 layers) on several mechanical testings, including impact tests using ASTM D256, bending tests using ASTM D7264, tensile tests using ASTM D3039, V-notched beam test using ASTM D7078, and lap shear tests using ASTM D5868 standard, were carried out. The result showed that the strategy in improving the strength properties of LBCs could be achieved by using a thinner bamboo lamina with a higher number of bamboo layers. It was found that bamboo composites with 7 layers with a higher epoxy mass matrix had superior mechanical properties than those with 3 and 5 layers at the same thickness. Another finding revealed that adding fibreglass mat to current LBCs improved mechanical properties compared to previous research, explicitly bending strength increased by about 4.02–7.56% and tensile strength in the range of 12.44–17.73%. It can be found that only specimen with 7 layers fulfils the Indonesian Bureau Classification’s bending and tensile strength threshold.

In this study, singularity fields at the interface corners of piezoelectric-brass unimorphs are investigated. Two models differing in side surface geometry (step and flat surfaces) are analyzed to study the singularity effect on mechanical (stress–strain) and electrical (electric potential and intensity) behavior. A mixed-mode mechanical boundary condition is applied for analyzing the realistic application of unimorphs, with normal force, shear force, and bending moment as internal forces. The conservative integral together with a three-dimensional finite element analysis is used to determine the intensity of singularity. There are three singularity terms at each vertex and singular line. All singularity terms are investigated in detail. Intensities of the singularities at the vertex and several points located on side surfaces (singular lines) are examined. Results show that the intensities of singularities for mixed-mode conditions differ from that of tensile load conditions. For mixed-mode conditions, the intensity of singularity must be calculated for all singularity terms. In addition, the stress singularity characteristics at the vertex may be described as a function of the singularities along the singular lines. These findings clarify the understanding of singularity at interface corners of piezoelectric-brass unimorphs and may be used as references for developing relevant piezoelectric devices.

Generally, the major problems of moisture damage are caused by wetting, and particularly in construction, which has led to extensive research for the production of hydrophobic (anti-wetting) coatings. The aim of this research is to prepare an anti-wetting (hydrophobic) nanocomposite coating for different construction surfaces (ceramic, brick and gypsum). Hydrophobic nanocomposite coating was synthesized using electrospinning technique. Polymethyl methacrylate and polystyrene (PS) solutions were prepared in different ratios and then separately reinforced with ZrO 2 and ZnO nanoparticles. Contact angle, surface roughness, surface free energy and weathering effects were calculated for all specimens after being coated. All previously selected materials surfaces showed superhydrophobic and hydrophobic properties. The best results were obtained on ceramic surfaces after coating with PS/ZrO 2 . The water contact angle was 153° while the surface roughness was 0.491 µm and also showed the lowest surface free energy which was 5.5 mJ/m 2 . Weathering conditions tend to decrease the values of contact angle and this is due to the environmental effect of the weathering but they still have their hydrophobic properties. SEM test was used to determine the surface morphology and nanoparticle size for ceramic surfaces coated with PS and nano-ZrO 2 .

Cold spray process (CSP) is a thermal spray technology in which coating (10–40 µm) is formed in the solid state by the impingement of power particles with supersonic velocity (200–1,200 m/s 2 ) on coupon employing compressed gas jet, below the melting point of coating powder. It is commonly referred as cold gas dynamic spray, high velocity powder deposition, kinetic spray and kinetic energy metallisation process. Using CSP, various engineering materials (metals, polymers and ceramics) and its composites can be deposited. It is unique and promising approach for obtaining surface coating and offers various technological benefits over thermal spray as kinetic energy is employed for deposition rather than thermal energy. This offers great benefits in additive manufacturing (AM) to develop a component denser, low oxide coating free of tensile residual stresses, and undesired chemical reactions compared to conventional AM and coating techniques. Cold spray additive manufacturing (CSAM) is the powerful and emerging technique in the field of AM to develop engineering components with improved performance covering broad range of functionalities of surface, subsurface and interfaces. There are few flaws in this technique; however, extensive research work is going in CSAM and repairing of components to meet the real-time applications. The main objective of this review article is to summarise the history, effect of process parameters on surface coating, research and development in CSP along with its implementation in AM, component repairing and biomedical, antimicrobial and electrical applications. A discussion on future trends in CSAM is also provided at the end part of this article.

Risk management is important for project success as risks in petroleum projects must be minimized to achieve the goals of production. Risk management composes of planning, identification, analysis, and response, which is an important phase. Controlling risks gains the projects the capability to overcome the uncertainty and thus effectively produce the targeted quantities. In this study, four types of risks have been examined in the oil field, and the Iraqi oil exploration company has been taken as a case study. These four types of risks are operational, financial and administrative, economic and political, and potential risks. The effect of these types has been examined by using a closed-type questionnaire form. The questionnaire form was based on the Likert quintet scale, and it contains 114 risk factors distributed in four groups representing the examined four types of risks. Over 170 questionnaire forms have been distributed in the oil field to engineers, managers, experts, and technicians, and 153 forms have been adopted for the analysis. SPSS software was used to execute the statistical analysis concerning statistical mean and relative important index. The most important factors have been found and then validated by using an assessment checklist. It was found that the most factors affecting operational risks are as follows: the presence of mines and explosives left over from past wars in areas to be explored and the incorrect storage of flammable materials. Regarding the financial and administrative risks, it was found that the existence of financial and administrative corruption in oil companies and the mismanagement by managers or their assistants have the most effect on this type of risk. For the economic and political risks, it was found that the most important factors are the entry of some companies into the blacklist of major economic countries and decreased global market demand for oil. Finally, regarding the potential risks, it was found that the control of terrorist groups over the oil areas and regions is the most significant risk that the Iraqi oil and gas sector may face. In addition, it was concluded that the spread of Coronavirus disease 2019 and other epidemics should be treated as a potential risk because it has a huge effect on global oil prices.

Fire is one of the most critical risks devastating to human life and property. Therefore, humans make different efforts to deal with fire hazards. Many techniques have been developed to assess fire safety risks. One of these methods is to predict the outbreak of a fire in buildings, and although it is hard to predict when a fire will start, it is critical to do so to safeguard human life and property. This research deals with evaluating the safety risks of the existing building in the city of Samawah/Iraq and determining the appropriateness of these buildings in terms of safety from fire hazards. Twelve parameters are certified based on the National Fire Protection Association (NFPA2016) code. The concept of giving weight to each criterion was adopted to classify the criteria according to their importance and then conduct an on-site examination of these existing buildings to test the selected criteria. The result indicates a possible fire risk in these buildings due to the lack of compliance with fire safety instructions in the approved codes.

This study presents the findings of a 3D finite element modeling on the performance of a single pile under various slenderness ratios (25, 50, 75, 100). These percentages were assigned to cover the most commonly configuration used in such kind of piles. The effect of the soil condition (dry and saturated) on the pile response was also investigated. The pile was modeled as a linear elastic, the surrounded dry soil layers were simulated by adopting a modified Mohr-Coulomb model, and the saturated soil layers were simulated by the modified UBCSAND model. The soil-pile interaction was represented by interface elements with a reduction factor (R) of 0.6 in the loose sand layer and 0.7 in the dense sand layer. The study was compared with the findings of 1g shaking table tests which were performed with a slenderness ratio of 25. In the validation case, there was a clear correlation between the laboratory findings and the numerical analyses. It was observed that the failure mechanism is influenced by the soil condition and the slenderness ratio to some extent. Under the dry soil condition, no base pile deformation was observed; However, tip pile movement was observed under the saturated soil condition with pile slenderness ratios of 25 and 50. The findings of this study are also aimed to include an approximation of the long-term deformations at the ground surface which has experienced shaking.

In this experimental and numerical analysis, three varieties of under-reamed piles comprising one bulb were used. The location of the bulb changes from pile to pile, as it is found at the bottom, center, and top of the pile, respectively. PLAXES 3D was used to conduct the research. In expansive soil, the under-reamed piles were 350 mm long, with the pile tip in dense sandy soil. The experiment was carried out in both saturated and unsaturated circumstances. The influence of the bulb location on the pile's bearing capacity for vertical and lateral loads, as well as the amount of swelling pressure and upward movement owing to swelling, was investigated. The results showed that in the unsaturated state, the bulb at the top of the pile gives bearing that is higher than the bulb at the bottom of the pile and near to the bulb in the center. In the case of unsaturated soil, the closer the bulb is to the top, the larger the bearing capacity, whereas in the event of swelling, the bearing capacity is highest when the bulb is in the middle of the pile. The same is true of the pile's upward movement, which is greater when the bulb is at the top than when it is at the bottom.

Public procurement in Iraq plays an essential function in the development and recovery of the country's economy as well as providing the essential infrastructure for the growth of the private sector. The Coalition Provisional Authority's Government Procurement Legislation No. 87 (2004) is the final procurement law in effect in Iraq. Preparations are underway for new procurement legislation as of Oct. 2021. The objective of the paper is to determine the effectiveness of the public procurement process used in a construction project in Iraq, there is also a lack of procurement methods and policy consistency between government agencies. procurement techniques, tender documentation information, Advertising deadlines, and document management procedures, for example, vary amongst federal contracting agencies. Furthermore, there is no mandatory process for the definition and disclosure of tender evaluation criteria, providing room for subjectivity in the tender award process. This paper's major conclusion that is competitive tendering is open to everyone, tendering is not mandated as Iraq's general rule, despite the fact that it is considered best practice elsewhere. Direct invitation techniques are widely used in the construction project process tendering of Iraq and if not adequately managed, they can lead to bias, fraud, and corruption.

This work presents experimental research using draped prestressed steel strands to improve the load-carrying capacity of prestressed concrete non-prismatic beams with multiple openings of various designs. The short-term deflection of non-prismatic prestressed concrete beams (NPCBs) flexural members under static loading were used to evaluate this improvement. Six simply supported (NPCBs) beams, five beams with openings, and one solid specimen used as a reference beam were all tested as part of the experiment. All of the beams were subjected to a monotonic midpoint load test. The configuration of the opening (quadrilateral or circular), as well as the depth of the chords, were the variables studied in this study. In comparison to a solid beam, experimental results show that beams with openings have a lower load-carrying capacity not exceeding (2.3–10.6%) and higher mid-span deflection through all loading stages of elastic, service, and ultimate loads (14–73%), (19–44%), and (31–55%), respectively. Furthermore, specimens with circular openings had stiffer behaviour under load than those with quadrilateral openings. Beams with quadrilateral openings and inclined posts, on the other hand, were stiffer than beams with quadrilateral openings and vertical posts.

This study aims to investigate the adequacy of composite cellular beams with lightweight reinforced concrete deck slab as a structural unit for harmonic loaded buildings. The experimental program involved three fixed-ends supported beams throughout 2140 mm. Three concrete types were included: Normal Weight Concrete (NWC), Lightweight Aggregate Concrete (LWAC), and Lightweight Fiber Reinforced Aggregate Concrete (LWACF). The considered frequencies were (5, 10, 15, 20, 25, and 30) Hz. It was indicated that the harmonic load caused a significant influence on LWAC response (64% greater than NWC) and lattice cracks were observed, especially at 30 Hz. As for LWACF slab, no cracks appeared, and the harmonic load had a minor effect on the vibration amplitude. Adding fiber to LWAC improved its behavior and made the amplitude no more than 11.11%, corresponding to NWC. So, the response variance for the LWACF was approximately negligible compared with NWC. It is worth mentioning that the study produced a lightweight structure that resists harmonic vibrations with a small strength reduction by using LWACF as a deck-slab for cellular specimens and provides a structural element with a smaller density of about 27%, which presents an advantage for the cellular beam that is adopted for low-loaded structures.

Slurry infiltrated fibrous concrete (SIFCON) is a modern type of fibre reinforced concrete (FRC). It has unique properties; SIFCON is superior in compressive strength, flexural strength, tensile strength, impact resistance, energy absorption and ductility. Because of this superiority in these characteristics, SIFCON was qualified for applications of special structures, which require resisting sudden dynamic loads such as explosions and earthquakes. The main aim of this investigation is to determine the effect of fibre type on the apparent density of SIFCON and on performance under impact load. In this investigation, hook-end steel fibre and polyolefin fibre were used. Purely once and hybrid in different portions again. After reviewing previous research, including [1, 2, 3] references three trail mixes were tested with a volume fraction of fibres (4, 6 and 8)%, and after testing them, a volume fraction of 6% was chosen. We chose the volume fraction of 6% and made the type of fibre the variable for comparison in this research. In hybrid fibres this fraction was divided once 2/3 steel fibres with 1/3 polyolefin fibres and vice versa. The specimens of the Impact resistance test were made with two specimens for each series, which are panels with dimensions of 50×50×5 cm. Three cubes were made for each series in the SIFCON apparent density test. Test results prove SIFCON produced from 2/3 polyolefin and 1/3 steel fibres achieved a good density reduction that contributes to reducing the self-weight of the structural element, which is a major aim in this investigation, reducing cost and maintaining high impact resistance.

Microbial induced calcite precipitation method MICP is a sustainable and eco-friendly technique for soil stabilization. To show the optimum effectiveness of the bioremediation within the silty sand matrix, a model of plastic boxes and PVC molds was made with an air pump placed in an isolated room at a temperature range of 25–27°C. The molds were perforated from sides and bottoms and opened from the top with a transparent film of filter paper (placed on the inner surface). The major feature of this treatment system is allowing the cementation solution to penetrate easily into soil samples. The results showed a positive effect of Bacillus subtilis in enhancing the strength properties of lead contaminated soil. Unconfined compressive strength increased from 65 kPa to 539, 527, and 525 kPa. Cohesion increased from 4.5 to 40, 41.9, and 42 kPa at concentrations of 15, 20, and 25% respectively. Angle of internal friction increased from 18.94° to 38.2°, 40°, and 40.74° respectively after 14 days. Thereafter, it become 40.92° and 41.5° at concentrations of 15 and 20%, respectively and decreased to 36.75° of 25% at 28 days. Microstructural characteristics represent the formation of calcium carbonate and lead compounds, which were the reasons for the improvement in the strength and the alteration in lead from a soluble to insoluble form, a hence less toxic element.

Slurry-infiltrated fibrous concrete (SIFCON) is a special type of concrete that has great strength, as well as high ductility. However, the unit weight is high, which exceeds the unit weight of fiber-reinforced concrete, because of the high fiber content. This research aims to verify the compressive and flexural strength, as well as the density of SIFCON when using two different fibers (steel and polyolefin). Sometimes mono type of fiber steel or polyolefin, sometimes by hybridizing two types of fiber steel + polyplefin. Volume fraction (6% for all species) was used. Hook-end steel fiber and polyolefin fiber are used. With hybridization, a total volume fraction of 6% was used, which is 2/3 steel fibers with 1/3 polyolefin and vice versa. In addition, silica fume replaced 10% of the weight of cement. After checking all the results, the highest compressive strength was achieved in the SNS (symbol of mix SIFCON with 6% steel fiber) series by 81 MPa, as well as the highest flexural strength by 23 MPa, but it was the highest density of 2,490 kg/m 3 . The series contained 2/3 polyolefin and 1/3 steel fibers, which are ideal as they significantly reduced the density of the steel fiber series 2,490–2,210 kg/m 3 , as well as there was no significant reduction in strength as it achieved 67 MPa in the compressive strength and 19 MPa in the flexural strength, which are values suitable for high SIFCON applications.

Design of asphalt mixes and quality testing is influenced by the laboratory compaction procedure. Laboratory specimens must be manufactured in a way that suitably resembles field compaction for a performance test to give reliable mechanical properties. The internal structure of the mixture, which is referred to in this article as the spread of aggregate and air voids, provides the basis for the simulation. Gyratory compaction uses a kneading effort to produce cylindrical specimens. The goal of the present article is to determine the required strength for asphalt mix compaction of 40–50 per surface. This look was achieved with three distinct types of filler material and two kinds of sand. The asphalt mixture’s compressibility was tested. By adding the cumulative energy expended during gyratory specimen compaction to the compression data, the force applied to the sample during gyrations may be calculated. The relation between the number of gyrations and forces demonstrates pressure resistance. The measured fore force vs number of gyrations for combinations containing limestone, cement, and fly ash as fill materials was presented. The force required to compact the six bituminous materials was found to be influenced by the filler content. As the number of gyrations increases, its compaction properties change until it achieves a steady state. Except for the asphalt–cement mixture, compaction strength in mixes containing river sand requires less strength than compaction strength in mixes containing crushed sand.

The goal of this research is to develop a numerical model that can be used to simulate the sedimentation process under two scenarios: first, the flocculation unit is on duty, and second, the flocculation unit is out of commission. The general equation of flow and sediment transport were solved using the finite difference method, then coded using Matlab software. The result of this study was: the difference in removal efficiency between the coded model and operational model for each particle size dataset was very close, with a difference value of +3.01%, indicating that the model can be used to predict the removal efficiency of a rectangular sedimentation basin. The study also revealed that the critical particle size was 0.01 mm, which means that most particles with diameters larger than 0.01 mm settled due to physical force, while most particles with diameters smaller than 0.01 mm settled due to flocculation process. At 10 m from the inlet zone, the removal efficiency was more than 60% of the total removal rate, indicating that increasing basin length is not a cost-effective way to improve removal efficiency. The influence of the flocculation process appears at particle sizes smaller than 0.01 mm, which is a small percentage (10%) of sieve analysis test. When the percentage reaches 20%, the difference in accumulative removal efficiency rises from +3.57% to 11.1% at the AL-Muthana sedimentation unit.

This study is a numerical investigation of the performance of reinforced concrete (RC) columns after fire exposure. This study aims to investigate the effect of introducing lateral ties and using the RC jacket on improving post-fire behavior of these columns, the effect of the duration of the fire on ultimate load of columns. The analysis was performed through ABAQUS, a 3D – non-linear finite element program. 4 m tall lengthening square RC column with a cross- section of 0.4 m × 0.4 m was used as a test specimen. The RC column was reinforced by 4Ø28 mm longitudinal bars bonded by steel tie bars of Ø10 mm spaced at 400 mm. The firing temperature was increased to 600°C for 60 min. The results indicated that as the fire load duration increases, the load’s capacity diminishes. The effect of increasing the steel ratio of the RC column resulted in a decrease in the percentage of load reduction following combustion. It was concluded that strengthening columns by RC jackets is efficient and that the axial load capacity of reinforced columns was enhanced.

The effect of magnetization of saline irrigation water from Almasab Alam on some soil physical properties was investigated in this study. The soil was taken from the study site and placed in pots that were identical in all aspects and planted with onion plants in three replications for each case, with the average results taken. The only difference is the quality of the water used in irrigation, which was tested in seven different ways, including irrigating with Almasab Alam drainage salty water without magnetization (NMW), irrigating with river water (CW) from the Mashroa Almusyyab Al-Kabeer river, and irrigating with magnetized Almasab Alam water with five different magnetic intensities (1,000, 2,000, 3,000, 5,000, and 7,000  gauss). When magnetized water with a strength of 3,000 gauss is used, the highest decrease in the bulk density of the soil is 27.30%, and the highest increase in the porosity and permeability of the soil is 64.52 and 651.54%, respectively. Using magnetic technology has made saline Almasab Alam water and drainage water suitable for irrigating crops and also overcome the study area’s water scarcity. Using the magnetic technique of irrigation water also improved the physical properties of the soil, including density, porosity, and permeability, in the study area by washing or planting it with crops.

Environmental sustainability is described as one that avoids the depletion or deterioration of natural resources, while also allowing for the preservation of long-term environmental quality. By practicing environmental sustainability, we may assist to guarantee that the requirements of today’s population are satisfied without risking the capacity of future generations to meet their own needs in the future. Engineers in the field of concrete production are becoming increasingly interested in sustainable development, which includes the utilization of the locally available materials in addition to using the agricultural and industrial waste in construction industry as one of the possible solutions to the environmental and economic issues. This study investigated the effect of partial substitution of cement with recycled glass powder (0, 15, 20, and 25%) by weight of cement at various ages (on compressive strength) after determining the optimal ratio of replacement. This optimal ratio is used to study its effect on some mechanical properties (such as flexural strength, absorption, and dry density) of reactive powder concrete containing 1% micro steel fiber (SRPC), and furthermore, utilizing steam curing for 5 h at 90°C after hardening the sample directly. Reactive powder concrete (RPC) has been designed with the use of the local cement, silica fume, and super plasticizer with a water/cement ratio of 0.20 in order to achieve a compressive strength of 137.09 MPa at the age of 28 days. When recycled glass powder replacement (20%) was utilized, the findings revealed that the compressive strength of RPC improved by 4.2%, the flexural strength increased by 15.3%, the dry density increased by 0.61%, and the absorption was reduced by 32% at 28 days after the test results were compared to the reference mix.

Different injection material types were tried in the injection of soft clay, such as lime (L), silica fume (SF), and leycobond-h (LH). In this study, experiments were made to study the effect of injection on soft clay consolidation settlement. A sample of natural soft clayey soil was investigated in the laboratory and the sample was injected with each of the grout materials used, L, SF, L + SF, and L + SF + LH. A 20 cm 3 of each slurry grout was conducted into the soil, which was compacted in California Bearing Ratio (CBR) mold and cured for 7 days, and then the sample was loaded to 80 N load by a circular steel footing 60 mm in diameter. The settlement was recorded. The sample of each slurry grout, which provided minimum settlement, was chosen (L + SF + LH). To reduce soft clay settlement before and after footing construction, four cases were investigated. The impact of injection hole spacing and grout depth was studied. It was discovered that injecting a slurry of (L + SF + LH) into the soft clay beneath or surrounding the footing increased bearing capacity by 5–88%. Due to the shape of shear failure of the soft clay around the footing, grouting near the footing at a distance of 0.5 diameter of the footing is more effective than grouting at a distance of 1.0 diameter of the footing, and grouting near the footing at a distance of 0.5 diameter of the footing is more effective than grouting at a distance of 1.0 diameter of the footing.

With the spread of the use of liquefied petroleum gas (LPG) in developing countries for use in domestic cooking with the increase in the expansion and distribution of gas pipelines for residential buildings, the 2002 World Summit focused on sustainable development in clean energy for natural gas (NG) and LPG. The research aims to focus on the important aspects of design sustainability from an environmental point of view to reduce gas leakage, accidents, and explosions that occur socially to expand the distribution of LPG and motivate the consumers to use it instead of natural gas and other fuels, and from an economic point of view to take into account the annual cost and aesthetic impact of maintaining on the view of the building and the design of the pipes in ways that do not distort the public view. The study area was a building in a residential complex in Baghdad and the gas pipelines were connected to the building completely for studying. The axes of sustainability were applied to the building in an analysis method using the goals achievement matrix, which is divided into main goals and secondary goals. The results showed that the environmental and aesthetic sustainability were well applied to the building, but from a social point of view, in the dissemination of safety instructions to the consumer, and from a financial point of view, there were shortcomings in them, and this could lead to long-term damage to the building.

Serial tendering is better than other types of tendering when it comes to cost reduction, where civil infrastructure projects need a significant increase in the amount of tough planning, financial expenditures, engineering work, and resources of a different character than other types of construction projects. The effects of a lack of funding cause decrease in the completion speed of the project on time. The need to reduce the cost of bidding on recurrent civil infrastructure projects is critical. To achieve the desired goals of this research, this article will provide an overview of the type of bids used in the construction of schools implemented in the current financial perspective in Iraq, the extent of benefit, and the amount of possible reduction if continuous and serial tendering are used.

Construction contractors usually undertake multiple construction projects simultaneously. Such a situation involves sharing different types of resources, including monetary, equipment, and manpower, which may become a major challenge in many cases. In this study, the financial aspects of working on multiple projects at a time are addressed and investigated. The study considers dealing with financial shortages by proposing a multi-project scheduling optimization model for profit maximization, while minimizing the total project duration. Optimization genetic algorithm and finance-based scheduling are used to produce feasible schedules that balance the finance of activities at any time with the available funds. The model has been tested in multi scenarios, and the results are analyzed. The results show that negative cash flow is minimized from −693,784 to −634,514 in enterprise I and from −2,646,408 to −2,529,324 in enterprise II in the first scenario and also results show that negative cash flow is minimized to −612,768 with a profit of +200,116 in enterprise I and to −2,597,290 with a profit of +1,537,632 in enterprise II in the second scenario.

Many risks have adverse consequences for construction projects’ objectives such as quality, schedule, and cost. As engineering procurement construction (EPC) contracts gradually become one of the most common types used in implementing major large-scale construction projects, identifying common risk types and analyzing their root causes is important for developing measures to decrease and eliminate future risks in these types of contracts. The information about the main causes of risks was collected via well-structured questionnaires addressed to construction sector professionals and preparing lists of main potential risks in EPC/construction projects through reviewing literature studies, books, and articles related to this topic. The findings indicate that several causes of risks are more critical for the project including causes related to contract, design and execution, subcontractors, systems, and equipment. The study’s results revealed that the absence of risk management implementation in the EPC construction project is a root cause of the lack of planning and control of the project.

The quality and cost of constructed buildings are heavily influenced by the performance of design/auditing consultants. Thus, selecting the right design consultant and design auditing consultants is of utmost importance and not an easy task for any construction client. so, the client should specify the efficiency criteria and assess the performance levels of the design and design auditing consultant firm. The study aims to identify the selection criteria of the design consultant in construction projects and also identify the selection criteria of the design auditing consultant for the construction projects by using the Delphi survey with applying the principal components analysis (PCA). The results of the present study showed that there are 13 key criteria for selecting the design consultant, where the criterion of “Efficiency and experience of the company/consultant in previous work” was of the highest importance. While there are Ten key criteria for selecting the design auditing consultant for the construction project, where the criterion of “Credibility and professional integrity (transparency, professional conduct, and ethics)” was of the highest importance in the decision-making process. Moreover, the results of applying PCA on the Delphi survey outcomes showed that all the resulting selection criteria are most valuable and suitable for the selection process in construction projects.

Water supply and distribution networks play an important role in our daily activities. They make a substantial contribution to public health by providing potable water for public consumption and non-potable applications such as firefighters and other purposes such as irrigation. This study used ArcMap 10.8 and WaterGEMS CONNECT Edition update 1 version to create a hydraulic network model to simulate the pipes’ network. Detailed network information, including pipe lengths, layouts, and diameters, was given by the Baghdad Water Department. The TUF-2000H Handheld digital ultrasonic flow meter has been used to measure the water flows in the network’s source nodes. In eight junctions, the model was calibrated by measuring the pressures using the Bourdon gauge at selected junctions. The analysis was based on the steady-state time at the average demand. The analysis results showed that the pressures in the network ranged from 8 to 21 m H 2 O with a correlation coefficient of 0.988, with a noticeable decrease in pressures in the distant pipes from the sources supplying water to the network. The velocity of the main pipes was within acceptable limits 0.5–2 m/s. While for the internal distribution network, it was noticed that there is an increase in velocity for the main pipes due to low consumption in the lateral pipes.

Gypseous soil is a metastable soil that causes problems in the constructions built on it under wetting conditions. Due to the harmful effects of traditional soil binders such as lime or cement on the environment, alternative environmental-friendly materials have been used to decrease this impact. Casein biopolymer is introduced in this study as a new binder for gypseous soil improvement and milk waste minimizing purposes. The study focused on three primary soil features: compaction properties, shear strength, and collapse potential. These three soil properties are important in the ground improvement techniques. In this study, different casein concentrations were added to the soil with varying gypsum contents. According to the compaction results casein reduces the maximum dry density while increasing the optimum moisture content. Soil treated with casein had a collapse potential of 65–80% lower than untreated soil. The shear strength of casein-treated soil increased significantly in both dry and moist conditions. The current study results suggest the recycled casein as an eco-friendly additive for gypseous soil treatment rather than traditional chemical materials.

Few studies have been conducted on the structural behavior of steel columns with branches that are called tree-like columns. These kinds of columns have been used in many structures around the world. The purpose of this study is to investigate the failure load, vertical and lateral displacement, and failure mode of tree-like columns subjected to a combination of axial and lateral loading. The ratio of lateral load to axial load has been selected as the design variable. A finite element model with one branching level and two branches within the level was first developed using ABAQUS/CAE 2017 software. The model was verified with experimental results. The axial failure load and axial and lateral displacement were determined and compared for different loading ratios. The failure mode was also studied for different loading conditions. The results showed that the axial failure load decreased significantly by 54, 42, and 28% when lateral/axial loading ratio increased by 20, 40, and 60%, respectively. There was no significant decrease when lateral/axial loading ratio was more than 60%, while axial and lateral displacements increased significantly by 24% for each 20% increase in the loading ratio. Local buckling was observed as a failure mode when only gravity load is applied, while combined load resulted in lateral buckling.

Geotextile reinforcement techniques have been widely used in paving works around the world and have proven to be effective in improving pavement performance. This study has focused on using different positions and numbers of geotextile reinforcement sheets between the layers of flexible pavement for rutting reduction. Fitting depth was measured in the field at seven constructed sections of the pavement of the road model. Each section has been strengthened with different reinforcement approaches. All road sections were subjected to a maximum load repetition of 10,000 cycles. The results indicate that using three layers of geotextile beneath each course of the designed road pavement sections (surface, binder, and base) reduced rutting by 96%. Traffic benefit ratio (TBR) has been employed in this study to reveal the behavior of geotextile reinforcement in increasing the service life of the road. TBR values are the load cycling ratio between the reinforced and unreinforced section for the exact recorded rut depth, it has been found to be minimally equal to 4 for the case of using one layer of reinforcement at interface I, and that value keeps growing up for other reinforcement cases.

Construction of shallow foundations on weak cohesive soils have limited load-bearing capacity and excessive vertical displacement. This may cause structural damage and reduce the structure’s durability. Traditionally, weak cohesive soils are excavated and replaced with another stronger material layer, or the foundation is enlarged. These procedures are costly and time-consuming. However, these soils are also difficult to stabilize due to their low permeability and slow consolidation. Therefore, it has become necessary to use geosynthetic material. In this study, a square footing model with an eccentric load was tested in geogrid-reinforced clay. The adopted load eccentricity ratios were 0.05 to 0.1, 0.16, and 0.25. Twenty-one tests were executed to estimate the reinforcement influence and eccentricity on the ultimate bearing capacity (UBC). The geogrid improved the BC by 2.27 and 2.12 times compared to unreinforced soil for centrical and eccentrical loads, respectively. The best first layer ratio and the best number of reinforcements were found to be 0.35 and 4. A new equation for BCR with knowing the number of reinforcing layers was proposed and compared with other studies’ outcomes. It was concluded that the foundation tilts in a linear relationship with eccentricity, with a smaller rate inside the core than outside.

This research investigated the influence of water-absorbent polymer balls (WAPB) on reinforced concrete beams’ structural behavior experimentally. Four self-compacted reinforced concrete beams of identical geometric layouts 150 mm × 200 mm × 1,500 mm, reinforcement details, and compressive strength f c ′ {f}_{\text{c}}^{^{\prime} } ≈ 50 MPa were castellated. Each beam contained a volume percentage of WAPB that differed from the others, and the considered percentages were V b = 0, 1, 2, and 3%. A static test under two-point loads was adopted to evaluate the structural behavior of the tested beams. The results indicated that the maximum load capacity of the tested beams was increased by 2.0, 3.0, and 7.14% for the volume percentages of 1, 2, and 3%, respectively, as compared to the reference beam ( V b = 0%). It was also observed that the impact of V b = 3% was higher than that of the other percentages. For all the tested beams, the mode of failure was a flexural failure that is compatible with the considered preliminary design. The results showed that increasing the percentage of polymer to 3% had a significant effect on the deflection, as the deflection was directly proportioned to the percentage of WAPB.

Measurement of construction performance is essential to a clear image of the present situation. This monitoring by the management team is necessary to identify locations where performance is exceptionally excellent or poor and to identify the primary reasons so that the lessons gained may be exported to the firm and its progress strengthened. This research attempts to construct an integrated mathematical model utilizing one of the recent methodologies for dealing with the fuzzy representation of experts’ knowledge and judgment considering hesitancy called spherical fuzzy analytic hierarchy process (SFAHP) method to assess the contractor’s performance per the project performance parameters (cost, schedule, quality, leadership, and change management). At the same time, most project control systems are currently applied through software like Primavera P6 or MS Project. These look at a project’s cost and schedule status by following the earned value analysis for finding the performance. Based on decision makers’ preferences, the analytic hierarchy process (AHP) may be used to arrive at the optimum conclusion. AHP approaches are discussed, including AHP, grey-AHP, fuzzy-AHP, and SFAHP weights comparison. Calculation results showed that the spherical fuzzy approach differs significantly from the other approaches where it considers the decision maker’s hesitation when making linguistic multicriteria decisions and then, as a result, recommends applying periodically for performance measurement. This model can be viewed as a valuable way to help the decision-making stakeholders in the construction sector do the best job about critical issues at a suitable time.

This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several number of openings (six and eight) and posts’ inclination, aimed to find the strength reduction in this type of beam. The major results found are: for the openings extending over similar beam length it is better to increase the number of posts (openings), i.e. , increasing opening number led to decrease in opening area, which allows us to transmit stresses and act as lever arms between the upper and the lower chords. Also, findings revealed that the inclined posts have larger loading at the mid-point relative to vertical ones. For gables with vertical posts having six and eight openings, the ultimate strength reduction was 31.5 and 25.6%, whereas it was 29 and 17.3% for those with inclined posts, respectively.

The Great Mosque of Kufa, built in 639 CE and located in Al-Kufa, Iraq, is considered one of the most important mosques in the Islamic world. Because cracks appeared in the historical walls of the Al-Kufa Mosque during the construction of the Muslim Bin Aqeel Underpass, the values and locations of bending moment and shear force may be useful for wall maintenance. So, this study aims to determine the maximum and minimum values and locations of settlement, bending moment, and shear forces under the mosque walls’ foundations. Historical references are used to know the previous architectures of the mosque. Also, archaeological investigation reports are adopted to find out the characteristics of the foundations like their dimensions, depths, and materials. Soil investigation reports are used to know the soil layer’s properties and parameters. For non-mentioned soil parameters in soil investigation reports, they are determined depending on the theoretical equations, charts, statistical correlations, and models. A model of soil layers, foundations, and walls is conducted and analyzed using finite element software to determine the deformations of soil layers under the mosque’s brick foundations and walls. According to the analysis, maximum bending moment and shear force were found under the minaret near the Al-Thuaban gate.

This study conducted an analytical investigation on the behavior of concrete beams with openings reinforced by glass-fiber-reinforced polymer (GFRP) bars. In this study, five proposed beams reinforced by GFRP bars as flexural and shear reinforcement with openings were numerically examined. The variables were the opening orientation (vertical and horizontal) and the number of openings. These openings were located within the flexural zone of the proposed beams. The result shows that the vertical openings had a significant effect over the horizontal openings on reducing the ultimate load and increasing the mid-span deflection compared with the control beam. Moreover, the results showed that when replacing two adjacent openings by one equivalent opening, the capacity of the beam is decreased.

Using the ABAQUS software, this article presents a numerical investigation on the effects of various stud distributions on the behavior of composite beams. A total of 24 continuous 2-span composite beam samples with a span length of 1 m were examined (concrete slab at the top and steel I-section at the bottom). The concrete slab used is made of a reactive powder concrete with a compressive strength of 100.29 MPa. The total depth of each sample was 0.220 m. The samples were separated into four groups. The first group involved 6 specimens with shear connectors distributed into 2 rows with different distances (65, 85, 105, 150, 200, and 250 mm). The second group had the same spacing of shear connectors as the first group except that the shear connectors were distributed with one row along the longitudinal axis. The third group consisted of six specimens with single and double shear connectors distributed along the longitudinal axis. The fourth group included six specimens with one row of shear connectors arranged in a staggered distribution along the longitudinal axis. Results show that the optimum spacing was 105 mm in all groups and the deflection in group four fluctuated up and down due to the non-symmetrical distribution of the shear connectors.

This research aims to investigate the applicability and performance of piled rafts in soft clay. This aim has been achieved by studying how the pile length, pile number, raft-soil relative stiffness, and presence of a sand cushion beneath the raft would affect piled raft settlement, differential settlement, and load sharing. Piled rafts have been numerically simulated using PLAXIS 3D software. Experimental testing results were used to verify the numerical simulation. The portion of the load carried by the piles to the total applied load was represented by the load sharing ratio (GPR). The results indicated that with increasing pile length and number, settlement and differential settlement decreased. It was also noticed that with increasing raft-soil relative stiffness, the differential settlement decreased. The GPR decreased with increasing thickness and relative density of the sand cushion, whereas it increased with increasing pile length and number. This increase in GPR was 13.7, 36, and 58% with an increase in pile length to diameter ratio from 10 to 30 for the number of piles 4, 9, and 16, respectively. Additionally, the raft-soil relative stiffness was observed to have a marginal effect on the GPR.

The Ministry of Electricity (MoE) is one of Iraq’s most significant sectoral ministries. Despite massive amount invested in power generation, the country is plagued by power outages for more than three decades. One of the most common sources of the problem and significant impact on the waste of public funds in contractual processes. The Ministry of Planning issued regulations and procedures to facilitate the implementation of power plants by applying the sectorial standard bidding documents (SSBD) of design, supply, and installation of the electromechanical project to support MoE by developing economic projects that lead to raising Iraqi electricity generation field. The research evaluates the government evaluation procedures applied in SSBD and their impact on Iraqi power plant contracts. The study’s principal data gathering approaches via interviews with consultants resulted in a structured questionnaire that includes 25 criteria delivered to MoE’s senior staff. One hundred respondents out of 120. The relative importance index was applied to rank and match respondent consensus on the relevance of the 25 factors. This article’s primary conclusion is weak evaluation of SSBD criteria and inadequate bid evaluations, resulting in an ineffective procurement system, and the results aim to encourage MoE’s decision-makers to optimize the criteria.

This study was prepared to investigate the performance and behavior of concrete thrust blocks supporting pipe fittings. In the water distribution networks, it is always necessary to change the path of the pipes at different degrees or to create new branches. In these regions, an unbalanced force called the thrust force is generated. In order to counter this force, these regions are supported with concrete blocks. In this article, the system components (soil, pipe with its bend and thrust blocks) have been numerically modeled and simulated by the ABAQUS CAE/2019 software program in order to study the behavior and stability of the thrust block with different burial conditions (several burial depths) by the soil under the influence of the thrust force. Accordingly, 45° bend angles were studied with a specified pipe diameter placed on soil with known properties under the influence of internal hydrostatic test pressure. The obtained results that were relied upon to describe the behavior and stability of the block are (the lateral displacement of the block in the direction of the thrust force, as well as the vertical displacement of the block in addition to the Von Mises stresses transmitted by the block to the soil). It was concluded that the case in which the block is fully supported from its back side represents the optimum state of the block as it provides marginal sliding of the block and the least transmitted stress to the soil. It was also concluded that the transition from the first case (thrust block without soil behind it) to the second case (a quarter of the block is supported by soil), in which the maximum change in the performance of the concrete block was recorded, but after shifting to the other cases, the effect was reduced gradually.

Geopolymer (GP) has recently emerged as a novel and environmental friendly alternative to conventional soil stabilization products like lime and Ordinary Portland Cement (OPC), which adversely affect the environment. This article emphasizes GPs produced from high calcium class C fly ash (CFA) and an alkali activator comprising sodium hydroxide and sodium silicate solution for sand stabilization. The experimental program includes a series of unconfined compressive strength (UCS), flexural strength, tensile strength, and microstructural analyses using scanning electron microscopy. Results revealed that UCS, flexural strength, and tensile strength of GP-treated soil were in the range of 2–10, 0.5–2.0, and 0.4–1.2 MPa, respectively (depending on the ratio of fly ash and activator). These strengths were even higher than those of cement-stabilized soil. The microstructural analysis revealed that the formation of dense calcium–sodium alumina–silicate hydrated gel (C, N–A–S–H) is the reason for strength improvement. According to the findings of this study, using a CFA-GP binder for soil improvement is a viable alternative to OPC in geotechnical applications.

The identification and stratification of soils represent an essential step in designing various geotechnical structures. The cone penetration test (CPT) measurements are used widely to classify the soil; however, the soil classification charts such as the Robertson chart undergo uncertainty from different sources that make overlapping of soil types. This article aims to develop a probabilistic approach employing clustering with Gaussian mixture model, which can deal with the uncertainty and classify the soil based on CPT. The spatial parameters were obtained assuming the different types of covariance matrices. The data utilized in this study represent the results of CPT in four locations in Nasiriyah, Iraq. Both spatial and feature patterns were produced and used to classify the soil. This research revealed that the soils deduced from the Robertson chart were clay, silt, and sand. No gravelly sand appeared on the chart. The soil at shallow depth was clay soils, and it changed to be sandy silt at fairly great depth. They were close to the boundary curve between the stiff clay and sand zones and relatively existed at great depth. The probabilistic approach can detect the soil layers fast without experience-based decisions. Moreover, the type of assumed covariance matrix may affect the soil profile.

Gypseous soils are considered one of the most problematic soils. The skirted foundation is an alternative technology that works to improve the bearing capacity and reduce settlement. This paper investigates the use of square skirted foundations resting on gypseous soil subjected to concentric and eccentric vertical load with eccentricity values of 4, 8, and 17 mm in 16 experimental model tests. To obtain the results by using this type of foundation, a small-scale physical model was designed to obtain the load–settlement behavior of the square skirted foundation; the dimension of the square footing is 100 mm × 100 mm with 1 mm thickness, the skirt depth ( D s ) was 0.5, 1, and 1.5 B (where B is the footing width). The footing rests on dry gypseous soil with a relative density of 33%. The tests show that the gypsum content of the soil is 59%. The result shows that the highest bearing capacity for the square shape footing with D s / B = 1.5 subjected to concentric load results in an improvement ratio of 190%. For the eccentric load, with D s /B = 1.5, the increase in bearing capacity is about 120% at e = 8 mm when compared with using a foundation without a skirt.

The main objective of this work was to adopt an environmentally friendly technology with enhanced results. The technology of magnetic water (MW) treatment system can be used in concrete mixture production instead of potable water (PW) to improve both workability and strength. Two types of concrete were adopted: normal concreter production with two grades 25 and 35 MPa and the self-compacted concrete (SCC) with 35 MPa grade. The concrete mixes containing MW instead of PW results showed that, for 25 MPa grade, an improvement in a compressive strength of 15.1, 14.8, and 10.2% was achieved for 7, 28, and 90 days, respectively. For 35 MPa grade, an improvement of 13.6, 11.5, and 9.1% was achieved for 7, 28, and 90 days, respectively. The mixture of SCC showed the highest improvement up to 16.2, 15.8, and 12.4% for 7, 28, and 90 days, respectively. The effect of MW is significant for 7 days compared to 28 and 90 days. An increase in the water content to cementitious material presents the more efficiency of MW, while the combined effect of MW and superplasticizer in SCC showed the best improvement with less water content for 35 MPa grade.

Several research studies have been conducted on the usage of nanoscale silica particles in concrete, based on the success of employing silica fume as an active pozzolan in concrete. The impact of several doses of nanosilicas (NpSs) in powder having a certain surface area of 160 m 2 /g and two particle sizes of porcelanite rock on the mechanical characteristics of lightweight porcelanite aggregate concrete was investigated. The addition of NpS particles significantly improved the workability of mixes, according to the results. The compressive strength of samples was influenced by NpS, with higher doses of NpS resulting in greater improvement. Porcelanite aggregate concrete’s compressive strength was unaffected by a modest percentage of different NpSs. NpS had an effect on the samples. Flexural strength also improved at all NpS dosages. The flexural strength of porcelanite aggregate concrete increased by a low percentage of various NpS.

Many contractors face challenges in completing the project on time due to delays arising for various reasons, including reasons beyond the contractor’s control, such as force majeure, exceptionally bad weather conditions, changes, etc. As a result, contractors submit a time extension claim to make up for lost time and set a later completion date to complete the project. Each contract has its terms for the extension of time (EOT). Therefore, the objective of this article is to study the provisions for extending the time when the reasons are beyond the control of the contractor according to Iraqi Standard Bidding Documents for Procurement of Works (SBDW) and the Joint Contracts Tribunal (SBC/Q 2016). The article also aims to show the extent of the difference between the two contracts in applying these provisions. The study found that when submitting a claim in the Iraqi SBDW, the contractor shall consider the notifications relating to it as per the specified period. Therefore, they will not be considered if claims are submitted after that period. In SBC/Q 2016, submitting a claim notice is not required to gain additional time. Therefore, the failure to provide notice does not forfeit the right to claim additional time. This study enhances the contractor’s knowledge of the terms related to the EOT under the two contracts, reducing the disputes resulting from a misunderstanding of these provisions.

For the design of a deep foundation, piles are presumed to transfer the axial and lateral loads into the ground. However, the effects of the combined loads are generally ignored in engineering practice since there are uncertainties to the precise definition of soil–pile interactions. Hence, for technical discussions of the soil–pile interactions due to dynamic loads, a three-dimensional finite element model was developed to evaluate the soil pile performance based on the 1 g shaking table test. The static loads consisted of 50% of the allowable vertical pile capacity and 50% of the allowable lateral pile capacity. The dynamic loads were taken from the recorded data of the Kobe earthquake. The current numerical model takes into account the material non-linearity and the non-linearity of pile-to-surrounded soil contact surfaces. A lateral ground acceleration was adapted to simulate the seismic effects. This research emphasizes modeling the 1 g model by adapting MIDAS GTS NX software. This will, in turn, present the main findings from a single pile model under a combined static and dynamic load. Consequently, the main results were first validated and then used for further deep investigations. The numerical results predicted a slightly higher displacement in the horizontal and vertical directions than the 1 g shaking table. The shear stress–shear strain relationship was predicted. Positive frictional resistance for the closed-ended pile was captured during the first 5 s when low values of acceleration were applied and, consequently, the pile resistance decreased and became negative. Internal and external frictional resistance was captured for the open-ended pipe pile. Overall, frictional resistance values were decreased with time until they reached the last time step with a minimum value. As a result, the evaluation of the current study can be used as a guide for analysis and preliminary design in engineering practice.

Reactive powder concrete (RPC) is one of the distinctive kinds of concrete whose benefits are high mechanical performance and durability. It contains a high content of cement, which means a high amount of carbon dioxide emitted during manufacturing. Scientists have tended to search for a way to reduce environmental damage, and one solution is to partially replace cement with mineral admixtures, waste from other industries, or by-products. There are restricted studies involving the use of high content of compounding mineral admixtures in the making of RPC. Therefore, this research aims to produce sustainable RPC with a low cement content (50%). The main objective of this research is to study the impact of substituting cement with 50% of silica fume (SF) + fly ash (FA) on the mechanical characteristics of RPC. Three mixtures containing various percentages of SF + FA were poured, in addition to the reference mixture. Flowability, flexural and compressive strengths, ultrasonic pulse velocity (UPV), and density were examined. The results showed that a sustainable RPC can be produced by substituting the cement with 10% SF and 40% FA with an improvement in workability and compressive strength and an insignificant reduction in other properties.

Collapsible soils present significant geotechnical and structural engineering challenges worldwide. They can be found in arid or semi-arid regions and are directly affected by the multi-step wetting procedure due to the reduction of soil suction. The main objectives of this paper are to investigate the volume change behaviour, collapse mechanism and deformation characteristics under the control of suction and net vertical stress. In this study, three types of collapsible soils were investigated such as natural soils of sandy gypseous, silty loess, and artificial soil of gypsum–sand mixture. A series of constant net stress-suction control (wetting and drying) tests using a combination of axis-translation and vapor equilibrium techniques were deployed to cover a wide range of applied suction. The test results show that large volume change and collapse deformation occur upon a stepwise suction decrease. On the other hand, shrinkage behaviour resulting from increases in imposed suction is observed during the drying path. The collapse deformation depends on the stress path and is a function of net normal stress, suction, dry density, and degree of saturation. The water content and the degree of saturation dramatically increase as the applied suction decreases from the initial high to zero values at the drying path.

This study includes adding chemicals to gypseous soil to improve its collapse characteristics. The collapse behavior of gypseous soil brought from the north of Iraq (Salah El-Deen governorate) with a gypsum content of 59% was investigated using five types of additions (cement dust, powder sodium meta-silicate, powder activated carbon, sodium silicate solution, and granular activated carbon). The soil was mixed by weight with cement dust (10, 20, and 30%), powder sodium meta-silicate (6%), powder activated carbon (10%), sodium silicate solution (3, 6, and 9%), and granular activated carbon (5, 10, and 15%). The collapse potential is reduced by 86, 71, 43, 37, and 35% when 30% cement dust, 6% powder sodium meta-silicate, 10% powder activated carbon, 6% sodium silicate solution, and 10% granular activated carbon are used, respectively.

Earthquake-induced liquefaction is prone in a region with loosely saturated sand and higher seismic activity. In recent years, improvement techniques have been used as a pre-construction or retrofitting method for the current construction. Several methods are intended as remedial techniques, which include either densifying the deposit soil, inserting a unique material, or controlling dissipated pore water pressure generated during the seismic motion. The permeation grouting technique is primarily used in remedial liquefaction schemes that aim to improve the soil deposit mainly by cementing the soil particles and filling the void spaces, thereby preventing soil disturbance caused by settlements or distress to an existing foundation or structure. Permeation grouting involves the injection of a low viscosity chemical or particulate grout into the soil pores with little to no change in the soil structure and has been shown to be effective at reducing liquefaction risk beneath existing structures in soils where it is applicable. The mitigation of liquefaction risk by incorporating nanomaterials using the permeation grouting technique, to study the performance of a pile group embedded in the liquefiable treated layer with 1/50 nano-clay and 1/30 nano-SiO 2 after 48 h of curing time during the Kobe earthquake, has been adopted. The soil profile treated using nanomaterials showed that the soil stiffness and strength were preserved during shaking because it did not liquefy; simultaneously, the maximum pile bending moments and lateral pile displacements in the treated soil layer were reduced by 30%. Finally, after treatment, the nanomaterials have a significant effect on the reduction of the maximum accelerations in two depths of soil.

In this study, a sustainable filler made from papyrus fiber ash (PFA) is used as a partial cement replacement in hot mix asphalt mixtures (HMA). The replacement levels used are 0, 5, 10, and 15% by weight of ordinary Portland cement. The hot mix asphalt samples were subjected to Marshal volumetric properties (stability, flow, and air voids) and service tests (tensile strength ratio test and immersion compression test) to predict the influence of the used filler modifier on the moisture sensitivity of blended HMA. Best results have been achieved by using 10% of PFA, whereas all the prepared samples with the mentioned percentage of the filler modifier showed a lower sensitivity to moisture in comparison with the control samples, which contained 0% of PFA. The used technique proved to be very efficient in keeping the pavement safe from deformation caused by moisture. At the same time, using sustainable filler materials proved to be an environmentally eco-friendly method.

In this study, the possibility of producing colored geopolymer concrete consisting of slag as a binder and studying the effect of pigment on some properties of geopolymer concrete is discussed. Here two types of pigments (chromium oxide “green” and iron oxide hydroxide “yellow”) were added to the geopolymer concrete and some tests such as slump values, compressive strength, flexural strength, and permeability test were conducted. The results showed that the best percentage of pigment addition was 1% of the weight of the slag, and with increasing addition, the mechanical properties began to deteriorate.

In the presence of harsh economic conditions, conducting laboratory experiments in a wide anticipated area to determine soil properties for any purpose or task within a city is unachievable. Hence, this work is focused on incorporating the existing record data of 56 distinct soil samples acquired from different pits of Kirkuk city utilizing spatial analysis described by inverse distance weighted (IDW) and Kriging methodologies. The incorporated constituents were principally categorized into basic soil characteristics such as clay, silt, sand, and gravel contents and various soil parameters such as initial void ratio ( e o ), angle of internal friction ( ϕ ), cohesion ( c ), and optimum soil moisture content. Moreover, quantitative approaches such as geotechnical parameters association, linear single, and linear multi-regression models were used. Significant discrepancies in both approaches are readily obvious in the third to fifth zones, indicating that IDW and Kriging processes describe the distribution of sand in Kirkuk city differently. Furthermore, linear multi-regression model between basic and investigated soil parameters show good to excellent and very good to excellent degrees of correlation, with multiple R values in the range of (0.77–0.97) and (0.86–0.98), respectively.

This article presents the experimental investigations undertaken to evaluate the strengthening and enhancement characteristics of near-surface mounted (NSM) devices using different types of bars. A total of 4 concrete beams (150 mm × 300 mm × 1,500 mm) were reinforced in flexure. Three beams strengthened with different embedments of NSM (carbon fiber-reinforced polymer [CFRP], Glass fiber-reinforced polymer [GFRP], and steel) bars, and one unstrengthened beam used as a control beam were tested under monotonic static loading to determine the enhancing influence of the fiber-reinforced polymer (FRP) reinforcement. The performance of different bars used to establish the concrete is examined. A general methodology to evaluate the improving flexural behavior of RC beams strengthened with NSM–FRP bars is presented. A quantitative criterion governing debonding failure is established. The proposed bond model assumes linear elastic behavior for the concrete, adhesive, and NSM–FRP bars, following the same philosophy as the American concrete institute [ACI] provisions for bond analysis and design to control the cracks. So FRP reinforcements show substantial deformation before failure when the cross-sectional area is based on a permissible strain during service, so there is no need to check the deformability. The results of the tests show that using NSM–CFRP bars improves the flexural capacity and stiffness of the strengthened concrete beams of other types.

The aim of the present work was to investigate and achieve the optimum compressive strength of self-compacting geopolymer concrete (SCGC). Fly ash (FA) and ground granulated blast furnace slag (GGBFS) are used at different ratios as binder materials to produce the SCGC mixes. Alkaline solution was a mix of sodium silicate and sodium hydroxide. Three different ratios of binder materials were used to produce SCGC (0FA-100GGBFS; 50FA-50GGBFS; and 100FA-0GGBFS). The total binder weight was 500 kg/m 3 within a constant alkali–binder proportion (0.5). Two curing conditions were used, at ambient environment and heat curing at 110°C for 24 h. The compressive strength and fresh properties of SCGC are evaluated. The compressive strength is utilized to demonstrate the mechanical properties of SCGC. The compressive strength is investigated at two ages (7 and 28 days). The results showed that the use of GGBFS had a negative effect on the fresh properties of SCGC. However, it has a significant impact on the mechanical behavior of the SCGC. SCGC’s early strength is heavily involved in heat curing. The compressive strength of 100% GGBFS in the ambient environment after 28 days was more than that of GGBFS cured at 110°C. The optimum eco-friendly mix is 50FA-50GGBFS.

The visual scene represents the scope of vision or what the eyes see (image or an appearance) and is perceived by the senses, as well as it is the place of the event and natural and physical design elements. So, the relationship between the design scenes and the user is important because it has psychological and physiological effects to achieve human needs such as the safety, which is one of the human needs. Scenes’ design plays a role in stimulating a sense (safety or fear) and is reflected during the person’s performance of various activities in the space. Recently, a phenomenon of insafety and fear has spread in children’s schools, and many studies have recorded that this phenomenon is common in 2–5% of children and adolescents, and 4–5% of children in the primary stage suffer from anxiety disorders that prevent them from practicing their studies normally. Through a pilot study of the Iraq schools, it was found that 55% of them suffer from insafety and fear. This research is an attempt to study the relationship between the scene temporal rhythm to stimulate children’s (safety and fear) feelings. To achieve the aim of this research, a descriptive and analytical methodology was adopted with two theoretical and practical axes. Finally, the results and conclusion show that there is a relationship between the temporal rhythm characteristics and the type of scene that affects the behavior patterns and diversity activities (it means that it stimulates a sense of safety for children in the educational space).

Extreme conditions will cause the water level of high fill canal segment to change suddenly, which will affect the velocity and pore pressure of the slope. A 9 km irrigation earth canal in the city of Alsyahy, 15 km away from Al-Hilla city, and branching off from the left side of Shatt Al-Hilla at 57 km, was studied. The aim of this work is to study and analyze the effect of rationing system on the Birmana earthen canal during rapid drawdown case. Finite element modeling with Geo-Studio software was used in the present study to analyze the combined seepage and slope stability for three cycles. The resulting minimum safety factor obtained from the analysis using the saturated and unsaturated soil model was found to be 1.161, 1.142, 1.159, and 1.2 from the Janbu, Bishop, Morgenstern-Price, and Spencer methods, respectively. The factor of safety (FOS) values in three cycles are less than the required value. Finally, the FOC decreased by 66% from its value before the rationing system was applied, the area of canal and slip surface increased by 77 and 14%, respectively, due to the applied rationing system. These changes led to an irregular water distribution along the canal, in addition to a reduction in road width.

One of the most critical engineering problems that occur in the foundations of machines resting on soil is the problem of the transmission of vibration from the machine to the foundation and then to the soil. This leads to increased stresses on the soil layers and increased settlement as well. In this article, an experimental model of the foundation of a rotary machine foundation located on gypseous sandy soil (36% gypsum content) has been studied. The weight of the machine model with the foundation was 26 kPa subjected to 10 Hz frequency. The study comprises investigating the effect of embedment depth on the behavior of the rotary machine foundation. The results indicated that resting the foundation on the surface of the soil leads to an increase in the amplitude displacement and the pressure in the region under the foundation. The increased embedment of the foundation to half the thickness of the foundation (0.5H) leads to a reduction in the displacement of the foundation. The amplitude displacement values remained within the permissible limits, while the settlement decreased about 37%. The increased embedment of the foundation to 1.0H gives more stability to the foundation, and increases the pressure in the soil layers, while the settlement decreases about 50%.

Structural buildings consist of concrete and steel, and these buildings have confronted many challenges from various aggressive environments against the materials manufactured from them. It contains high water levels and buildings whose concrete cover may be damaged and thus lead to the deterioration and corrosion of steel. It was important to have an alternative to steel, such as the glass fiber reinforced polymer (GFRP), which is distinguished by its great effectiveness in resisting corrosion, as well as its strong tensile resistance. Still, one of its drawbacks is that it has a low modulus of elasticity. This research article aims to conduct a numerical study using the nonlinear finite element ABAQUS program on eight beam models with various parameters such as stirrup spacing, compressive strength, reinforcement layer, and type of bar reinforcement under four-point bending. The result shows that the ultimate load capacity of the GFRP beam is higher than that of a beam reinforced with steel and the number and width of cracks are greater in the GFRP-reinforced beam than in the steel-reinforced beam. In general, the serviceability reflected by cracks and deflection is lower in GFRP-reinforced beams than in steel-reinforced beams with higher serviceability. The results, on either hand, showed the expected behavior of GFRP, which is linear elastic to the failure stage. These beams are divided into four groups of beams with different variables studied to understand GFRP bars’ behavior under static loading. The variables taken in this study are the spacing between the stirrups, the compressive strength of concrete, the effect of the number of layers of reinforcement, and the type of reinforcement bar.

Many empirical equations have been proposed in the past to predict the parameters of the one-dimensional normal consolidation line (1D-NCL) for soils. However, applications of these equations are limited to specific range of pressure and plasticity soils. General empirical equations for 1D-NCL for large range of pressure and plasticity soils are presented in this study. It is assumed that the 1D-NCL has up to three slopes and these slopes start at different stresses depending on liquid limit (LL) of soils. The 1D-NCL of 59 different soils for a large range of LL (19–520%) was used to establish the initial part of 1D-NCL. The soils were categorized based on their LL into two groups: (i) LL < 110% and (ii) LL > 110%. The equations for initial part of 1D-NCL were compared with the previous empirical 1D-NCL equations. The comparisons showed that the new 1D-NCL equations have a better agreement with tests results, especially for highly plastic soils. Moreover, two soils with different plasticity were used to verify the new 1D-NCL equations. The verifications showed a good agreement between the experimental and the predicted results.