Composite columns are often used in constructing high-rise structures because they can reduce the size of a building's columns while increasing the usable area in the floor plan. This research aimed to develop a nonlinear 3D finite element analysis model using the ABAQUS, version 6.13-4, of various round composite column designs with varied multi-skin of tubes for solid and hollow columns subjected to various eccentricity loads (90, 180 mm). Extended data to another 12 specimens of composite columns by numerical method, based on six references experimental data of composite columns. The results of ABAQUS data in this study show that; increasing eccentricity for applied loads causes a decrease in loads to fail for composed columns. The ultimate load of hollow composite sections under eccentricity is lower than solid composite sections under different eccentricity loads. Also, the same results indicated fort eccentricity loads. The same results indicated an increased number of steel layers. The stiffness of concrete is greatly influenced by its strength. When the concrete strength rises, the stiffness of the composite column rises as well. The ratios of concrete compressive strength values according to the reference column (CC1S00 with fc’=31.96 MPa) were (-4.4, 3.1, and 6.5) percent for the specimen (CC1S00) with (fc’=25, 35, and 40) MPa, respectively. The method utilized is in the nonlinear analysis, and the finite element results are in good agreement with the experimental results.
This study investigates the driver behavior of a certain number of drivers using a questionnaire method. The questionnaire contains a part of drivers' demographics, including age, gender, and the type of transportation most used by the drivers. It was divided into three parts. Each part deals with a specific type of road in Baghdad City: multi-lane, two-lane, and local. The questions were about the number of times they drove the vehicle on each type of road, the speed at which they drove the vehicle and did not cause accidents, the distance traveled during the last week on each type of road, and the number of times the speed limit was exceeded. The most prominent reasons for increasing the speed of drivers were also indicated, and solutions were suggested to reduce the speed of drivers. The results show that the driver's age was considered an important factor in the driver’s behavior. It was found that the older the driver, the more committed he was to the proposed speed limits for each type of road. In addition, spreading public awareness about speed reduction to reduce violations and accidents is vital.
Helical piles are a kind of foundation that can withstand compression, tension, and lateral stresses. However, this kind of pile was utilized extensively globally for almost 25 years. Its behavior, particularly in Iraq, is uncertain and frightening. The current research used the finite element technique to analyze this kind of pile. The helical pile geometry was suggested to be modeled using the finite element method using the computer software Plaxis 3D The soil used is medium sandy soil. Additionally, parametric analyses were conducted. The primary parametric research examines the impact of helix number, helix spacing, helix diameter, and helix configuration under cyclic load. The main results are more helices in a pile, the lower the amplitude of settlement (in the direction of z) compared to a pile without helices. As a result, the amplitude of settlement in the case of two helices decreased by 81.6 %, while the amplitude of settlement in the case of three-helix decreased by 77.74 %. In the case of three helices, the higher spacing between the helices, the lower the value of the amplitude of settlement (in the direction of z). The effect of the number of helices in the hardening soil model is more than the effect of the number of helices in the Mohr-Coulomb. As a final result, increasing the number of helices in a pile has a more significant effect in reducing the amplitude of settlement than increasing the between the helices.
Global warming induces to increase of greenhouse gases in the atmosphere and plays a crucial role in determining the future trend in climatology and hydrology of a watershed. This paper aims to investigate the implications of global warming on future climate and its consequents on streamflow of the Adhaim River Basin (ARB). For this purpose, the Long Ashton Research Station-Weather Generator (LARS-WG) and Soil and Water Assessment Tool (SWAT)-Based models were implemented. The climate and hydrologic records for the period 1990-2019 were used as a Reference Period (RP) and projected to 2080 under Representative Concentration Pathways (RCPs 2.6, 4.5, and 8.5) and five Global Climate Models (GCMs). The results show that the region of ARB tends to become hotter and drier with an increase in mean temperature by 1.2, 2.9, and 4.6 °C under the considered RCPs, respectively. However, precipitation tends to decrease from 366 mm/y in RP to 320.2, 302, and 300.5 mm/y by 2080 under the considered RCPs. Consequently, the streamflow will decrease to about 28, 26, and 24 m3/s by 2080 under the considered RCPs, respectively, compared with 28.96 m3/s in RP. Therefore, adaptation strategies are highly recommended to alleviate the negative impacts of climate change, and the implications of climate change on groundwater, water demand, and adaptation plans should be investigated in future studies.
Three-dimensional (3D) real scale models delivered from digital photogrammetric techniques have rapidly increased to meet the requirements of many applications in different fields of daily life. This paper deals with the establishment of a 3D real scale model from a block of images (18 images) that were captured by using Canon EOS 500D digital camera to cover a test field area consisting of 90 artificial target points, 25 of them are ground control points (GCPs) while the remains are checkpoints (CPs). The analytical photogrammetric processes including the calculation of interior orientation parameters (IOPs) of the camera during the camera calibration process, exterior orientation parameters (EOPs) of the camera in each capturing, and the object space (ground) coordinates of the model are calculated simultaneously based on collinearity equation using bundle block adjustment method (BBA). Assessment and validation of the accuracy of the results is an important task in this study that was implemented to determine and analyze the errors of 3D coordinates through linear regression analysis (LRA). Root mean square error (RMSE) is the statistical parameter that was used in the statistical analysis of results. The standard error is another statistical parameter which also used to evaluate the accuracy of locations and rotation angles (EOPs) of cameras. The total RMSE (RMSE)xyz of GCPs is ± 2.530 mm while the total RMSE (RMSExyz) of CPs is ± 2.740 mm. The overall accuracy of the work is 5.000 mm.
Land Surface Temperature (LST) is a critical parameter for water resources and hydrology investigation. Weather ground stations provide a continuous dataset on the LST. However, some stations rely on discrete events data, which shows limited capabilities to monitor diurnal and annual changes in LST. Remote Sensing technology provided much valid information by using Moderate Resolution Imaging Spectroradiometer (MODIS) to cover LST variations in Iraq. This study aims to analyze LST variation based on MOD11C3 Data with weather ground measurements stations for the different topography periods between 2000-2020. Different statistical parameters were used to validate LST results, including RSME; NSE; R2
, and Parson Correlation. The results indicate agreement between MODIS and ground measurement stations during the winter season. The values ranged: RSME (close to zero); NSE (0 to 1); R 2
(between 0.5 and 1), and Parson Correlation (between 0.51 to 1).In spring, the values ranged: R 2
(between 0.5 and 1) and Parson Correlation (between 0.51 to 1). As the temperature rises during seasonal changes, the congruence in the four statistical indicators begins to decline dramatically. However, Baghdad, Basra, and Mosul stations still appear in good agreement, which is the validity of the data issued by MOD11C3. The finding presented in this research shows that the results of the LST by MOD11C3 are in good agreement and acceptable despite in various topographies of the ground stations.
Batter piles or raker piles are the piles driven in the soil at an inclination with the vertical to resist inclined forces or large lateral loads. Battered piles are widely utilized to support offshore buildings, towers, and bridges since these structures are risky due to the exposure to overturning moments resulting from winds, waves, and ship impact. This paper used a three-dimensional finite element analysis using PLAXIS 3D software to study the effect of several variables that affect the behavior of batter piles in a group under pullout loads. The study is conducted on a steel pipe pile model embedded in a dry sandy soil with three different relative densities (loose, medium, and dense sand) at different inclination angles and three embedment ratios L/D of 25, 37.5, and 50, respectively. The finite element model was carried out on a pile group of 2×1 with different configurations. The numerical results indicated that for all pile configurations, the pullout capacity of the batter pile group increased when the embedded ratio and relative density increased, and the maximum value was attained at a 20° batter angle. Furthermore, batter pile groups with BB (group with two battered piles) configuration of (-20°, +20°) gave a high resistance to the pullout load compared to other configurations of the pile group. In addition, pile Groups with battered piles marked the resistance to the pullout load more than pile groups that contain only the vertical piles.
The use of biochar as a soil amendment has been the focus of many studies. It is believed to improve soil characteristics and increase crop yields. Still, a diverse range of feedstocks needs to be researched and converted to biochar for environmental purposes.To achieve sustainable biochar, it is favorable to be derived from residues available locally, and particularly interesting are those that have been turned to biochar near the application area. This study investigates the effects of locally date palm-derived biochars produced at four different temperatures (250, 350, 450, and 550o
C) for 60 minutes on soil physicochemical properties, mainly; pH, bulk density, and total nitrogen availability. The biochar application ratios were 5% and 10% by weight to each soil sample. The soil was gathered from a local farm near Al-Kargoulia, textured as clay loam, and had a total nitrogen content of 25 mg/kg. From mixing through incubation, the experiment lasted 30 days. Biochars produced at (250-350o
C) have a minor impact on soil characteristics, whereas biochar produced at (450-550o
C) had a higher effect on soil properties. Bulk density was decreased due to biochar’s high porosity (up to 90%), while pH increased from 7.23 to 8.5. In contrast, nitrogen was affected highly and increased to 32.33 mg/kg.
In recent years, Open Graded Friction Course OGFC is becoming more common in some countries. It is applied to improve surface frictional resistance, minimize hydroplaning, reduce water spray, improve night visibility, and lower pavement noise levels. These functions are carried out primarily by removing water from the pavement surface during a period of rain. Also, it has many disadvantages which as poor resistance to permanent deformation, low fatigue strength, high stripping, and moisture susceptibility. The paper aims to investigate the probability of using Cellulose Fiber (CF) as a modifier to improve the properties of OGFC asphalt mixture. In this research, one type of asphalt grade (40-50) and one gradation (19 mm Maximum Aggregate Size MAS) were used. Three percentages of CF (2%, 4%, and 6%) were added to asphalt cement to obtain the modified mixtures. Optimum asphalt content was selected by evaluating the following criteria: air voids content, asphalt drain down, abrasion resistance, and permeability. Several laboratory tests such as Indirect Tensile Strength (ITS), moisture susceptibility, Marshall stability, and flow were evaluated for modified samples, and their results were compared to the original open-graded asphalt mixture. The outcomes indicated that cellulose fiber greatly enhanced the mechanical properties of OGFC mixtures, increasing moisture damage resistance by 19.4%. Furthermore, Marshall stability improved by 38.92 % as the abrasion loss is decreased by 15.85% with adding of CF for aged samples.
The coefficient of lateral earth pressure at rest (K0
) explains the connection between the effective vertical and lateral stresses. Geotechnical engineers have studied K0
for many years for its being a key element in the designs and analysis of various geotechnical problems such as slope stability, piles, and earth retaining structures. Moreover, K0
has played a critical phase in any numerical study of the soil-water combined geotechnical boundary value issues requiring parametric stress-strain time formulations During the previous few decades. A modified apparatus consisting of a standard Oedometer equipped with Force Sensitive Resistance (FSR) is used to investigate the value of lateral pressure () due to the vertical stress. The Oedometer test is carried out on three samples with different organic contents, with the K0
values obtained from each sample; empirical equations were also used to estimate K0
values for comparison purposes. From the analysis of the results, it can be stated that the K0
value is inversely proportional to the organic matter percent in the soil. It varies from 0.6125 in soil with 25.1% organic percent to 0.76 at a percent of 9.8%. The Force Sensitive Resistance (FSR) technique's performance is practical enough for estimating lateral earth pressure at rest (K0
) of normally consolidated organic soil with many advantages; it is far less time-consuming and has a low operating cost than the traditional K0
estimate methods. Furthermore, K0
decreases with the increase of organic content.
This paper investigates the impact of the plant fly ash (dry tree leaves) addition on the geotechnical properties of the landfill soil, where an engineering laboratory landfill simulating a real landfill was manufactured. Two percentages of plant fly ash (10% and 15%) were used to reduce or prevent the penetration of heavy metals resulting from the decomposition of landfill waste into the soil and conducting laboratory tests such as the Atterberg test, specific gravity test, compaction test, permeability test, SEM test, and heavy metals analysis. The results of laboratory tests indicate a decrease in the plastic limit and the liquid limit with the addition of plant fly ash, as well as a decrease in the specific gravity and a decrease in dry unit weight with an increase in the need for water content when adding plant fly ash. In contrast, the permeability increased with the addition of plant fly ash. In the most important laboratory test, which is the chemical analysis of soil metals, the soil improved with plant fly ash gave results indicating a lower level of metals pollution at depths of (10 cm, 20 cm, and 30 cm) of soil layer compared to natural soil. The analysis was conducted on 7 basic pollutants (cadmium, copper, iron, Manganese, Zinc, Chromium, and lead), where the percentage of pollutants decreased in improved soil compared to natural soil under the same conditions by (50%, 74%, 62%, 68%, 60%, 68%, and 55%) respectively.
This research aims to study the benefit of using fibers made from waste materials in concrete and evaluate the ability to use these fibers as a substitute for commercial fibers. Different aspect ratios of alternative fibers formed from cut steel tied wire waste were utilized. This material is selected because of its low price and wide availability. Two concrete mixes with 15% waste crushed clay brick coarse aggregate reinforced with different volume fractions of 1.0 and 1.5% and an aspect ratio of 40 were prepared. Also, three concrete mixes reinforced with a hybrid aspect ratio of 40 and 65 of tied wire waste steel fibers (TWWSF) with different volume fractions of 1.0% and 1.5% were prepared. The compressive, splitting tensile, flexural strengths, and ultrasonic pulse velocity (UPV) of all prepared concrete mixes were tested. The results illustrate that the inclusion of tied wire waste steel fibers significantly enhances the strength of concrete with 15% waste crushed clay brick coarse aggregate, and high-performance concrete with compressive strength of up to 85 MPa can be produced. The enhancement in compressive, splitting, and flexural strengths were 29%, 42.8%, and 38%, respectively, for concrete reinforced with a fiber aspect ratio of 40 and volume fraction of 1.5%. In comparison, for the same volume fraction, the percentage was 22%, 48%, and 44%, respectively, for equal content of hybrid aspect ratio of 40 and 65.
Increasing the cross-sectional area of the piles or adding wings to the piles are two strategies for increasing the bearing capacity of the piles to resist lateral stresses. Small and full-scale finite element models were used to investigate the effect of adding the wings on the laterally loaded pile bearing capacity in this study. Four embedded ratios (4, 6, 8, and 10) were used with various wing dimensions and numbers. The results showed that adding wings to the pile increases the resistance to lateral loads and reduces the lateral displacement significantly. +To achieve the highest lateral resistance, the wings should be fixed parallel to the lateral load applied to the pile and close to the pile head. The ultimate lateral applied load is proportional to the rise in relative density. The lateral pile capacity was increased by 16.5%, 18.4%, and 33% in dense, medium, and loose sand, respectively, at the same length to diameter ratio (L/D). Increasing wing length improves lateral capacity significantly. At a failure, the lateral pile capacity was 18% and 8.5 % for Lw, equal to 112 mm and 56 mm, respectively. Another study's purpose was to determine how increasing the number of wings affected pile resistance. The lateral pile capacity at failure was increased by 9.8 % for two wings, 18.4 % for three wings, and 18 % for four wings.
The temperature and stress caused by the load can be cited as two main parameters leading to breakage in asphalt pavement, especially rutting (permanent deformation). So, to reduce the problems of rutting of roads, several actions have been taken, including improving pavement quality and the structure design methods. The increase in the attention of respective engineers in the last few years to modify and improve the asphalt performance through providing different types of additives and replacing the raw materials of asphalt mixture with recycled materials to improve the environment and reduce the cost of modified pavement mixture. This study discussed the use of low-density waste polyethylene as an asphalt modifier in percentages of (2, 4, and 6) % by the weight of asphalt and their impact on the performance of asphalt mixtures at high temperatures. This study showed that using plastic waste (low-density polyethylene) as a bitumen modifier improved the performance of asphalt mixtures at different high temperatures. This was achieved by reducing the rut depth by (80.5) % and (82.3) % at temperatures of 50 C and 60 C, respectively, using low-density polyethylene waste at an optimum value of about 4% by weight of asphalt in addition to enhancing the Marshall stability by using this percentage of polymer.
Introducing nanotechnology to the pavement industry witnessed a great interest due to the proven benefits of nanotechnology in various scientific fields. However, the reduction in the binder's characteristics might be disadvantageous to the durability of the recycled mixture, making it more susceptible to external factors such as moisture. Therefore, using nanotechnology is expected here to treat this issue. The goal of the current paper is to report on the influence of the nano-clay montmorillonite (MMT) powder (MMT k10) on the resistance to moisture in the hot recycled mixtures or the Reclaimed Asphalt Pavement mixtures (RAP mixtures). In this work, different proportions of rejuvenated RAP were employed. These proportions are 30, 40, and 50% as a percent of the overall weight of the mix. The percentages were mixed with a nano-modified neat binder with (0, 1, 3, and 5)% nono-clay MMT as a proportion of the bitumen’s weight. Two types of mixtures are prepared and used in this paper: nano-modified RAP mixtures and unmodified RAP mixtures. On both types of mixtures, the compressive strength test, the index of retained strength (IRS), the indirect tensile strength tests (ITS), and the tensile strength ratio (TSR) were carried out to compare and evaluate the moisture resistance of rejuvenated RAP mixtures. The experimental test results indicated that using 5 percent nono-clay in regenerated RAP mixes provides better performance than not using it. where it increased moisture damage resistance by5.53% for IRS value and 3.66% for TSR for 50 percent RAP mixes.
The harnessing of glass waste, which is slow to decompose and has high recycling costs, is in the interest of supporting and stimulating a balanced construction pattern that is interdependent on the living environment. Consumable food and drink bottles are one of these forms of waste that can be calibrated to meet desired specifications. Controlled low-strength materials with low and deliberate strength for future excavation have highly desirable rheological properties, active hardening, and zero or rare separation of materials can be maintained with waste glass substitution. In this study, an experimental evaluation was commenced to estimate the practicality of waste glass (fine and coarse powder) by replacing fly ash and natural sand with it to control low-strength materials. A sum of seven slurry blends was intended by employing several ratios (10%, 30%, and 50%) of fine and coarser waste glass. Some characteristics of plasticity and hardness were observed, such as fine glass decreased flowability. In contrast, coarser glass decreased dramatically, exceeding the minimum limit of 20%, which necessitated the use of superplasticizer in a proportion that corresponds to the increase in the replacement. Unit weight slightly increased with fine glass substitution, but in the Coarser substitution, a steady decrease occurred. The compressive strength of 28 days in fine glass replacement is less than the reference mixture, but it exceeded it at 90 days. A mixture incorporating coarse waste glass was higher at 28 days and developed at 90 days.
The types of post-setting curing and high range water reducing (HRWR) admixture used in Ultra-High-Performance Concrete (UHPC) mixtures play significant roles in determining their rheological and mechanical properties. This study compares the performance of three types of HRWR admixtures commercially available when added to UHPC mixtures under three different curing regimes. Mixtures made with the different superplasticizers were evaluated for their flow, 45mins flow retention, and setting time as fresh mix properties. Compressive strength was also tested for each mixture after 3, 7, and 28 days of curing at the investigated various curing regimes. Sika Viscocrete 180GS produced the highest mixture flow and flow retention levels with a 241 mm flow and 93.7% flow retention. Sika Viscocrete 168-1 produced the best results of setting time with 3 hours as compared to 12 hours with Sika Viscocrete 180GS. Using Hyperplast PC-202, the required 150 MPa compressive strength was secured as early as 3 days of curing with a 48hrs-90ºC curing regime. Using the same HRWR admixture, compressive strength values slightly lower than 150 MPa were reached after 7-28 days when the 72hrs-60ºC regime was adopted. The last curing regime was recommended for producing architectural UHPC units to minimize the delayed formation of ettringite.
Pile foundation bridges are structures extending in the middle of the sea, so they are subject to currents, waves, and earthquake forces.
This article presents a hybrid simulation that was used with input excitations of different current velocities, wave properties, and earthquake amplitudes to assess the non-linear dynamic behavior of pile foundation bridge piers. Based on the interface between MATLAB and ABAQUS software, the general formulations of fluid-structure interaction (FSI) under combined current-wave and earthquake loads are derived. Hydrodynamic and earthquake loading is consistently introduced by creating synthetic time histories of combined current-wave actions and spatially variable ground motion. The behavior of the dynamic model of a deepwater pile foundation bridge for the Songhua River in northeast China was adopted as an example of the study. The accuracy of the created model was verified using prior experimental and analytical computations. It is demonstrated how both linear and nonlinear dynamic behavior performs at various water depths under coupled current-wave-earthquake loading conditions. Revealing interesting aspects, particularly in terms of relative displacement, acceleration, shear, and moment response are shown. The results showed that the hybrid model is an efficient of simulating accurate predictions of the hydrodynamic pressure during earthquake actions for structures in coastal areas.
This paper implemented an HEC-RAS-based steady two-dimensional hydrodynamic model to evaluate the hydraulic characteristics and Sediment Transport Capacity (STC) of the Makhool-Samarra Reach of the Tigris River, where this part is not already investigated. This model was prepared with the aid of topographical surveys, hydraulic measurements, and laboratory tests, as well as recorded data. The main findings show that the flow velocities within most of the studied reach are considered high compared to the local and worldwide flow velocity ranges in natural rivers. Also, the Toffaleti sediment transport function with the Van Rijn fall velocity and the effective depth-to-width computation methods are the most compatible and suitable methods for computing the Sediment Transport Potential (STP) in the
studied reach. With the maximum flow, the computed STP was less than the average (5.7×
tons/day) in 45% of the reach length, where the maximum STP is 8.7×
tons/day. However, with the minimum flow, the STP intermittently fluctuates below the average (0.2×
tons/day) in 48% of the reach length, where the minimum STP is 0.14×
tons/day. Generally, these STPs are little more than the Tigris River in Mosul and much higher than that in Baghdad. Also, these STPs are considered high on a global scale, especially during high flow. Medium gravel is the larger grain gradation class that can be transported. It constitutes less than 0.00005 % of the STP. Furthermore, the STC computations clearly show that the suspended sediment is the dominant part of the STC and the bed material constitutes less than 0.002% of the STC of the total load. However, most of the STC
concerns the clay and very fine silt.
Renovation of the naturally existing area for ecotourist and investments that attracting site-visitors, picnickers and tourists for Iraq, Kurdistan Region, Sulaimani need to promote a reliable decision-making technique so as to raise the level of the tourist-based economy. In this study, the most available public well known and recognized tourist and picnic area by the people and associated governmental directories were studied and assessed for their tourism reliability and capacity. The study area of this research covered tourist area and they were forty-three (43) locations and all the related data collected, analyzed and categorized as main and sub-main criterions. The analytical hierarchy process (AHP) has been used for assessment of that area which was ranked accordingly from the highest to lowest capacity and efficiency’s reliability of tourism. The opinion of experts from tourism agencies, related tourism officials and people from the local area also taken into consideration and translated and used in the AHP assessment tool. Weight factors of the main and sub-main criterions were founded and analyses for their inconsistency. The main criterions and their pairwise weights as per AHP assessment were climate, available green area, root distance, easy of transportation, essential requirements, entertainment tools, provided security and healthcare, respectively.
In this paper, the self-sensing properties of cementitious composites under compressive loads were investigated by utilizing hybrid functional fillers, which are responsible for creating an electrical network that is used to build the self-sensing capability within the traditional cement-based mixtures. Most of the previous works depict the self-sensing capability with the aid of one type of functional fillers or fibers. The present paper attempts to utilize two types of functional fillers, representing a gap filling within the subject. Four hybrid proportions of Graphite (G) (wt.%) and carbon fibers (CF) (vol.%) were introduced. These are (0.5, 1.0), (1.0, 0.75), (1.5, 0.50) and (2.0, 0.25) respectively. In addition to carbon-based materials, polypropylene, polyolefin, and steel fibers are used as reinforcing fibers. One type of fiber was utilized in each manufactured mixture with a constant rate of 2% by volume of the mixture. A plain mixture without functional fillers has also been manufactured. The samples were non-destructively tested by an ultrasonic device before a uniaxial compression test was performed. To verify the self-sensing properties of the manufactured samples, the electrical resistance of the samples was recorded during load application each second. The self-sensing behavior was better for mixtures containing high dosages of graphite with respect to the fractional change in electrical resistivity (FCER). Steel and polyolefin fibers showed good results in terms of compressive strength behavior. However, polypropylene fibers showed the lowest compression strength among all types of reinforcing fibers used.
In the current work, an analytical solution for static bending analysis of the thick rectangular plate structure was obtained using three-dimensional plate theory. First, the energy equation was formulated from the static elastic principles and transformed into a compatibility equation through general variation to get the slope and deflection relationship. The solution of the compatibility equation gave rise to the exact polynomial deflection function. In contrast, the coefficient of deflection and shear deformation of the plate was obtained from the governing equation through the direct variation method. These solutions were used to obtain the characteristic expression for analyzing the displacement and stresses of a rectangular plate. This formula was used for the solution of the bending problem of rectangular plate support conditions of two clamped edges, one free edge, and a simply-supported edge (CCFS). The result of the deflection and stresses decreases as the span-thickness ratio increases. More so, the aspect ratio effect of the shear stress of isotropic plates is investigated and discussed after a comparative analysis between the present work and previous studies. The result shows that the present study differs with RPT) of assumed deflection by 2.7%, whereas exact 2-D RPT by 1.9%. This shows the efficacy of the exact 3-D plate theory for rectangular plate analysis under CCFS support and loading condition.
In this paper, the SPSS program (version 25) and Binary Logistic Regression Model were used to implement and identify the risk factors that affect traffic accidents on Baghdad highways. Due to the increase in the number of traffic accidents that led to injuries and deaths in Iraq during the past years and the lack of specialized studies in traffic accidents, especially on highways, this required the preparation of a study to know the causes of accidents and to explore the factors that have a relative impact on (the severity of the accident). Four highways in the capital, Baghdad, were chosen in this study, major and vital in terms of the number of drivers who use them daily, which are (Mohamed Al-Qasim Expressway, Army Canal Expressway, Salah Al-Din Street (Expressway), and Baghdad International Airport Street (Expressway)). Three hundred and forty-nine traffic accident forms were collected from the traffic directorates on both sides of Al-Karkh and Al-Rusafa for the years from 2006 to 2019. After the analysis by Binary Logistic Regression, the results showed that (contributing factors, road condition, cause of an accident like (parking on highway, loss of control, lack of attention, sudden stopping and lack of attention), vehicle body type, speed). Resulting from the BLR model.
In this paper, the Abaqus 6.14 version program was used to carry out a three-dimensional finite element analysis to predict the rut in the asphalt laboratory model. In a previous study, a cylinder model of asphalt was tested under the influence of traffic loads and temperature. The test was simulated using the finite element method considering the boundary conditions, load steps, and temperature. The cohesive zone model (CZM) approach was used in the Abaqus program to analyze the spread of the rutting in the model to simulate the fracture and improve the sample structure and the materials used. The Abacus program analysis showed satisfactory results when compared with the experimental results. The numerical and experimental displacement results indicate that the program can simulate the rut that occurs in the model. Using a temperature of 55 ° C showed that the effect of the temperature was not noticeable. XFEM-CZM coupled model provides a suitable numerical tool to represent the rutting tests.
In this study, push – out test specimen is proposed to explore the behavior of shear connectors in timber–concrete composite beams. Since there are no standard shapes and dimensions for determining the strength of connectors, push–out specimens such as those used for steel-concrete composite beams are suggested to study the behavior of connectors in timber concrete composite beams. Four specimens are tested. Two of these specimens are with one connector per side. The other two are with two connectors per side. The load and slip are recorded during testing. The results show that the ultimate load per connector ranges from 24.9 kN to 29.4 kN, with an average value of 26.9 kN. An equation is proposed to determine the ultimate load of the connector. Good agreement is achieved between the theoretical and experimental results. An average value of 0.98 is obtained for theoretical to experimental results.
In Iraq, due to WWTPs being old and outdated, an evaluation of the maintenance management is needed to highlight the points of weaknesses and strengths of the plants. In this paper, the strength, weakness, Opportunities, and Threats (SWOT) analysis model is designed with the Delphi Technique and Liker-scale and applied to the old Rustumiya project in Iraq (ORP). The design and application of this model are based on the design, operation and maintenance drawings and reports, and field visits to the ORP. In addition, three rounds of the questionnaire were sent to more than 80 experts varied in qualification and experience, considering the SWOT elements of the methods, materials, and human resources issues. The weight, relative importance, and implementation of each item in each SWOT element and the SWOT elements and issues were computed. The results showed that in the internal elements, the degree of importance of the weakness has a higher value of importance than the strength. In the external elements, the opportunities are considered more important. For the four issues, methods have the lowest weight while the materials have the highest. This alerts the major development required in this sector for a new plan for selecting and preparing maintenance materials. However, human resources come after the materials in terms of importance. The developed SWOT analysis model is beneficial for evaluating WWTPs with simplified and realistic results. Further, it can evaluate other projects like irrigation projects and water treatment plants.
In arid and semi-arid areas, assessing the potential impact of climate change on water availability is of critical importance for achieving better management of future water resources. Iraq as one example of those areas is expected to experience more stress on water due to the climatological characteristics and to the rapid population growth in addition to the policy of the riparian upstream countries. Therefore, the present study aims to quantify the impacts of climate change on the Khabour River catchment north of Iraq, which is one of the riparian catchments between Iraq and Turkey. The HEC-HMS model was firstly calibrated and validated against daily streamflow data measured for the period 01Jan2004-30Jun2009 near the catchment outlet at Zakho station. Thereafter, the future climate changes data from the HadGEM2_ES model was fed into the calibrated HEC-HMS model to quantify the future water resources availability. The impacts of climate change on the water under four possible scenarios of RCPs (RCP2.6, RCP4.5, RCP6, and RCP8.5) of atmospheric greenhouse gas (GHG) concentrations for three future slice periods (2021-2030), (2041-2050), and (2061-2070); was assessed in attribution to that from the period (2000-2009). Results show that the implemented HEC-HMS model was superior in modeling the streamflow data. NSE, R² and RMSE value was 0.871, 0.89 and 26.7, respectively, for calibration and 0.936, 0.9364 and 18.0, respectively for validation. The results also suggest that annual river runoff will likely decrease under all scenarios of RCPs and time stages of the future period.
Skirted foundations are one of the solutions proposed to increase the bearing capacity of the soil. They assist in increasing the load and depth of failure in weak ground or soils with low shear resistance and reducing the foundation settlement if a soil improvement method cannot be applied or the cost of implementing deep foundations increases. This study examined and investigated the extent of soil bearing of skirted foundations on sandy soils and studied the effect of soil saturation cases and three cases of water content reduction to measure the matric suction value of unsaturated soil. A physical model was created to simulate the strip foundation and compare these cases (dry-fully saturated-partially saturated). It was found that the soil load carrying capacity in the case of unsaturated soil is the highest, where matric suction is at a depth of 450 mm, followed by the dry case and then the saturated case as it represents the weakest state of the soil.
Interest in how roundabouts can most effectively be used continues to increase to achieve goals of safety, efficiency, along with other benefits. This research presents the most important element of the operational performance of roundabout traffic intersections in Baghdad city on capacity analysis. The obtained results for critical headway time are (3.35 sec) and (2.8 sec) for the Main west and East approaches. Also, the critical gap value for the West and East approach is less than the range of (NCHRP 572), possibly attributed to the congested traffic volume in Al Turkman roundabout with aggressive driver behavior. Calculating in the west and East approaches peak period (1:00-2:00) pm to describe the rejected and accepted gaps with ranges from (1.00 – 5.00) sec, the main aim of this research is to model the critical headway by analyzing the data in trial and error technique to determine the shape of the data through Probability density function and Cumulative Density Function, and the Mathematical function that represented, exponential distribution functions for critical gaps with different shape functions scale (1,1.5) for accepted and rejected gaps are better fittings to the empirical distribution, and there is no significant difference. Comparing the observed field data and the theoretical data for the validation process of Rejected and Accepted Gaps are done. A good fit is obtained, and a scatterplot for observed and theoretical data has been drawn for the West and East approaches at peak period (1:00-2:00) pm.
This study aims to shed light on the indicators of environmental change and environmental impact assessment during the past five years in a representative area of the western part of Iraq (BAHAR-ALNAJAF). This is to understand the leading causes that led to the environmental changes from (2016 to 2020) due to the change in land cover in the study area. The paper refers to an environmental study for the study area using satellite data within the software environment (ArcGIS) and the application of remote sensing from two aspects: Ecological indices retrieval and the monitoring environment for land cover. Remote sensing and GIS software have been utilized to categorize (Sentinel-2) imagery into seven land use and land cover (LULC) classes: cropland land, orchards land, wetland, sandy area land, mixed barren land, built-up land, and water bodies. Supervised classification and Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), Normalized Difference Water Index (NDWI), and Normalized Difference Salinity Index (NDSI) were approved and utilized respectively to retrieve its class boundary. From a practical point of view, it was found that there is a rise in water levels in the Bahar Al-Najaf; this rising has led to the flooding of many built-up and vegetated lands. As a result, flooded land areas increased in 2020 to about 50% more than in 2016. Consequently, the built-up growth regions in the study area were very slow to change during the study period (2016-2020). The vegetation cover for 2020 is 56% higher than in 2016 because of the abundance of water and agricultural policy of this year.
Ultra-high performance concrete (UHPC) has a higher tensile strength than conventional concrete by about 6-times, besides a compressive strength greater than 150 MPa. It also exhibits linear and non-linear behavior on loading because of strain hardening and strain softening in compression and tension. Therefore, the effect of these mechanical properties can reflect in the beam behavior produced by UHPC. This paper deals with the methods and approaches adopted by some guidelines and recommendations that transact with the analysis and design of UHPC beams. The prevalent style of the methods is based on the equilibrium of the beam's section for the induced forces above the neutral axis, which represents the compression forces in concrete, and below the neutral axis, which designates the tensile forces in longitudinal rebars and that one in concrete. Since the tensile strength of UHPC is relatively high and cannot be ignored; therefore, it is considered in the analysis and design approach. The flexural capacity depends on the induced moment due to these forces. The structural analysis of UHPC depends on the stress-strain relationship in compression and tension. The linear portion of compression relation continues to about 80% of the compressive strength; therefore, it is considered in the analysis and design process.
Structural strengthening is a method of application to raise the load-ability capacity of building structures to meet the building's need to carry additional and unexpected loads that were not accounted for in the main design. In this study, Ferro-cement was used for strengthening concrete beams. Three locally available wire mesh types were used with an ordinary cement mortar to strengthen reinforced concrete beams under flexural loading. The results show that using a Ferro-cement layer with wire mesh of 15 mm size square opening has the best effect on increasing reinforced concrete beams' bearing capacity and deflection more than when using the other two types of meshes. The first crack and failure load increases were 72 and 79%, respectively. In contrast, the deflection increased 70 and 51% at the first crack and failure load.
Roads and highways are used by different vehicle types, and the heavy vehicles among them can be considered the most critical in loading, which causes failure in the pavement structure and increases rehabilitation and maintenance costs. In this study, the composite effects for wheel loads and temperature were considered in the finite element analysis using Abaqus 6.14. The asphalt layer was modeled as an elastic material, while the base and subbase layers were modeled as an elastoplastic material following the Mohr-Coulomb model. Also, the impact of wheel loads on flexible pavement settlement and the main output of analyzing pavement structure are almost represented by the vertical stresses and the surface deformation, which are considered the critical response point. A single unit truck was tried with two thicknesses of the asphalt layer, 14 cm, and 25 cm, with two different temperatures. Since base and subbase layer thicknesses remained constant, it does not affect the displacement variation. However, it was found that the increase of asphalt layer thickness from 0.14 m to 0.25 m leads to a decrease in the vertical displacement of about 0.59% and becomes 0.77% when the temperature increases to 50℃.
Lake Hemrin is located in the middle east of Iraq, about 50 km from the Iraqi-Iranian border. The lake is the main fish source and provides water for nearby farms. However, due to various socio-economic and environmental management issues, the Hemrin system is a difficult water resources challenge. Moreover, Lake Hemrin receives floodwaters annually over its storage capacity; therefore, there is a risk of flooding in the areas downstream of the lake. To this end, this research developed optimization solutions to design flood escape paths in the area using Analytic Hierarchy Process (AHP) and Genetic Algorithm (GA). Among three initial proposals, i.e., Adhaim River, Wadi Naft, and Salahdin, the developed models optimized each of the proposals and suggested that Wadi Naft would require only 3.88 km3 of cut and fill volume compared to Adhaim River of 34.33 km3. However, the latter would serve more people and agricultural lands. GA and AHP techniques to optimize flood escape paths have shown that these models can discover shorter pathways requiring less cut and fill costs while retaining other flood escape features. The proposed optimal flood escape path can substantially influence the construction of flood-prevention strategies in the area.
This study aims to increase the bearing capacity of the soil by using geosynthetics in a single, double, or triple distribution pattern. The gypseous soil samples were brought from a site near Sawa Lake in Al-Muthanna Governorate with a gypsum content of about (37%), the Soil-Model apparatus of dimensions (60 × 60 × 50) cm with the proposed square footing of dimensions (10 × 10) cm are used in the experimental program of this study. To achieve this goal, a series of (48) different model tests were used on gypseous soil subjected to vertical stress in both dry and wet (saturation) conditions. Depending on the results of load-settlement curves relationships, the ultimate bearing capacity of dry and wet gypseous soil models was determined using the Two Tangent Intersection technique. The results also showed that the number of geotextile layers and the relative density of the gypseous soil samples significantly impact the improvement of the bearing capacity of gypseous soil models. Furthermore, the results showed that the improvement ratio in bearing capacity (BCR%) for gypseous soil models tested after being reinforced with geotextile layer for dry and wet (saturation) at relative density (RD) of 30% and 60% in single, double and triple distribution pattern. The percentage of the improvement in the wet case was higher than in the dry case. It was 143 % in the wet case when using triple-layer geotextile at different depths of reinforcement, while it was 96 % in the dry case.
Hydraulic structures such as surface drainages and culverts are usually constructed in urban areas with the intention of draining runoff into nearby streams and rivers in order to avoid flooding. However, most of these structures frequently fail to serve the intended use due to the occurrence of high intensity rainfall accompanied with long duration, which produce runoff discharge higher than their designed capacities. This is common in many developing countries as drainages and culverts are most times constructed without considering hydrological analysis of the catchment. Hence, this research considered Port Harcourt city as a case study by utilizing 50years rainfall data to develop rainfall Intensity-Duration-Frequency (IDF) curves that will be used for subsequent design of drainages and culverts within the city and its environs. The IDF curves were developed using Gumbel, Pearson type III and Log-Pearson type III distributions at return periods of 2, 5, 10, 25 and 50years. However, the durations considered were 5, 10, 20, 30, 45, 60, 90, 120, 150, 180, 210, 240, 300, 360 and 420minutes. Results showed that the IDF equations developed for the three frequency distributions highly correlate with the observed intensities since there goodness of fit (R2) ranges from 0.9766 – 0.9865. Also, it was noted that there was no significant difference (p < 0.01) between the predicted rainfall intensities from all the IDF equations and the observed intensities. Notwithstanding, the IDF equation developed for Gumbel distribution was recommended to be given higher priority since it has the highest R2 value.
The purpose of this study is to investigate some hardened properties of green self-compacting concrete (GSCC) with 15% volumetric replacements of crushed clay brick waste as coarse aggregate and reinforced with scrap tires recycled steel fibers (STRSF) with 0, 0.25, 0.5and 0.75%volume fraction and 40 as an aspect ratio. Also, a combination of two STRSF aspect ratios of 40 and 60 was used in GSCC as hybrid fiber reinforcement (0.25 and 0.25%, 0.5 and 0.25%, 0.25 and 0.5% of aspect ratios 40 and 65, respectively). Scrap tires recycled steel fibers had been used to improve the properties of the green self-compacting concrete containing crushed clay brick waste aggregate. Dry density, water absorption, compressive strength, splitting tensile strength, flexural strength, and Ultrasonic Pulse Velocity (UPV) were among the properties of SCC that had been investigated. To achieve the purpose of this study, seven concrete mixes were prepared.SCC density, compressive strength, splitting tensile strength, flexural strength, and UPV are all increased with the increase of recycled steel fibers content in self-compacted concrete. Including different volume fractions and aspect ratios of scrap tire recycled steel fibers increased the compressive strength between 2.54% to 23%. The splitting tensile strength was about 5.6% to 13.9%, and the flexural strength increased from 1.6% to 14.8%. All GSCC mixes reinforced with STRSF show good performance according to the classification limits of SCC with high compressive strength, so these mixes are applicable for different weather conditions and construction projects.
One of the most user-friendly alternatives to ordinary concrete is geopolymer concrete(GPC), which achieves the same result. GPC is a unique substance made by activating source materials with a high concentration of silica and alumina. As a result, geopolymer binders use less raw resources and emit less carbon dioxide. For these reasons, most academics are focusing on these sorts of resins to develop eco-friendly housing. This article reports on an experimental investigation that examined the Mechanical Performance of Blended Fly Ash based Geopolymer concrete at 7,28 and 360 days made with two different activator solution molarities and varying R (SiO2
) ratios. Positive findings were seen at a larger percentage of GGBS (36%) with a concentration of a sodium hydroxide solution of 10 M and an R ratio of 2.75, compared with other proportions. The test findings indicate that increasing the concentration of sodium hydroxide (NaOH) solution and R enhances the compressive strength and decreases water absorption of geopolymer concrete.
Biomass’ pyrolysis process is responsible for producing the biochar charcoal, this process does not incorporate the oxygen, and it is utilized as a soil enhancer for each one of the carbon sequestration, and soil health prospects. Biochar can be defined as a stabilized solid which is enriched with carbon and could remain in the soil for extended period of time. Biochar has been studied as a way of carbon sequestration, and it might be a way used for handling climate change and global warming. It happens due to the processes that are associated with pyrogenic carbon capturing and storages. This review is focused on an overview of biochar preparation and application in the environment, previous studies and Applications. Biochar is prepared from various organic materials such as miscanthus, switch grass, corn stover, and sugarcane bagasse. The method of preparation varies with different temperatures and the discharge of nitrogen gas used for a period of one hour not to mention thermal decomposition at different temperatures of heat (500, 600, 700 and 800oC). The success of its use as a adsorbent material, and in treating the soil from heavy metals, its suitability for agriculture, and the treatment of the liquid leachate from solid waste down into the groundwater, in addition to the treatment of groundwater when the topography of the region differs.
According to research, as the depth of a beam increases, the section's shear strength can be expected to decrease. The size effect is a phrase that has been used to describe this tendency. Testing of unreinforced specimens under shear has also shown that the shear strength might be lower than what is typically anticipated in the design. As a result, it is critical to comprehend the behavior of these structures, as they may be influenced by a size impact. Sixteen reinforced concrete beams of different rectangular cross-sections without stirrups were tested. The tested beams were simply supported made of high-strength reinforced concrete subjected to two equal concentrated loads up to the failure. The experimental results showed that all of the beam specimens failed in shear except one which had failed by flexure. Moreover, increasing beam height from 150 to 250 mm has decreased the cracking and ultimate shear strength ratio for all groups except for group four when the beam height increased from 150 to 300 mm the cracking and ultimate shear strength ratio has increased. Furthermore, increasing beam depth from 150mm to 300mm has led to increasing the ultimate load besides decreasing their final deflection at the same level of load, which is the apparent size effect in the stiffness of the tested beams.
This study focuses on studying the behavior of fibrous circular short columns (tied and spirally reinforced) using recycled coarse aggregate (f'c, ft, Ec, and fr) by using recycled aggregates with comparison to normal aggregates with and without using steel fibers. For this purpose, ten (10) short columns were cast at five groups each of two circular columns(tied and spiral of 150 mm radius x 600mm height) with different percentages of recycled coarse aggregate (0%, 50%, and 100%) and different percentages of steel fiber (0%, 0.5% and 1%). The study showed that when adding the 50% normal aggregates with 50% recycled aggregates, decreases of (10%, 18%, 30% and 22%) for (compressive strength, splitting tensile strength, flexural strength and elasticity module), respectively were observed, and when replacing the 100% normal aggregates with 100% recycled aggregates, decreases of (30%, 35%, 58% and 63%) for (Compressive strength f'c, splitting tensile strength ft, flexural strength fr and elasticity module Ec), respectively were observed. The changes on the compressive strength of adding steel fibers to the RAC by a proportion of (0.5% and 1 %) resulted in a significant increase of about (14 % and 35 %), respectively.
A corrugated steel plate girder is a vastly used structural element in numerous fields of application due to its many favorable characteristics. A corrugated web girder, the bending moments, and application forces are only transferred by means of flanges, that the maximum moment carrying capacity is more than any other hot-rolled sections used, while transverse shear forces are only transmitted through a corrugated steel web, webs at a greater depth to a thickness ratio are usually used resulting in slender sections that are susceptible to buckling on the Flat web. The use of corrugated web girders has been increasing in recent years due to optimizations in the automated manufacturing process of corrugated steel webs and a decrease in weight. Thus, to avoid buckling on the web and to obtain maximum strength, corrugations are provided in the area on the web. Corrugated steel plate girder’s ability to be used in numerous fields of application due to its preferred properties. The main advantage of the corrugated web plate girders over the hot rolled girders is the flexibility in the dimensions of the girder. Improvement in the plate girders is essential to take full advantage of this asset. This new achievement has helped engineers to design more optimized structures. This paper provides a review of several studies on corrugated steel web plate girders and plate girders improvement.
Geomatics involves the collection, management, integration, representation, analysis, modeling and display of geographically referenced information describing both the Earth’s physical features and the built environment. One of the main use of this tool is to estimate electrical energy demand throughout Al Anbar Governorate, which have major problems in this sector with about 750 to 770 MW. The consumption of the city of Al Ramadi is about 200 MW. According to official forecasts by the Directorate of Electricity Networks of Al Anbar, this demand is expected to increase to about 900 MW during the summer of 2020. The present distribution systems in Al Ramadi are mostly overhead. Gradual conversion from overhead to underground systems, particularly at the 11 kV level, is recommended, especially in the central part of the city. This will allow for higher system safety and reliability, and for a much aesthetically improved appearance. This necessitated the construction of additional backup stations. Furthermore, prepared a plan for stations that have been constructed in the year 2020, in order to meet the anticipated demand growth during the planning period. Long-term plan for the Governorate of Al Anbar in order to cope with the increased demand for electrical energy.
Ultra-High Performance Concrete (UHPC) is a new generation of concrete characterized by its high strength, high durability, and high stiffness. Autogenously shrinkage represents one of the issues of UHPC that occurred at early ages. It occurs particularly during the first 48 hours after casting. This paper focuses on the ways that can be depended on to mitigate the autogenously shrinkage and obtain the outstanding mechanical properties of UHPC. The results showed that the use of coarse sand and high dose of high range water reduced the admixture above 5% of cementations of materials weight, and high ambient temperature at the time of mixing and casting led to increasing the autogenously shrinkage. While using fine sand, silica fume at 25% of cement weight, and crushed ice at 50% of mixing water to control the mixing temperature can reduce autogenously shrinkage significantly.
The religious endowments are one of the important sources, which acquire historical, cultural, and economic importance in all countries of the world. In particular, a religious endowment in Iraq includes several distributed real estates and lands that usually require efficient management systems. One of the most important factors affecting the management of real estates that belong to religious endowments is the rental amount of each real estate. In general, the estimation of the rental of real estates can support the future development of religious endowments. Governmental agencies are faced with some challenges in the management of religious endowments in terms of rental pricing due to numerous economic and geographic factors. The rapid development of artificial intelligence systems and Geomatic techniques can present a framework for rental amount estimation based on spatial and non-spatial factors. In this study, a machine learning algorithm (Support Vector Regression) will be combined with Geographic Information System (GIS) to predict and evaluate the rental amount of real estates that belong to a religious institution in Iraq (Shiite endowment in Hillah city). The final results indicated that the proposed method achieved an overall accuracy of 71%, a root mean square error of 0.2257 million Iraq, Dinar (IQD), and a correlation coefficient of 0.9272. This study can be used as an effective tool for the decision-makers to plan and manage the religious endowments in developing countries.
In the presented study, a WorldView2 WV2 satellite image has been prepared to be used in map updating projects. The performed operations can be classified into two categories, the first category includes pansharpening methods for creating a new 8- spectral bands of WV2 Imagery, each one of them has a 0.5-meter spatial resolution. The Pansharpening technique has been implemented with four different approaches, i.e. (Principal Components PC, Wavelet Transform WT, Hyperspherical Color Space HCS, and High Pass Filtering HPF). For these four methods and based on a visual comparison among the quality of the resulting images (with respect to the original Multi-spectral Worldview2 MS-WV2 image), the HCS image has been determined as the best one of them. Because of the high-security situation of the study area, and the impossibility of using the Global Positioning System GPS and other surveying devices there, the Controlled Image Based CIB of 1-meter resolution has been depended on as a source of reference Ground Control Points GCPs. Initially, set GCPs and Check Points are determined on both the HCS Pansharpened image and the CIB image. For maintaining the linearity of the geometric distortion within WV2 original image, the 1st order polynomial transformation model has been selected to perform the geometric correction process. It is clearly concluded that the resulted Root Mean Square Error RMSE of the geometric correction process is acceptable for a wide range of mapping applications. Moreover, the resulting geometrically corrected pan-sharpened WV2 image can be utilized for increasing the interpretation capability of the land features by giving more false color displaying options, and finally supporting the related map updating projects.
The great economic development and the growth of modern means of construction have led to the spread of large quantities of chemical admixtures that we must be cautious of. As the world is turning towards environmentally friendly alternatives, finding locally viable solutions is becoming inevitable. The influence of using Nano starches of a biopolymer on certain properties of silica fume concrete in the fresh case (slump and fresh density) and in the hardened case (compressive strength, splitting tensile strength, and flexural strength) has been investigated. It has been added to silica fume concrete in various percentages of (0%, 0.25%, 0.5%, and 0.75%) by cement weight. The mix proportions of concrete mixtures were 1:2.3:2.3, with a fixed w/c of 0.47 and 15 % silica fume added by the weight of cement for all mixers. super plasticizer of 0.75% is also added by the weight of cement for all mixtures. According to the findings, slump increased by 19%, and fresh density increased by 3% when Nano starch was added at a concentration of 0.75%. The optimal level of Nano starch addition was 0.25%, which resulted in a 43% increase in compressive strength and a 34% and 26% increase in splitting tensile and flexural strength of concrete, respectively.
Multifunctional Cementitious Composite (MCC) characteristics are directly related to the type and dosage of the Electrically Conductive Materials (ECMs) reinforcing the relevant concrete matrices. This study investigated the electro-mechanical capacities of fiber reinforced concrete pavement (FRCP) with and without the addition of micro scale-carbon fiber (CF). The impact energy of FRCP under compacted load was evaluated initially; then, the effects of 0.5% and 1% content by volume of CF on the piezoresistivity capacities of FRCP were investigated under applied impact load. This type of load is the most common force causing long-term rigid pavement deterioration. Obtained results showed that the use of a hybrid fiber (micro-scale carbon fiber 0.5% and macro-scale steel fiber 1% by volume) enhanced the impact strength (impact energy) due to CF’s resistance to micro-cracks. The developed FRCP showed good results in terms of self-sensing under compact load with both 0.5 and 1.0% by volume of CF.
Reinforcement interlayer reduces the development of cracks in the asphalt overlay by absorbing the stresses induced by heavy traffic or underlying cracking in the early-constructed pavement. This research is dedicated to studying the behavior of pavement layers on a sand subgrade under simulated effect of earthquake. In this study, the sand layer has a thickness of 600 mm and the base course is taken as 300 mm. The asphalt layer was prepared as a panel with dimensions of 300 × 300 × 50, which represents the surface layer. These layers are experimentally tested under the influence of earthquake loading with different frequencies 0.5, 1, 1.5 Hz. The tests consist of two parts without adding the geogrid, with geogrid in the center of the base layer and between the base layer and sand layer. Loaded stresses in the three layers are monitored using stress gauge sensors, while displacements of the asphalt layer by using displacement gauge sensor. Obtained results considered models reinforced with geogrid, the stress recorded is higher than in unreinforced models but the displacement decreases by increasing the geogrid in the layers at three frequencies. When the geogrid is laid between the base course and sand layer, the stress in the sand subgrade layer is less than that in the base and asphalt layers.
Wavelet analysis has become a powerful tool for denoising images. It represents a new way to achieve better noise reduction and increased contrast. Here, experimentally demonstrate the abilities of the discrete wavelet transform with Daubechies basis functions for improving the quality of noisy images. In this research, two methods have been compared to modify the coefficients using a soft and hard threshold to improve the visual fineness of noisy images depending on the Root-Mean-Square error (RMS). The low RMS value and better noise reduction are found in the soft threshold methods based on Daubechies wavelet (db8) for the first image RMS=0.101 and the second example RMS=0.109.