Issue 5
Research Paper
Francis J. Ogbozige
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.
MESSIOUD Salah; NEGHMOUCHE Yassamina
Abstract
A three-dimensional finite element model suggested to determine the settlements and stresses of an embankment placed on soft soil reinforced by rigid inclusions. To make it simple the layers of soil and the embankment are supposed to be horizontal in a semi-infinite medium and the base of the soft soil is supposed to be rigid (bedrock). The interacting elements of the model are supposed to be elastic. The determination of the behavior of the soil-inclusions-embankment system was realized according to the construction phases of the embankment layers. The settlements and stresses were calculated according to construction phases of the embankment layers. At the end of each calculation phase, the stress field and the displacement field are extracted. The values are then introduced into the model the beginning of the next phase. The obtained results are presented in terms of the (settlement) vertical displacements and vertical stresses for the elementary cell and the global model respectively. This study allows the observation of three-dimensional interactions; the mechanisms of load transfer and the interaction between the different zones of the embankment. The numerical calculations are much lower than those measured in situ. A verification calculation on the stresses transmitted by the rigid inclusion shows that only 90% of the total load is applied with the numerical calculation.
Abdulrazak T. Ziboon; Muthanna M. Albayati; Fadhaa T. Dalhel
In the present work , various remote sensing techniques have been used to investigate soil degradation in Iraq (The Mesopotamian plain) for the period (1976 - 2021) using different research and data like satellite image such as (Landsat 1-5 MSS 1976 , Landsat 4-5 TM C1 Level-1 1996, Landsat 8 2016 and sentinel-2 2021 ) , using different Program and software (ENVI 5.3 which extract data from image satellite by using TCT , EMI and NDVI indicators , Eras image 2015 use to subset area of interest ,layer stack and merge resolution , Arc GIS 10.7 use to make database and maps production ),the article use some of filters and indicators , Normalized Difference Vegetation Index (NDVI), Elian Mapping Index (EMI), Tasseled Cap Transformation (TCT) to extract a set of indicators (area of vegetation cover (NDVI), soil erosion index (EMI) , classification of wet and dry soils, and water cover calculation (TCT), the article will be calculate the areas accurately to know the type and causes of degradation by comparing those lands with past years by observing them with satellites for different years (advanced remote sensing techniques).
Noor S. Hatem; Miami M. Hilal; Mohammed Y. Fattah
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.
Ihab S. Saleh; Nabeel A. Jasim; Anis A. Mohhamed Ali
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.
Reem Tareq Al-Attar; Faris H. Al-Ani; Mahmoud Saleh Al-Khafaji
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.
Lena Haitham; Mustafa Al-Mukhtar
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.
Mahmood R. Mahmood; Saad F. A. Al-Wakel; Muthana S. Mohammed
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.
Laith Q. Shadhan; Zainab A. Alkaissi
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.
Mustafa H. Al-Helaly; Imzahim A. Alwan; Amjed N. AL-Hameedawi
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.
Review Paper
Adil M. Jabbar; Mohammed J. Hamood; Dhiyaa H. Mohammed
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.
Research Paper
Basil S. Al-Shathr; Haider A. Abdulhameed; mohammed M. Mahdi
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.
Hind Akram; Miami Hilal; Mohammed Fattah
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℃.
Hussain Muhamed; Mustafa N. Hamoodi; Abd Alrazzak T. Ziboon
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.
Qasim A. Al-Obaidi; Makki K. Mohsen; Ayad O. Asker
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.
Hasan H. Joni; Mustafa H. Jasim
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.
Nadeem Salam; Wasan I. Khalil
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.
Ali A. Ali; Tareq S. Al-Attar; Waleed A. Abbas
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 (SiO
2/Al
2O
3) 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.
Alaa R. Al-Obaidi; Riyad H. Al-Anbari; maan S. hassan
The possibility of saving and sustaining natural materials by reusing waste is one of the most important goals researchers seek to achieve and prove its effectiveness and positive impact on the environment. In this study, domestic wastewater sludge was utilized in concrete production as partial cement changing with different ratios (0, 5, 10, and 15) % with dry sludge. The study showed that the compressive strength test showed that the partial replacement of cement by dry sludge caused reduction increased directly with the increase of sludge ratio compared with concrete reference specimens. The study found that dry sludge can be used up to 15% as a replacement in concrete sidewalks and roads because these applications use horizontal construction, which does not require the same high strength resistance as vertical construction. In addition, it was also found that using up to 10% dry sludge content in concrete may positively impact reducing sludge levels in the environment and the cost of cement production without a significant effect on the compressive and flexural strength of concrete. The study aimed to encourage government agencies and the business sector to employ excess quantities of domestic sludge in the construction industry, as well as to investigate the influence of partial replacement of cement with dry sludge on the compressive strength of concrete.
