Engineering and Technology Journal

Development of Intensity-Duration-Frequency (IDF) Models for Manually Operated Rain Gauge Catchment: A Case Study of Port Harcourt Metropolis Using 50years Rainfall Data

Francis J. Ogbozige

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 627-635
DOI: 10.30684/etj.2021.131839.1064

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.

3D Numerical modeling of Soft soil Improved by Rigid Inclusions Supported an Embankment

MESSIOUD Salah; NEGHMOUCHE Yassamina

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 636-648
DOI: 10.30684/etj.2021.132023.1083

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.

Monitoring Soil Degradation in The Mesopotamian Plain Using GIS and Remote sensing Techniques

Abdulrazak T. Ziboon; Muthanna M. Albayati; Fadhaa T. Dalhel

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 649-660
DOI: 10.30684/etj.v40i5.2121

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).

Finite Element Simulation of Repeated Loading Test of Asphalt Concrete

Noor S. Hatem; Miami M. Hilal; Mohammed Y. Fattah

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 661-667
DOI: 10.30684/etj.v40i5.2128

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.

Push–out Test of Timber Concrete Composite Construction

Ihab S. Saleh; Nabeel A. Jasim; Anis A. Mohhamed Ali

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 668-676
DOI: 10.30684/etj.v40i2.2175

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.

SWOT-Based Assessment of the Maintenance Management of the Wastewater Treatment Plants in Iraq

Reem Tareq Al-Attar; Faris H. Al-Ani; Mahmoud Saleh Al-Khafaji

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 677-694
DOI: 10.30684/etj.v40i5.2146

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.

Assessment of Future Climate Change Impacts on Water Resources of Khabour River Catchment, North Of Iraq

Lena Haitham; Mustafa Al-Mukhtar

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 695-709
DOI: 10.30684/etj.v40i5.1925

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.

Effect of Partial Saturation on Ultimate Bearing Capacity of Skirted Foundations

Mahmood R. Mahmood; Saad F. A. Al-Wakel; Muthana S. Mohammed

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 710-721
DOI: 10.30684/etj.v40i5.2259

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.

Modeling Critical Gap of Al Turkmani Roundabout in Baghdad City

Laith Q. Shadhan; Zainab A. Alkaissi

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 722-731
DOI: 10.30684/etj.v40i5.1628

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.

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Issue 5

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