Journal of Engineering

Residential complexes have witnessed a great demand in most countries worldwide, as they are one of the main infrastructure elements, in addition to achieving a developed urban landscape. However, complex residential projects in developing countries face various factors that could be improved in their implementation, especially in Iraq. Sixty-two experts in residential complex projects were interviewed and surveyed to verify these projects' failure factors,. Fifty-one factors were the main failure factors, divided into four main components (leadership, management system, external forces, and project resources). The Relatively Important Index (RII) is used to determine the relative importance factors and obtain the top twelve factors that cause the optimal failure factors, correspondingly: political interference (87.7%), change in governments (86.5%), partisan politics available (85.6%), Unclear strategic planning (84.3%), inadequate planning (84.3%), lack of materials and equipment (83.3%), the poor obligation for project leaders (82.6%), work suspension due to demonstrations (82.3%), lack of human capacity (81.8%), bureaucracy (81.7%), corruption (81.4%), and misalignment in culture or ethics (81.3%). The achieved RII readings were high for leadership (73.1%), followed by project resources (71.3%), management systems (70.5%), and external forces (69.9%). The study recommended addressing the problems of implementing complex residential projects and solving the crisis to start the state's economic growth phase according to new foundations and standards.

Water quality planning relies on Biochemical Oxygen Demand BOD. BOD testing takes five days. The Particle Swarm Optimization (PSO) is increasingly used for water resource forecasting. This work designed a PSO technique for estimating everyday BOD at Al-Rustumiya wastewater treatment facility inlet. Al-Rustumiya wastewater treatment plant provided 702 plant-scale data sets during 2012-2022. The PSO model uses the daily data of the water quality parameters, including chemical oxygen demand (COD), chloride (Cl-), suspended solid (SS), total dissolved solids (TDS), and pH, to determine how each variable affects the daily incoming BOD. PSO and multiple linear regression (MLR) findings are compared, and their performance is evaluated using mean square error, relative absolute mistake, and coefficient of determination. PSO utilised COD, TDS, SS, pH, and Cl- as inputs, generating a mean square error of 1029.10, an average absolute relative error of 9.41%, and a coefficient of determination of 0.89. Comparisons demonstrated that the PSO model could accurately calculate the daily BOD at Al-Rustumiya wastewater treatment plant\'s inlet.

Currentnumerical research was devoted to investigating the effect of castellated steel beams without and with strengthening. The composite concrete asymmetrical double hot rolled steel channels bolted back to back to obtain a built-up I-shape form are used in this study. The top half part of the steel is smaller than the bottom half part, and the two parts were connected by bolting and welding. The ABAQUS/2019 program employed the same length and conditions of loading for four models: The first model is the reference without castellated and strengthening; the second model was castellated without strengthened; the third model was castellated and strengthened with reactive powder concrete encased in the steel web, and the fourth model was castellated and strengthenedwith reactive powder concrete and lacing steel rebar\\'s welded diagonally on two sides of the steel web. According to the Numerical results, there was an increase in ultimate load capacity compared to the reference model of about 22.74%, 51.65%, and 77.98%in the second, third, and fourth models, respectively; also, there is a reduction in deflection of 55.52%, 58.74, and 60.55% in the second, third, and fourth models, respectively, compared to the level deflection at ultimate load for the reference model, with an increase in stiffness and ductility.In comparison to the I section, the fabrication of a castellated steel beam from the double channel is more cost-effective in terms of cutting steelloss at the ends of the castellated beam, this is due to the feature ofrotation and reflection of the steel channel section during cutting and forming to castellated shape.

Organic soil is problematic soils in geotechnical engineering due to its properties, as it is characterized by high compressibility and low bearing capacity. Therefore, several geotechnical techniques tried to stabilize and improve this soil type. In this study, sodium silicate was used to stabilize sand dune columns. The best sodium silicate concentration (9%) was used, and the stabilized sand dune columns were cured for seven days. The results for this soil were extracted using a numerical analysis program (Plaxis 3D, 2020).In the case of studying the effect of (L/D)(where ‘’L” and ‘’D’’ length and diameter of sand dune columns) of a single column of sand dunes stabilized with sodium silicate with a different diameter, the results showed that the best effect was for L/D of (4) with D equal to (0.7m) in the end bearingcolumns type. In the case of studying a group of columns,the percentage of improvement in soil bearing ratio increased with increasing the number of columns in both floating and end bearing types.When using (8-columns) with a square distribution pattern, the optimum improvement was at the end bearing and at the ratio L/D of (6), where the improvement percentage was (666%) compared to the unimproved soil.

This study delves into the realm of advanced cooling techniques by examining the performance of a two-stage parallel flow indirect evaporative cooling system enhanced with aspen pads in the challenging climate of Baghdad. The objective was to achieve average air dry bulb temperatures (43 oC) below the ambient wet bulb temperatures (24.95 oC) with an average relative humidity of 23%, aiming for unparalleled cooling efficiency. The research experiment was carried out in the urban environment of Baghdad, characterized by high temperature conditions. The investigation focused on the potential of the two-stage parallel flow setup, combined with the cooling capability of aspen pads, to surpass the limitations imposed by conventional cooling methods. The empirical findings underscored the capacity of the two-stage parallel flow configuration to achieve air-dry bulb temperatures surpassing the ambient wet bulb temperature.Nonetheless, it was evident that an excessive application of water (exceeding 9lpm) onto the aspen pads within the wet channels yielded adverse repercussions on the cooler's performance metrics, specifically in terms of wet bulb effectiveness and coefficient of performance. A range of air flows spanning from 150 CMH to 350 CMH was analyzed, revealing the influence of heightened air flow rates on the resultant dry bulb temperatures delivered by the cooling system. Notably, the peak wet-bulb effectiveness registered at 1.08, concurrently yielding a coefficient of performance measuring 7.8.

Building Information Modeling (BIM) is extensively used in the construction industry due to its benefits throughout the Project Life Cycle (PLC). BIM cansimulate buildings throughout PLC, detect and resolve problems, and improve building visualization that contributes to the representation of actual project details inthe construction stage. BIM contributes to project management promotion by detecting problems that lead to conflicts, cost overruns, and time delays. This work aims to implement an effective BIMfor the Iraqi construction projects’ life cycle.The methodology used is a literature review to collect the most important factors contributingto the success of BIM implementation, interview the team of the Central Bank of Iraq (CBI) building, and strive to improve the BEP of the CBI building. However,previous studies indicate collaborative work and communications enhance effective BIM implementation, which can improve BIM use by applying a BEP and an AEC (UK) BIM protocol that leads to positive BIM impact. BEP comprises important information and goals related to the intended project, includingthe BIM collaborative process (process map), information exchange requirements, BIM data management, BIM model management, and quality control, which are considered essential for enhancing BIM collaboration during PLC. This paper concludes that implementing BIM effectively requires overcoming obstacles faced by Iraqi construction projects. Effective BIM implementation requires improving cooperation and communication throughout the construction process, which could be achieved by depending on the BIM Execution Planning Guide(BEP Guide) and the AEC (UK) BIM Protocol 2012 V2.0.

Rutting is a crucial element of the mechanical performance characteristics of asphalt mixtures, which was the primary target of this study. The task involved substituting various portions of virgin coarse aggregate with recycled concrete aggregate materials that had been treated or left untreated at rates ranging from 25to 100%, with a constant increase of 25%. The treatment process of recycled concrete aggregate involved soaking in acetic acid, followed by a mechanical process for a short time inside a Los Angeles machine without the balls. This research utilizedtwo primary tests: the standard Marshall test to identify the optimal asphalt contents and the volumetric characteristics of asphalt mixtures. The other one was the wheel tracking test, which involved manufacturing 11slabs with a dimension of 30 x 40 × 5 cm and testing them under repeated wheel loadsof 700 N at 55°C to investigate rutting resistance. The results demonstrate that using RCA had a negative impact on rutting resistance, where rut depth increased by 21.64% when using 100% pre-soaked treated RCA.

With the increase in industry and industrial products, quantities of waste have increased worldwide, especially plastic waste, as plastic pollution is considered one of the wastes of the modern era that threatens the environment and living organisms. On this basis, a solution must be found to use this waste and recycle it safely so that it does not threaten the environment. Therefore, this research used plastic wasteas an improvement material for clay soil.In this research, two types of tests were conducted, the first of which was a laboratory test, where the undrainedshear strength (cohesion), compression index(Cc), and swelling index(Cr) of the improved and unimproved soils werecalculated(plastic was added in proportions (0.5, 1, 1.5, 2)%. The second part of the examinationwas done through physical modeling, where 2% of plastic was used, considered the optimal percentage in this research, and the calculation of the carrying capacity-settlement relationship for both the improved and unimproved soils. Using this percentage of plastic showed an improvement in the relationship between the bearing capacities of soil vs. subsidence, as an increase in the amount of stress was observed from 405KPa to 459 kPa at 10% of subsidence.

The public procurement crisis in Iraq plays a fundamental role in the delay in the implementation of construction projects at different stages of project bidding (pre, during, and after). The procurement system of any country plays an important role in economic growth and revival. The paper aims to use the fuzzy logic inference model to predict the impact of the public procurement crisis (relative importance index and Likert scale) was carried out at the beginning to determine the most important parameters that affect construction projects, the fuzzy analytical hierarchy process (FAHP) to set up, and finally, the fuzzy decision maker's (FDM) verification of the parameter for comparison with reality. Sixty-five construction projects in Iraq have been selected, and the most crucial crisis variables were used for calculating the weights and their importance, using the fuzzy logic inference model to verify the crisis parameters and the extent of their impact in preparation for predicting the mathematical model of public procurement parameters. After the algorithm had been completed, it was noted that the fast, messy genetic algorithm produced a little difference between training and testing (0.012% and 0.0057%), which is more reliable for predicting mean results from models. The paper’s major conclusion is that 18 crisis factors in public procurement through different stages affect construction projects in Iraq.

This workevaluates the economic feasibility of various production scenarios for the Zubair reservoir in the Kifl oil field using cash flow and net present value (NPV) calculations. The Kifl field is an exploratory field that has not yet been developed or assessed economically. The first well was drilled in 1960, and three other wells were later drilled to assess the oil accumulation, so in this research, Different production scenarios were evaluated economically.These scenarios were proposed based on the reservoirmodel of the Zubair formation in the field. The research methodology used QUE$TOR software to estimate capital expenditures (CapEx) and operating expenditures (OpEx) based on field-level data, production profiles for each scenario, and produced fluid properties. CapEx estimates were mainly based on the number of drilled wells and plateau duration, while OpEx estimates were based on the number of barrels produced from each scenario. Cash flow values were estimated each year in the production interval after subtracting water handling costs, CapEx, and OpEx from the gross revenue of oil produced. The NPV for each scenario was then calculated using a 5% interest rate, and the most economical option was determined by comparing the NPV values of each scenario. Case-3 scenario was identified as the most economical option, with a high NPV value of approximately 612 MM$, an oil production rate of 10 MSTB/d, a Plateau duration of 3 years, a total number of wells of 11, and an Initial water cut of 13 %.

The construction industry plays a crucial role in the countries' economy, especially in the developed country. This point encourages the concerned institution to use new techniques and integrate many techniques and methods to maximize the benefits. The main objective of this research is to evaluate the use of risk management, value management, and building information modeling in the Iraqi construction industry. The evaluation process aims at two objectives. The direct objective was to evaluate the knowledge inrisk management (RM), value management (VM), and building information modeling (BIM). The indirect objective was to support the participants with information related to the main items mentioned. The questionnaire survey was used as a data collection method. The participants in the survey were engineers from the Iraqi construction sector. The sample size was 121 engineers from 34 institutions with multidisciplinary backgrounds. The results showed that the engineers need to develop the training system and merge many methods and techniques in their institution to maximize the benefits using an integration model capable of dealing with the variable environment in construction, especially in developing countries like Iraq.

Oilwell cementing operations are crucial for drilling and completion, preserving the well's productive life. However, weak and permeable formations pose a high risk of cement slurry loss, leading to failure. Lightweight cement, like foamed cement, is used to avoid these difficulties. This study is focused on creating a range of foamed slurry densities and examining the effect of gas concentration on their rheological properties. The foaming agent and foam stabilizer are tested, and the optimal concentration is determined to be 2% and 0.12%, respectively, by the weight of the cement.


Furthermore, the construction of samples of foam cement with different densities (0.8, 1.0, 1.2, 1.4, and 1.6) g/cc is performed to find the relation with different volumetric percentage gas in foamed cement slurry (57.5, 47, 36, 25.5, and 15%). The relationship between rheological properties and foam quality is discussed, as the presence of gas plays a significant role in enhancing rheological properties. The rheology of foam cement increases proportionally with increasing foam quality, especially the plastic viscosity, which is 26 cp at 0% foam quality and 50 and 65 cp at 15% and 57.5% foam quality, respectively. Also, yield points increase as foam quality improves. Therefore, it is feasible to exclude certain cement additives that increase viscosity.