| 61. |
- Al Amli, Ali Sabah, et al.
(författare)
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Numerical simulation of behaviour of reinforced concrete bars in saturated soil using theoretical models
- 2020
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Ingår i: Journal of Engineering Science and Technology. - Malaysia : School of Engineering. Taylor’s University. - 1823-4690. ; 15:1, s. 392-405
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a nonlinear analysis for square reinforced concrete (RC) foundation slab with bars used with both unsaturated and saturated soils in order to investigate, which response is affected by loading. Different parametric studies are undertaken in this study to determine the effect of load-displacement relationships for RC member or foundation with different cases such as (the distance of bars, diameters of bars reinforcement, types of reinforcement bars steel bars and geogrid reinforcement, yield stress for reinforcement and modulus of elasticity with compressive strength for concrete). A finite element model by ABAQUS software program is used to predict the load versus vertical displacement response of the tested RC foundations with soil by using other researchers´ experimental results. The present finite element models account for the constituent load-displacement behaviour between the RC foundations with soil and the effective load. The numerical results were compared with the experimental results obtained from other research, and good correlations were obtained. The models developed in this study can accurately capture the behaviour and predict the load-displacement of RC foundation with soil. This study shows that geogrid reinforcement enhanced the capacity of the foundation or member when used with different ratios of steel bars in soil and this provides a sustainable solution by reducing steel reinforcement. This geogrid ratio the reinforcement, while the member in saturated soilis less strong than it when in unsaturated soil.
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| 62. |
- Al Amli, Ali Sabah, et al.
(författare)
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Seismic Behavior of Reinforced Normal Strength Concrete and Reactive powder Concrete Eccentrically Loaded Frames
- 2020
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Ingår i: Technology Reports of Kansai University. - Japan : Faculty of Engineering, Kansai University. - 0453-2198. ; 62:3, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this investigation is to study the effect of repeated load on reinforced concrete beam-column connections. Eight specimens were adopted in this investigation; four specimens were poured with normal strength concrete, and other four specimens were poured with reactive powder concrete. The frames dimensions are constant; 280 mm and 200mm of beam height and width respectively with 1000mm beam length and 200mm square column with 700mm height. The load was applied at mid-span and at a distance 150mm from the mid-span of beam. The reduction in frame capacity reached to 53.3% due to eccentricity. All tested specimens were failed at cycle 5 with different load level; . the decrease in stiffness of cyclically loaded frames of normal strength concrete was higher than that of reactive powder concrete frames. The deflections of cyclically loaded frames higher than that of statically loaded frames. In brief, the frames with eccentrically and cyclically loading give lowest ultimate strength, first crack load and stiffness with highest deflections.
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| 63. |
- Al-Ani, Ibrahim Abdulrazak, et al.
(författare)
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Development of Lightweight Concrete Using Industrial Waste Palm Oil Clinker
- 2020
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Ingår i: Journal of Civil Engineering and Architecture. - USA : David Publishing Company. - 1934-7359 .- 1934-7367. ; 14:6, s. 293-307
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Tidskriftsartikel (refereegranskat)abstract
- Concrete is a major material used in the construction of buildings and structures in the world. Gravel and sand are the major ingredients of concrete but are non-renewable natural materials. Therefore, the utilisation of palm oil clinker (POC), a solid waste generated from palm oil industry is proposed to replace natural aggregate in this research to reduce the demand for natural aggregates. One mix of ordinary concrete as control concrete; while four mix proportions of oil palm clinker concrete were obtained by replacing 25%, 50%, 75%, and 100% of gravel and sand of control concrete with coarse and fine oil palm clinker respectively by volume, with same cement content and water cement ratio. Compressive strength test was carried out of concretes with different percentages of oil palm clinker; whereas water absorption tests according to respective standard, were carried out to determine the durability properties of various mixes. Based on the results obtained, the study on the effect of percentage of clinker on strength and durability properties was drawn. According to ACI classification of light weight concrete only the 100 percentage replacement can achieve the definition of light weight concrete since its density is less than 1,900 kg/m3 and strength larger than 17 MPa. Eventually the 25% replacement of the normal aggregate by the OPC will improve the strength and durability of the concrete.
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| 64. |
- Al-Ani, Ibrahim Abdulrazak, et al.
(författare)
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Multi criteria decision making to optimize the best runoff control measures for the Haditha Dam Reservoir, Iraq
- 2020
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Ingår i: Journal of Environmental Hydrology. - : International Association for Environmental Hydrology. - 1058-3912 .- 1996-7918. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- In Iraq, the two dominating surface water sources are Tigris and Euphrates Rivers in which some dams constructed on both of them forming reservoirs. The Haditha Dam reservoir is one of the most essential sources of drinking, irrigation, flood control and hydropower generation in Anbar State, Western Iraq. Besides, the reservoir is a unique habitat with a wide spectrum of biodiversity. The objective of this study is to investigate and monitor the water quality in Haditha Dam reservoir and introduce Multi Criteria Analysis (MCA) as a means to highlight the best runoff control measures depending on selected criteria and criteria weights. Experts were interviewed for the selection of criteria and for the assignment of the weight factor and scores. Four criteria from three categories such as technical, economic and environmental aspects were selected. Results from this study indicated that a the difference in TSS and Turbidity between the dry and wet seasons necessitates the installation of runoff control measures. It was found that the soil binders, sediment basin and diversion channel are the best alternatives for controlling erosion, sediment and drainage respectively. The sensitivity analysis showed very strong decisions made by the experts for the technical, economic and environmental criteria.
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| 65. |
- Al-Ansari, Nadhir, 1947-
(författare)
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Can we restore the Marches in Iraq (Garden of Eden)?
- 2020
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Ingår i: Engineering. - USA : Scientific Research Publishing. - 1947-3931 .- 1947-394X. ; 12:7, s. 466-486
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Tidskriftsartikel (refereegranskat)abstract
- Iraqi marshes are located within the southern part of Iraq where the Tigris and Euphrates Rivers join. There are three main marshes (Hammar Central and Hawizeh). They used to cover an area 15,000 - 20,000 square kilometers. The government of Iraq started to dry the marshes since 1990 for military reasons. Oil companies started to work in that area, and they occupied about 25% of that area. After 2003, the government changed, and they started to restore the remainder 75% of marshes. To achieve this goal, they require about 13 billion cubic kilometers of water (BCM). The problem was the scarcity of water due to the building of dams in riparian countries and climate change. It is believed that if the government follows a prudent water resources strategy, then it will be possible to restore the marshes.
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| 66. |
- Al-Ansari, Nadhir, 1947-, et al.
(författare)
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Hydrogeology of the Mesopotamian Plain : A Critical Review
- 2020
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - UK : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 10:4, s. 111-124
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Tidskriftsartikel (refereegranskat)abstract
- The Mesopotamian Plain hydrogeologically is a semi-closed basin where most of the groundwater accumulates in the central and southern parts of the plain. However, small part of the groundwater flows out of the basin to the Gulf. This special character has significant effects on the depth and type of the groundwater in the plain. The depth ranges from (<10 – 100)m; however, the depth in the most of the plain ranges from (10 – 20)m. The type of the ground water is mainly salty water with concentrations of (10,000 – 50,000) mg/l; however, in the central part it is even Brine water (> 500,000 mg/l). No fresh groundwater exists in the plain.
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| 67. |
- Al-Ansari, Nadhir, 1947-, et al.
(författare)
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Mosul Dam : Is it the Most Dangerous Dam in the World?
- 2020
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Ingår i: Geotechnical and Geological Engineering. - Switzerland : Springer. - 0960-3182 .- 1573-1529. ; 38, s. 5179-5199
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Tidskriftsartikel (refereegranskat)abstract
- Mosul Dam is an earth fill dam, with a storage capacity of 11.11 km3 constructed on highly karstified gypsum beds alternating with marl and limestone. After impounding in 1986, seepage locations were recognized. The dam situation now indicates that it is in a state of extreme relative risk. If it fails, then 6 million people will be affected and 7202 km2 area will be flooded. Grouting operations will elongate the life of the dam but will not solve the problem. Building a protection dam downstream will be the best measures to secure the safety of the downstream area and its’ population.
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| 68. |
- Al-Douri, Yamur K., et al.
(författare)
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Risk-based life cycle cost analysis using a two-level multi-objective genetic algorithm
- 2020
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Ingår i: International journal of computer integrated manufacturing (Print). - : Taylor & Francis. - 0951-192X .- 1362-3052. ; 33:10-11, s. 1076-1088
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study has been to develop a two-level multi-objective genetic algorithm (MOGA) to optimize risk-based LCC analysis to find the optimal maintenance replacement time for road tunnel ventilation fans. Level 1 uses a MOGA based on a financial risk model to provide different risk percentages, while level 2 uses a MOGA based on an LCC model to estimate the optimal fan replacement time. Our method is compared with the approach of using a risk-based LCC model. The results are promising, showing that the risk-based LCC offers the possibility of significantly reducing the maintenance costs of the ventilation system by optimising the replacement schedule by considering the risk costs. The risk-based LCC can be used with repairable components, making it applicable, useful and implementable within Swedish Transport Administration (Trafikverket). In this study, MOGA operators have selected the cost of maintenance and risk data through the previous levels using different ways to provide different possible solutions. A drawback of the MOGA based on a risk-based LCC model with regard to its estimation is that a late replacement period over 20-year period might increase the maintenance cost. Therefore, the MOGA does not provide a good solution for a risk-based LCC.
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| 69. |
- Al-Jabban, Wathiq, et al.
(författare)
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Briefing : Common laboratory procedures to prepare and cure stabilised soil specimens: a short review
- 2020
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Ingår i: Geotechnical Research. - UK : Institution of Civil Engineers (ICE). - 2052-6156. ; 7:1, s. 3-10
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Forskningsöversikt (refereegranskat)abstract
- Soil stabilisation is used extensively to improve the physical and mechanical properties of soils to achieve the desired strength and durability properties. During the design process, laboratory investigation is conducted firstly to obtain an enhancement in soil strength and stiffness, in addition to the type and amount of binder required. The methods of preparing and curing specimens of soil–binder mixtures directly influence the properties of the stabilised soils. The most common laboratory protocols used for preparing and curing the specimens of stabilised soil are presented in this short review. The review focuses on several aspects such as homogenisation of the natural soil, mixing type and duration, mould type, moulding techniques and curing time and condition. This review can assist various construction projects that deal with soil improvement to choose an appropriate method for preparing and curing a soil–binder mixture to simulate the field conditions as much as possible and obtain uniform soil–binder mixtures.
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| 70. |
- Al-Janabi, Ahmed Mohammed Sami, et al.
(författare)
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Experimental and Numerical Analysis for Earth-Fill Dam Seepage
- 2020
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Ingår i: Sustainability. - Switzerland : MDPI. - 2071-1050. ; 12:6, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Earth-fill dams are the most common types of dam and the most economical choice. However, they are more vulnerable to internal erosion and piping due to seepage problems that are the main causes of dam failure. In this study, the seepage through earth-fill dams was investigated using physical, mathematical, and numerical models. Results from the three methods revealed that both mathematical calculations using L. Casagrande solutions and the SEEP /Wnumerical model have a plotted seepage line compatible with the observed seepage line in the physical model. However,when the seepage flow intersected the downstream slope and when piping took place, the use of SEEP /Wto calculate the flow rate became useless as it was unable to calculate the volume of water flow in pipes. This was revealed by the big dierence in results between physical and numerical models in the first physical model, while the results were compatible in the second physical model when the seepage line stayed within the body of the dam and low compacted soil was adopted. Seepage analysis for seven dierent configurations of an earth-fill dam was conducted using the SEEP /W model at normal and maximum water levels to find the most appropriate configuration among them. The seven dam configurations consisted of four homogenous dams and three zoned dams. Seepage analysis revealed that if sucient quantity of silty sand soil is available around the proposed dam location, a homogenous earth-fill dam with a medium drain length of 0.5 m thickness is the best design configuration. Otherwise, a zoned earth-fill dam with a central core and 1:0.5 Horizontal to Vertical ratio (H:V) is preferred.
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