Ph.D. in Civil Engineering/ Structures

Professor in structural engineering. Many publications concerning reinforced concrete strengthening and optimizations.

Evaluation of Ultra-High-Performance Fiber-Impregnated Reinforced Concrete Beam Elements

Journal Scientific Research Journal of Multidisciplinary

publisher AIR Consortium

DOI 10.47310/srjmd.2024.v04.i02.012

Issue 2

Volume 4

Ultra-High- Performance- Fiber Reinforced -Concrete (U-H-P-FR-C) seismic elements are constructed very differently from traditional concrete. However, as the U-H-P-FR-C seismic members are expensive, much information in the literature about how they behave dynamically. The requirements for the experimental work (design guidelines for large-scale seismic elements) can be reduced using limited element programs. Analytical models, which validated can be employee to examine the modifications in geometry, loading configurations, and reinforcement ratios, which will affect seismic behavior. For simulating the U-H-P-FR-C beam under dynamic stress and evaluate the numerical model's prediction precision, this study used a restricted element program, ABAQUS. Tensile and uniaxial pressure tests have used to establish the parameters of the material model. The results obtained from the numerical models show that the dynamic behavior of U-H-P-FR-C beams can be well predicted by the analytical model.

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Optimal design of public transport networks (lines) in Kirkuk City using GIS-based AHP

Journal AIP Conference Proceedings

publisher AIP.org

DOI https://doi.org/10.1063/5.0238436

Issue 1

Volume 3249

This study developed an approach for creating the best possible Bus Rapid Transit (BRT) system in Kirkuk City, Iraq, by combining the Analytical Hierarchy Process (AHP) with Geographic Information System (GIS) modeling. The main goals are survey data collecting to determine transportation requirements, GIS modeling to assess possible BRT route alignments, route prioritizing based on AHP, and geographic analysis to identify appropriate station sites. The methodological approach uses GIS to seamlessly combine a variety of quantitative studies with qualitative stakeholder interviews. Subsequent quantitative studies, such as AHP-based decision modeling, network analysis, overlay analysis, and appropriateness modeling, are informed by qualitative inputs. Quantitatively speaking, the study optimizes BRT routes by means of a thorough appropriateness analysis, indicating a significant degree of variability in the 210.52 km² study region. AHP pairwise comparisons revealed that land use (0.0505) and population density (0.0832) were the two most significant characteristics. Suitability rankings vary from 105.91 to 291.91. Based on these findings, the study suggests seven BRT lines that range in length from 11.151 km to 27.158 km. Notably, Line 1, which is 17.813 kilometers long and intended for 10,000–15,000 users per day, has 31 stops and a max frequency of 10 minutes. The study's quantitative methodology is also used to determine operational needs, such as the number of buses (which can range from two to twenty-four) and the approximate round-trip time (1.425 hours). The suggested BRT lines are strategically aligned with locations that are highly suited, guaranteeing thorough coverage in residential zones and city centers. The study emphasizes the value of carefully developing the infrastructure of bus stops, with a focus on scalability and capacity matching with anticipated demand. Dynamic modeling provides a prospective perspective for ridership projections by accounting for shifting land use and population growth. A dynamic and adaptive approach is called for by the study, which acknowledges the inherent fluidity of urban surroundings.

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DESIGN REQUIREMENTS FOR THE FIREFIGHTING WATER AMOUNT NEEDED IN INDUSTRIAL BUILDINGS AND THEIR RELATIONSHIP TO GEOGRAPHIC INFORMATION SYSTEMS: A REVIEW PAPER

Journal European Journal of Interdisciplinary Research and Development

publisher PKP

Issue 2024

Volume 26

Industrial fires are the most costly compared to other fires. Water is the most common fire extinguishing agent because it has a set of physical and chemical properties that make it a very effective means of extinguishing, as it is applied either manually or automatically. The theoretical amounts of water needed for actual extinguishing are very low when calculated and provided in an effective manner. Therefore, it was necessary to propose several numerical models to estimate the amount of water that must be available in these buildings to extinguish fires if they occur or until support arrives from fire departments to complete the extinguishing process with the least possible loss of life and property that occurs in burning industrial buildings and nearby buildings that are exposed to fire. This research seeks to determine the relationship between firefighting water requirements and building design by reviewing current methods found in the literature for calculating firefighting water requirements and flow rates and discussing the extent to which they can be applied in the context of fire service procedures in industrial buildings. These flow rates can then be compared to the total capacity available at these buildings to determine if the available resources are sufficient. Some of these methods are designed to be interactive, so that the user can immediately see the effects of different parameters on the desired water flow rate. The ISO method and the Fire Risk Management Program method of the National Research Center of Canada are the most detailed and effective methods in taking into account many different factors, specifically related to the structure of the building and its relationship to neighboring buildings. Given that many fire service tasks depend on location, the importance of utilizing Geographic Information Systems to support fire service institutions has emerged, and by storing spatial data and making effective use of it, dynamic fire maps can produced and utilized in analyzing industrial building fires and predicting the effective ways to suppress them.

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SYNERGIZING GEOGRAPHIC INFORMATION SYSTEMS (GIS) AND MULTICRITERIA DECISION MAKING ANALYSIS (MCDA) FOR PUBLIC TRANSIT NETWORK OPTIMIZATION: A REVIEW

Journal Scholar's Digest- Journal of Multidisciplinary Studies

publisher Scholarsdigest.org

Issue 12

Volume 2

This paper provides a detailed overview of the integration of Geographic Information Systems (GIS) and Analytical Hierarchy Process (AHP) approaches in the optimization of public bus transport networks. The review includes a comprehensive analysis of the literature as well as a discussion of the major findings, computing effectiveness, utility, and possible directions for future research. Because it smoothly blends multi-criteria decision-making and spatial analysis, the combination of GIS and AHP shows to be a useful tool in handling the complexities inherent in public transportation planning. The study investigates the use of GIS in integrating optimization models, expressing network data, performing geographical and temporal analysis, and assisting in decision-making. It looks at studies that have utilized GIS to optimize routes in an efficient manner, showcasing the many approaches and methods that have been used in the literature. The report also identifies the primary findings and constraints of GIS and AHP integration research. The benefits of using GIS-AHP models in decision support systems for companies involved in urban planning and transportation are highlighted in the discussion. The study concludes with a prospective exploration of possible directions for future research, including the addition of new data sources, flexible demand modeling, and state-of-the-art optimization techniques.

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Analysis of Reinforced Concrete Beam Elements Impregnated with Ultra-High-Performance Fibers

Journal Texas Journal of Engineering and Technology

publisher zien journals

Issue 2023

Volume 22

The manner of seismic elements made of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) differs significantly from conventional concrete. However, limited research exists in the literature on the dynamic manner of UHPFRC seismic members due to their high cost. Limited element programs can reduce the need for experimental studies to develop design procedures for large-scale seismic elements. Validated analytical models can be utilised to investigate the impact of geometric changes, loading schemes, and reinforcement ratios on the seismic behaviour. This research employed a limited element program, specifically ABAQUS, to model a UHPFRC beam subjected to dynamic loading and evaluate the predictive accuracy of the numerical model. The material model parameters were determined based on uniaxial pressure and tensile tests. The findings from the numerical models demonstrate that the analytical model effectively predicts the dynamic behaviour of UHPFRC beams.

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Finite Element Analysis of Self-Compacted Concrete Filled Steel Tube Columns Exposed to High Temperatures

Journal International Journal of Analytical, Experimental and Finite Element Analysis

publisher rame.org

DOI https://doi.org/10.26706/ijaefea.1.10.20239252

Issue 1

Volume 10

To represent the structural behavior of self-compacted concrete filled steel tube composite columns under axial compression loading after high temperatures exposure, a nonlinear three-dimensional finite element analysis model has been achieved to analyze these columns using ANSYS R-15 software. An eight-node solid brick element (Solid65) is used to represent the concrete, while a four-node isoparametric shell element (Shell63) is used to represent the steel tube for the analyzed composite columns. A Newton-Raphson incremental-iterative approach is used to simulate the nonlinear solution technique. The finite element method results indicated that the predicted ultimate loads and axial deformations for the analyzed four column specimens agree well with the experimental results for normal strength and high strength concrete in static loading up to failure, and therefore, it is sufficient to model how these columns behave. The reduction in the analytical ultimate loads compared to the experimental values ranged from 11% and 16%, while the reduction in the total axial deformation values ranged from 3% to 7%. The yield patterns obtained from the analyzed composite columns under axial compressive stress are comparable to the yield patterns determined from the experimental study.

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Impact of Rapid Corrosion of Steel Bars on the Flexural Behavior of Reinforced Concrete Beams with Different Mix Proportions

Journal International Journal of Advances in Engineering and Emerging Technology (IJAEET)

Issue 1

Volume 14

The presented study is an experimental program to cast and test twelve small-scale reinforced concrete beams with three different mix proportions to determine the impact of rapid corrosion of bottom tension steel bars, using an electric corrosion cell, on the flexural behavior and ultimate capacity of the beams with variable corrosion degree. Using Faraday's Law and the amount of time spent to keep the samples inside the corrosion cell, the degree of corrosion (slight, moderate, and severe) is determined. The corrosion-related cracking pattern was the same for all beams and visually, did not indicate any loss in ultimate capabilities. Despite the significant degree of steel corrosion and the obvious spalling of the concrete cover, the highest corrosion-related fracture width was less than 1 mm. The ultimate flexural capacities and mid-span deflections decreased as an effect of the corrosion process in direct proportion to the degree of corrosion; the maximum loss in ultimate flexural capacity was for beam R2D which was 36%, and the maximum loss in mid-span deflection was for beam R1D which was 54%.

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Thermal conductivity and compressive strength of carbon fiber concrete

Journal Journal of Architectural Design

Issue 2022

Volume 13

This research includes an experimental study to find out the possibility of benefiting from the addition of Carbon Fiber Reinforced Polymers (CFRP) to the concrete mix in reducing the thermal conductivity of concrete and thereby reducing the heat transferred through the structures and elements of buildings, which leads to increased thermal insulation and reduce the electrical energy consumed to operate air conditioners. Eight rectangular concrete specimens are prepared and poured for thermal conductivity testing, in addition to 12 standard concrete cubes for compressive strength testing. CFRP strips cut in different proportions are added to find out the effect of the amount of these fibers on the thermal insulation of concrete and compare it with their effect on compression resistance. The results of the thermal conductivity tests for a test time of 390 minutes for each model showed that there is an increase in the insulation of concrete with added percentage of CFRP strips. The concrete specimens and cubes are classified into four groups according to the percentage of addition of CFRP, which was (0 %, 0.45 %, 1.1 %, and 1.6 %) by the weight of the cement allocated for the mixture. Despite the increase in insulation with the presence of fibers, there was a decrease in the compressive strength of concrete with an increase in the amount of fibers, where this decrease ranged between (6.4 - 28.5) % relative to the compressive strength of the reference concrete.

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DESIGN AND ANALYSIS OF FLAT AND GRID SLAB SYSTEM WITH CONVENTIONAL SLAB COMPARATIVE APPROACH

Journal International Journal of Advances in Engineering and Emerging Technology

Issue 2

Volume 30

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Green Concrete: Ferrock Applicability and Cost- Benefit Effective Analysis

Journal ASEAN Journal for Science and Engineering in Materials

publisher bumi publikasi nusantara

Issue 2

Volume 2

This research aims to assess the viability and suitability of Ferrock as an alternative to concrete for constructing foundations. The study evaluates the performance of Ferrock in foundation applications, compares its costs with traditional concrete, and examines the benefits of using Ferrock for foundations. To achieve these objectives, the utilization of Staad Pro and Foundation software is done to analyze the performance of Ferrock foundations. A cost-benefit analysis, considering factors like material costs, construction techniques, and maintenance requirements to determine the economic feasibility of Ferrock as a substitute for concrete and the potential to reduce carbon emissions, and promote environmentally friendly construction practices is also done. The research findings indicate that Ferrock exhibits promising performance characteristics for building foundations. It demonstrates comparable strength to traditional concrete while offering potential environmental benefits. Although implementing Ferrock may require an initial investment, the long-term advantages of reduced maintenance costs and improved sustainability contribute to its overall value proposition.

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Behavior of RPC Reinforced Wall Panels under Compression Action

Journal Solid State Technology

Issue 6

Volume 63

In the present work, experimental and numerical programs were conducted to investigate the compression action behavior of reinforced Reactive Powder Concrete (RPC) wall panels. Twelve different panels were tested and analyzed using the ANSYS software. All the panels were identical in dimensions, silica fume content, cement/sand ratio, and water/cement ratio. They were cast using five different concrete mixes, except the non-RPC mix. An experimental parametric study was followed to show the effect of volumetric steel fibers ratio, reinforcement ratio, hole size, hole location and hole shape on the general structural behavior, the mid-point deflection and the ultimate load capacity of the wall panels. A maximum enhancement by 86.2% in experimental ultimate load capacity was noticed for the panel having 2.0% steel fibers compared to the control panel. Also, the ultimate load capacity of the panels showed an almost linearly decreasing relationship with the size of the square hole centered at the center of the panel, while shifting the same original hole from the panel’s center nearer to the edge produced a negligible effect on the panel’s ultimate load capacity. Another important conclusion was that choosing a hole of square shape may be more critical, compared to a circular one, in such a wall panel. Finally, the use of ANSYS with a certain choice of the elements representing the concrete and the reinforcements gave consistently good agreement with the experimental values in terms of the mid-point deflection and the ultimate load capacity which corroborated the possible use of ANSYS, confidently, for further analyses of those panels with little need to further actual testing.

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Comparative Analysis of Lead Rubber Bearing and Friction Pendulum Bearing

Journal Solid State Technology

Issue 2s

Volume 63

Base isolation approach has become a critical segment to improve unwavering quality during a seismic earthquake. In now day by day's base detachment has become a relentlessly applied essential arrangement technique for structures and frameworks in significantly seismic zones in all viewpoint. The generally used separation system is Lead Rubber Bearing, Laminated Rubber Bearing and Friction Pendulum, channel Method, Pile Method and Damper part. Base separation is one of the most present day strategy and broadly acknowledged seismic insurance framework utilized in the structure in Earthquake inclined territories. The base detachment framework isolates the structures from its establishment and essentially moves it comparative with that of the super structure. The objective of this project is to comprehend the seismic exhibition of a G+10 unpredictable structure made of three distinct materials, for example, RCC, Steel and Composite with Lead Rubber Bearing (LRB) and Friction Pendulum Bearing (FPB) base isolation framework and to contrast the seismic reaction and without base isolation utilizing Response spectrum method in ETABS-2015 software. The reaction of the structure, for example, time period, base shear, story drifts and story displacements are studied and comparison is made. From this study it can also be concluded that it is better to provide isolation systems in seismic prone areas rather than providing fixed base and among two isolators used here FPB performs better than LRB for all the structures.

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Design of Reinforced Concrete Deep Beams using Particle Swarm Optimization Technique

Journal Karbala International Journal of Modern Science

publisher University of Karbala

DOI https://doi.org/10.33640/2405-609X.1180

Issue 4

Volume 5

Researches available in literature interrelating neural networks to civil engineering design problems, especially for beep beams, are very rare. Therefore, an optimization algorithm is developed and verified in this study and coded using MATLAB functions to determine the optimum cost design of reinforced concrete deep beams. ACI 318-14 code method is used benefiting from iterative particle swarm optimization technique due to its efficiency and reliability. Minimizing total cost is used as the objective function in terms of four decision variables. Self-adaptive penalty function technique is used to handle constraints for each of the 300 randomly selected particles, and in each of the 50 total iterations followed for each one of four suggested deep beam design case studies. Performing all iterations is used as a stopping criteria for the developed algorithm. Comparative studies are made to show the effect of concrete compressive strength, live load scheme, and length of deep beam, on the optimum total cost and the corresponding decision variables. Results presented in the form of graphs and tables show that the loading condition has a significant effect on the total cost of deep beams. The cost increase is accompanied by deep beam length increase, height increase, longitudinal reinforcement area increase and vertical shear reinforcement area decrease. The calculated optimum cost is noticed for beam DB1, which is 1255 US$, with 1.29 m beam height, 0.01445 m2 vertical shear reinforcement, 0.00914 m2 horizontal shear reinforcement and 0.00238 m2 main longitudinal reinforcement. The results show a relatively less difference in total cost between all the four beams at 4 m length compared to 8 m length. Also, a relatively mild increase in total cost is happened for beams DB3 and DB4 as the height increases, especially above 1.7 m height. As the main longitudinal reinforcement increases, cost of DB4 is affected more significantly than others, and as the vertical shear reinforcement increases, DB4 curve shows a relatively low degradation in cost.

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FLEXURAL BEHAVIOR OF HIGH STRENGTH REINFORCED CONCRETE BEAMS STRENGTHENED BY HYBRID FIBERS

Journal International Journal of Civil Engineering and Technology (IJCIET)

publisher iaeme

Issue 1

Volume 10

An experimental program is achieved to study the enhancement gained from adding different volumetric ratios of hybrid steel, basalt, and glass fibers to high strength concrete mixes, and to investigate the flexural behavior of rectangular reinforced concrete beams produced from these fibrous mixes. Ten rectangular beams, which are identical in geometry and reinforcement, are tested. The first one is a control beam, group A consist of three beams strengthened by different ratios of steel fibers only, group B consist of three beams strengthened by different ratios of hybrid steel-basalt fibers, and group C consist of three beams strengthened by different ratios of hybrid steel-glass fibers. Results and comparative studies expressed in the form of graphs and tables show variable enhancement values in crack, yield, and ultimate loads capacities for the tested beams. Standard high strength concrete cubes and cylinders test results indicate that compressive strength for all the fibrous mixes is slightly worsened, especially for hybrid steel-basalt fibers, due to the increase in matrix porosity whereas the splitting tensile strength is enhanced. Generally, yield and ultimate load capacities for most of the fibrous beams are reduced, especially for hybrid steel-basalt fibrous beams due to the smooth texture of basalt fibers. In addition, adding glass fibers hybridly with steel fibers enhances crack formation and propagation without a noticeable reduction in yield and ultimate load capacities.

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Improving Multiobjective Particle Swarm Optimization Method

Journal New Trends in Information and Communications Technology Applications

publisher Springer, Cham

DOI https://doi.org/10.1007/978-3-030-01653-1_9

Issue -

Volume -

An improved multiobjective particle swarm optimization algorithm is developed to get and compare Pareto fronts for constrained and unconstrained optimization test problems, with two objective functions and with a variable number of deci-sion variables, available in literature. A new Minimum Angular Distance Infor-mation technique, to assign the best local guide for each particle within the swarm to get the Pareto front in the polar coordinate system, is adopted and verified. An external repository (archive) is used to store the nondominated particles at the end of each iteration, and a crowding distance technique is followed to maintain the archive size and the front diversity for each test problem. A self-adaptive penalty function technique is used to handle the constraint functions through transform-ing the original objective functions into new penalized functions based on their amount of constraint violation at each iteration. The developed algorithm is coded by Matlab formulas and verified via thirteen well-known test problems. Test re-sults, represented in the regular Pareto fronts and the values of three comparative metrics (GD, S, and ER) calculated to verify the proposed algorithm, show more efficient and realistic agreements compared with that gained from previous stud-ies and algorithms. Applying different engineering design problems to the devel-oped algorithm is suggested as a future work.

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NSM Rebar and CFRP laminate strengthening for RC columns subjected to cyclic loading

Journal Construction and Building Materials

publisher Elsevier

DOI https://doi.org/10.1016/j.conbuildmat.2016.04.120

Issue 2016

Volume 119

An experimental program is achieved in this study conducted of three reinforced concrete column-stub specimens tested under increased cyclic lateral load to show the enhancement gained from using two well-known external strengthening techniques, which are NSM rebar and CFRP laminate, applied to partially cracked columns. Test data indicates that both of these strengthening techniques are efficient to enhance the overall behavior of the retrofitted columns like crack pattern, yield and ultimate cyclic load capacities, ductility ratio, dissipated energy capacity, initial stiffness degradation, and fracture mode. Strengthening Using CFRP laminates showed better enhancement in crack formation and propagation, while using MSN rebar showed better enhancement in load capacities, ductility ratio, and dissipated energy. Therefore, using NSM rebar may be a better choice for retrofitting and strengthening such cracked reinforced concrete columns that may be subjected to seismic event conditions.

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دراسة مختبرية لحساب الموصلية الحرارية لمونة ذات أنواع مختلفة من السمنت المتوفر في الأسواق المحلية

Journal Iraqi Journal of Civil Engineering

publisher هيئة التعليم التقني/ العراق

DOI https://doi.org/10.37650/ijce.2013.80535

Issue 1

Volume 9

تم في هذه الدراسة عمل اختبارات الموصلية الحرارية على واحد وعشرين نموذج لسبعة أنواع من مونة الخرسانة الاعتيادية المحتوية على أنواع مختلفة من السمنت الموجود في الأسواق المحلية لمدينة كركوك وبنفس الظروف القياسية. وقد تم حساب كمية انتقال الحرارة ضمن النماذج بالاعتماد على قانون فورير للتوصيل الحراري. وعند مقارنة النتائج العملية مع القيم النظرية المعتمدة في المصادر لحساب الأحمال الحرارية خلال الجدران الخرسانية تبين بأن نتائج الموصلية الحرارية لجميع النماذج أعطت توافقاً جيداً مع القيم النظرية. حيث أعطت نتائج فحص النموذج السابع والخاص بسمنت معمل السليمانية أقل قيمة موصلية حرارية والتي كانت (W/m.oC 1.162)، وأعلى قيمة موصلية حرارية كانت للنموذج الرابع الخاص بسمنت معمل شارغ/إيران وكانت (W/m.oC 1.55) والنموذج الثالث الخاص بسمنت معمل بازيان والتي كانت (W/m.oC 1.52). أما نتائج الموصلية الحرارية لباقي النماذج فقد كانت ضمن المدى المعتمد نظرياً. كما كان أقل مقدار انتقال حرارة ضمن المادة هو للنموذج السابع الخاص بسمنت معمل السليمانية، بينما أعلى مقدار لانتقال الحرارة كان للنموذج الرابع الخاص بسمنت معمل شارغ/إيران.

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تأثير التآكل المعجل لحديد تسليح الشد على تصرف الانحناء للعتبات الخرسانية المسلحة

Journal مجلة التقني للبحوث الهندسية

publisher هيئة التعليم التقني/ العراق

Issue 5

Volume 26

تتضمن هذه الدراسة برنامجا عمليا لصب وفحص اثنتا عشرة عتبة خرسانية مسلحة، وزعت على ثلاث نسب خلط وزنية، لمعرفة تأثير التآكل المعجل لحديد تسليح الشد السفلي باستخدام خلية تآكل كهربائية على تصرف الانحناء لهذه العتبات وسعتها القصوى وعلاقته مع اختلاف درجات التآكل ونسب خلط الخرسانة. حيث تم تقدير درجة التآكل (بسيطة، متوسطة، وشديدة) بالاعتماد على كمية الوزن النظري المفقود من مقطع حديد التسليح باستخدام قانون فراداي من خلال فترة بقاء النماذج داخل خلية التآكل. كان نمط ال ً تصدع نتيجة التآكل ثابتا لجميع العتبات المتآكلة ولم ً يعط تصورا عن مدى النقصان الحاصل في السعة القصوى واختلافه من عتبة إلى أخرى، حيث بدأت الشقوق في ً الاتجاه العمودي لحديد التسليح الطولي في منتصف فضاء العتبة تقريبا وبمعدل فقدان مقطع حديد التسليح مقداره .%٣.١ بالرغم من التآكل الشديد لحديد التسليح والتصدع الواضح لخرسانة الغطاء إلا أن عرض أكبر شق خرساني ناتج عن التآكل لم يتجاوز mm .1 سببت عملية التآك ً ل نقصانا في سعة التحمل الأقصى وتشوه المنتصف للعتبات تناسب مع درجة التآكل، حيث كان أكبر نقصان لحمل الانحناء الأقصى مقداره %٣٦ للعتبة D2R، وأكبر نقصان للتشوه مقداره %٥٤ للعتبة D1R. كما أعطت قراءات انفعال ا ً ً لخرسانة مع عمق العتبة تأثيرا واضحا للتآكل في زيادة هذه الانفعالات والتشققات وخاصة في منطقة الشد .

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تأثير كمية التقوية بشرائح ألياف الكربون على الموصلية الحرارية ومقاومة الإنضغاط للخرسانة

Journal مجلة التقني للبحوث الهندسية

publisher هيئة التعليم التقني/ العراق

Issue 6

Volume 24

يتضمن هذا البحث دراسة مختبرية لمعرفة إمكانية الاستفادة من التقوية بإضافة شرائح ألياف الكربون ((CFRP إلى الخلطة الخرسانية في تقليل الموصلية الحرارية الإجمالية للخرسانة المقواة وبالتالي تقليل الحرارة المنتقلة خلال تراكيب وعناصر الأبنية، مما يؤدي إلى زيادة العزل الحراري وتقليل الطاقة الكهربائية المستهلكة لتشغيل أجهزة التكييف. تم تحضير وصب (8) نماذج خرسانية مستطيلة المقطع لإجراء إختبار الموصلية الحرارية بالإضافة الى صب (12) مكعب خرساني قياسي لفحص مقاومة الانضغاط. تم إضافة شرائح ألياف الكربون المقطعة بنسب مختلفة لمعرفة تأثير كمية هذه الألياف على العزل الحراري للخرسانة ومقارنتها مع تأثيرها على مقاومة الانضغاط. وقد أظهرت نتائج إختبارات الموصلية الحرارية لوقت اختبار مقداره (390) دقيقة لكل نموذج أن هنالك زيادة في عازلية الخرسانة المضاف إليها شرائح ألياف الكربون وتزداد بزيادة كمية الألياف المضافة. وقد تم تصنيف النماذج والمكعبات الخرسانية إلى أربع مجموعات حسب نسبة الإضافة من ألياف الكربون والتي تراوحت ما بين (0 %، 0.45 %، 1.1 %، 1.6 %) من وزن السمنت المخصص للخلطة. وقد تم الحصول على أفضل عزل حراري بنسبة إضافة مقدارها (1.6) % ليصل فرق درجة الحرارة للسطحين الساخن والبارد إلى (5.5) oم في (285) دقيقة الذي يمثل وقت إطفاء السخان. وبالرغم من زيادة العازلية بوجود الألياف فقد كان هنالك نقصان في مقاومة إنضغاط الخرسانة مع زيادة كمية الألياف حيث تراوح هذا النقصان ما بين (6.4-28.5) % نسبة إلى مقاومة إنضغاط الخرسانة المرجعية.

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EXPERIMENTAL BEHAVIOR OF R.C. BEAMS PARTIALLY MAGED IN FLEXURE AND STRENGTHENED WITH CFRP LAMINATES

Journal مجلة التقني للبحوث الهندسية

publisher هيئة التعليم التقني/ العراق

Issue 1

Volume 23

This study presents an experimental investigation on the monotonic flexural behavior and ultimate capacity of reinforced concrete beams partially damaged and cracked in flexure due to applying a 58% of the predicted ultimate flexural load capacity, and then repaired by external strengthening with high strength CFRP (Carbon Fiber Reinforced Polymer) laminates bonded with epoxy resin to the tension face of concrete after doing all the appropriate preparations for the concrete adhesion substrate. Five rectangular reinforced concrete beams were tested to obtain the effect of amount of CFRP laminate on beams cracking behavior, concrete strains, ductility ratios, ultimate loads and failure modes. The results obtained from the adopted repairing and strengthening technique showed a significant effect of external high strength CFRP laminates on improving behavior and capacity of reinforced concrete beams. An increase by 15%- 33% in ultimate load capacities, for the CFRP strengthened beams, was observed over the control beam with conventional reinforcement. This gain in strength was accompanied by a reduction in ductility ratio by 18%- 28% for the CFRP strengthened beams compared with the control R.C. beam. Also, the crack patterns show enhanced performance in crack distribution and propagation for the strengthened beams over the control beam.

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