أحمد عاجل علي المجتومي

The three-dimensional finite element model was developed to analyze semi-rigid beam-to-column connections, considering factors like bolt pretension and the contact between various surfaces. Experimental data validates the model, revealing strong correlations in load displacement and moment rotation characteristics. A parametric study involving seventy-five models explores the influence of various geometric parameters, particularly beam size, on connection performance. The main results show that for the same beam size, increasing the thickness of the flange angle makes it stronger against moments but less able to rotate. On the other hand, larger flange gages make the initial stiffness lower and the final rotation higher. Additionally, thicker web angles improve ultimate moment capacity but also limit rotation.

The possibility of consuming artificial neural networks (ANN) using Matlab software to calculate the rotational capacity of steel cold-formed C- and Z-section purlins. Rotational capacity is a significant phenomenon as in the situation of steel purlins which are extensively used in roofing wide-ranging buildings. The complex conducts of such members make the conventional design approaches not satisfactory from a reliability standpoint. The main aim of this paper was to give a quick and precise technique for estimating local buckling capacity of C-and Z-section purlin. Good agreement was attained concerning (ANN) technics outcomes and data from literature. Trained neural network develops easy to-utilize method for calculating yielding and ultimate moment's capacity of C-and Z-section. Broad parametric investigations were additionally performed and introduced graphically to analyse the impact of geometric and mechanical properties on rotational capacity. It was found that the proposed (ANN) based technics is practical in predicting both the yield and buckling rotational strength of cold-formed purlin steel sections.

This research submits theoretical and experimental realization of shear behavior of RC I-beams with polypropylene fiber with different volume fraction of plastic fiber as additive. The enhance of the sustainability of structural elements through the development of its mechanical performance by adding new materials such as plastic raw materials has become more important in the current period , particularly I-beams that was used in the long spans structure to become more environmentally-friendly. Seven specimens were tested in this study and only the amount of fiber volume fraction was varied. Experimental results showed that the ultimate strengths are increased in range (4.4% to 35.27%) that of control IB-1 for the tested beams containing Polypropylene Fiber Reinforced Concrete (PPFRC) with varied amount percentage of fiber material. Crack arrest mechanism of polypropylene fibers, and compressive strength of concrete increased in range (7.42% to 29.3%) that of plain concrete, and improved the tensile response in range (8.36% to 92.7%) that of plain concrete, limited crack propagation. So, improved behavior was obtained. ANSYS 11, Finite Element models software are used to emulate two tested I-beams. 3D-nonlinear solid elements was utilized to model the concrete, while, the steel reinforcement was demonstrated by spar element. It was found that the general practices of the FE models demonstrated acceptable concurrence with perceptions and information from the experimental…

The ability to reasonably predict the response of steel structures under fire effects is of great importance in structural fire safety design. This paper presents neural networks prediction of axial load capacity for steel columns in fire. An algorithm of back propagation neural network with the log-sigmoid activation function is adopted because of its precision and results enhancement of foretelling. The legitimacy of the technique is tried by contrasting and distributed test information on steel columns at surrounding and elevated heat. The examinations demonstrate such technique gives great correlation with test result. Parametric studies have been done to evaluate the impacts of cross sectional shape, slenderness ratios and eccentricity of loading on the carrying capacity of steel columns under fire. The slim sections of steel columns with slenderness ratio domain (100-140) react distinctively by showing an abundantly decreased rate of loss in strength within the temperature domain (20°C - 300°C). This domain diminishes further with expanding slenderness ratios, and for middle columns with slenderness ratio domain (40-80), is like that of stumpy columns however at decreased buckling stress. Be that as it may, in this scope of (L/R) ratios the lessening in stress with expanding temperature is regular and demonstrates no sudden drop, because of the collaboration amongst buckling and yielding. On other hand, the eccentricity of loading on the carrying capacity of steel columns under fire shows that the slender column, (slenderness ratio) greater than 120, the column demonstrates a diminishing impact of used eccentricity of loadings with expanding slenderness ratios. This might be as a consequence of more impelled thermal bowing that is straightforwardly relative to the column length. And the load-eccentricity characteristics of the intermediate column, (slenderness ratio) domain (20 – 60), are schemed at increasing temperature gradient. It is fascinating to observe that the eccentricity of the limit of maximum column load capacity slightly effected with temperature gradient. It is trusted that the important data gave in this work will be helpful in giving a superior comprehension on the genuine behavior of steel sections in fire and a great step in improving the method of design.

This paper is devoted to investigate the behavior of fibrous concrete beams under combined bending and torsion using a non-linear three-dimensional finite element model. The 20-noded isoparametric brick elements have been used to model the concrete. The reinforcing bars are idealized as axial members embedded within the concrete element and perfect bond between the concrete and the reinforcement has been assumed to occur. Two types of fibrous concrete beams set under combined bending and torsion have been analyzed and the finite element solutions were compared with the experimental data. Several parametric studies have been carried out to investigate the effect of some important material parameters. In general, good agreement between the finite element solutions and the experimental results was obtained. The three-dimensional finite element model, which has been adopted in the present research, is suitable to predict the behavior of reinforced concrete beams subjected to combined bending and

نشر الدكتور احمد عاجل علي المجتومي أحد تدريسيي قسم الهندسة المنشآت والموارد المائية في كلية الهندسة بجامعة الكوفة بحثا علميا بعنوان: (THE ROTATIONAL CAPACITY OF COLD-FORMED PURLIN STEEL SECTIONS USING ARTIFICIAL NEURAL NETWORKS) في المجلة العالمية (International Journal of Civil Engineering and Technology)، (Volume 8, Issue 12, December 2017, pp. 362–372, Article ID: IJCIET_08_12_043). والتي تنشر ضمن: (IAEME publication Scopus indexed). وبين المجتومي : ان ظاهرة الالتواء للمقاطع الحديدية المشكلة على البارد من الظاهر المهمة المؤثرة بشكل كبير على الاعتاب الحديدية وبالخصوص المدادات والتي بدورها تستخدم على نطاق واسع في اعمال تسقيف المنشآت الحديدية , ان التصرف المعقد لهذه الاعضاء الانشائية جعل الطرق المقترحة التصميمة غير مجدية من النواحي الاقتصادية مما اثار العديد من المحاولات البحثية في هذا المجال . ان البحث كان الهدف الرئيسي من هذا البحث هو إعطاء تقنية سريعة ودقيقة لتقدير عزوم الالتواء المحلي للمقاطع الحديدية المشكلة على البارد ذات الشكل C) & (Z-section. تم التوصل إلى نتائج جيدة لقيم العزوم المستهدفة وكذلك كفاءة التمثيل الرياضي بواسطة الشبكات العصبية الصناعية (ANN) تم كذلك استخدام الموديل لعمل دراسات خاصة بتأثير المتغيرات للمقاطع على قيم عزوم الخضوع والعزم الاقصى للمقاطع وتم عرضها رسوميا . Available online at http://http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=8&IType=12