In this study, nonlinear 2-D finite element approach was utilized to study the behavior of the rigid connection between steel girder and RC Column using stiffener and stud shear connectors. Two types of connections were analyzed. The position of stud shear connectors is the only difference between the two types. The behavior of the connection is focused and represented by the behavior of the stiffener, stud shear connectors, flange, bond stress and load transfer mechanism. In designing the specimens, studs were considered as main parameter. Load transfer mechanism of the specimens was considered in detail to provide some good information for understanding the behavior of the connection. It was found that in specimen with stud shear connectors, the stiffener carries tension forces larger than that in case of specimens without stud shear connectors and vice versa for compression force. The rigidities of the two analyzed types of specimens are still maintained even after yielding of reinforcement. It was found that the connection possesses a suitable degree of rigidity and it is very convenient for bridges especially in seismic regions. Anchorage length of reinforcement must be provided such that the average bond stress does not exceed the allowable limits. The role of studs in the stiffener is to distribute the stress from stiffeners to concrete in compression side and to transfer the stress from concrete to the stiffener in tension side. If no studs exist in the stiffeners, it was found that stress concentration occurs in the transferring the stress concentration at the topside of the stiffener which may occur if no studs exist.

In this research, the beam-column joint having lateral beams and slab was considered. The specimens receive two direction loadings. For reporting the influence of two directional loadings, lateral beams and slab in analysis, Three-dimensional nonlinear FEM analysis was done. The examination was done for obtaining fundamental data regarding the influence of the lateral beams, slab and two direction Loadings (forty five degree directional loadings). In addition, the purpose of this examination is to research the earthquake-proof efficiency of the joint. The most of seismic design provisions for RC joints of high rise buildings in all Seismic Guidelines around the world are based on earlier experimental studies. Design Guidelines for Earthquake Resistant RC Buildings Based on Ultimate Strength Concept, suggests that a 3-D interior beamcolumn joint should be independently designed for two principal directions. However, it is necessary to establish a more rational performance evaluation design for joints under two directional seismic forces. This can be accomplished by analytical study of stress transfer mechanisms of joints. Beam-column joints in reinforced concrete buildings are generally subjected to forces in two orthogonal directions during an earthquake. The structural performance of the joints under such seismic forces has not been understood clearly and rationally in previous studies. The stress transfer mechanisms of these joints are a 3-D problem, and the joint is confined by its lateral reinforcement, transverse beams, a slab and column axial forces. It is necessary to understand the structural performance of joints subjected to two directional seismic forces, not only by experimental studies but also by using 3-D analytical techniques. In order to understand the damages of concrete in a joint, moreover, accumulated consumption energy of concrete elements in FEM analysis was calculated. It is very important to discuss the stress transfer mechanisms and the damages of concrete in a joint toward the establishing of a more rational performance evaluation design of RC structures.

Nonlinear 3D FE is utilized to investigate the nonlinear behavior of RC internal and external joints of frames during cyclic loading. The factors affecting the behavior of RC joints include; dimensions and details of joints, main reinforcement ratios and shear reinforcement ratios of beams and columns and presence of slab. The items of the behavior such as; the hysteresis loops and the envelope curves of joints, shear strength, flexural shear strength, ductility level, and comparison between behavior of external and internal joints. The study showed the necessity of applying the weak beam – strong column concept on design of such joints. The plastic hinges should occur in the beams not on the columns to avoid brittle failure during earthquake. Presence of slab caused an increase and improvement of both strength and ductility.

تمثل المئذنة إحدى العناصر المعمارية المهمة التي اقترنت بعمارة المساجد، وقد جاءت هذه الأهمية نتيجة للدور الوظيفي للمئذنة بالإضافة لدورها التشكيلي والرمزي، حيث إن لها خصائص معمارية متميزة فأصبحت بارتفاعها علامة أرضية (Land Mark) داخل المدن الإسلامية. وقد تأثر شكل وتصميم المآذن عبر العصور الإسلامية المختلفة بالمعطيات الخاصة بكل منطقة جغرافية والعوامل السياسية ونظم الحكم. ونتيجة لما ظهر من فترات حكم مشتركة بين اليمن ومصر فقد ظهرت فكرة الورقة البحثية لدراسة تحليلية لتأثير الأنماط السائدة في عمارة العصور الإسلامية المختلفة على عمارة المآذن في البلدين ثم مقارنة النتاج المعماري بين أهم المآذن في العصور الإسلامية المختلفة التي ظهرت في البلدين منذ عصر صدر الإسلام وحتى العصر العثماني، وتم تحديد منطقة الدراسة باليمن في إقليم المرتفعات الغربية والوسطى في اليمن والتي تضم مناطق (صنعاء وذمار وشبام كوكبان وإب وتعز) وبمصر فى مآذن القاهرة ولتحقيق هدف الورقة البحثية تمعرض المفاهيم الخاصة بالمئذنة ونشأتها وتطورها في العالم الإسلامي في الجزء الأول من الورقة البحثية، بينما في الجزء الثاني من الورقة البحثية تم دراسة عمارة المآذن في كل من اليمن ومصر في الفترة الزمنية المحددة، ومن ثم تم عمل تحليل مقارن لتطور عمارة المآذن في اليمن ومصر واستخلاص أهم جوانب التوافق والاختلاف فيما بينها ومدى تأثير الأنماط السائدة في العالم الإسلامي على عمارة المآذن في البلدين. ويخلص البحث إلى أن عمارة المآذن في اليمن ومصر تأثرت بالأنماط السائدة في العالم الإسلامي، وإن كان ذلك التأثير محدود في مآذن اليمن حيث طغى تأثير الطابع المحلي للمنطقة، حيث تعددت الدويلات التي حكمت اليمن والتي أفرزت أنماط متباينة في نفس المرحلة، كما ظهر التأثير المتبادل في عمارة المآذن في البلدين في بعض المراحل.

تمثل المئذنة إحدى العناصر المعمارية المهمة التي اقترنت بعمارة المساجد، وقد جاءت هذه الأهمية نتيجة للدور الوظيفي للمئذنة بالإضافة لدورها التشكيلي والرمزي، حيث إن لها خصائص معمارية متميزة فأصبحت بارتفاعها علامة أرضية (Land Mark) داخل المدن الإسلامية. وقد تأثر شكل وتصميم المآذن عبر العصور الإسلامية المختلفة بالمعطيات الخاصة بكل منطقة جغرافية والعوامل السياسية ونظم الحكم. ونتيجة لما ظهر من فترات حكم مشتركة بين اليمن ومصر فقد ظهرت فكرة الورقة البحثية لدراسة تحليلية لتأثير الأنماط السائدة في عمارة العصور الإسلامية المختلفة على عمارة المآذن في البلدين ثم مقارنة النتاج المعماري بين أهم المآذن في العصور الإسلامية المختلفة التي ظهرت في البلدين منذ عصر صدر الإسلام وحتى العصر العثماني، وتم تحديد منطقة الدراسة باليمن في إقليم المرتفعات الغربية والوسطى في اليمن والتي تضم مناطق (صنعاء وذمار وشبام كوكبان وإب وتعز) وبمصر فى مآذن القاهرة ولتحقيق هدف الورقة البحثية تمعرض المفاهيم الخاصة بالمئذنة ونشأتها وتطورها في العالم الإسلامي في الجزء الأول من الورقة البحثية، بينما في الجزء الثاني من الورقة البحثية تم دراسة عمارة المآذن في كل من اليمن ومصر في الفترة الزمنية المحددة، ومن ثم تم عمل تحليل مقارن لتطور عمارة المآذن في اليمن ومصر واستخلاص أهم جوانب التوافق والاختلاف فيما بينها ومدى تأثير الأنماط السائدة في العالم الإسلامي على عمارة المآذن في البلدين. ويخلص البحث إلى أن عمارة المآذن في اليمن ومصر تأثرت بالأنماط السائدة في العالم الإسلامي، وإن كان ذلك التأثير محدود في مآذن اليمن حيث طغى تأثير الطابع المحلي للمنطقة، حيث تعددت الدويلات التي حكمت اليمن والتي أفرزت أنماط متباينة في نفس المرحلة، كما ظهر التأثير المتبادل في عمارة المآذن في البلدين في بعض المراحل.

ABSTRACT Stope stability is a key factor for the success of a mining operation. To optimise ore productivity while maintaining stope stability, the mining block/stope must be extracted in stages. Ore dilution will occur if the stope is not properly excavated/blasted. This study examines stope stability during mining in three stages, where the height of each stage stope is 10 m. The paper also presents simulation analysis of a typical steeply dipping tabular orebody at 1200 m depth below the surface, which is common in many Canadian underground hard rock mines. Numerical modelling analysis was conducted using the finite element program, RS2D, where the non-linear elasto-plastic Mohr-Coulomb failure criterion was adopted. The rock reinforcement system (i.e. cable bolts) was modelled/installed in the stope footwall after each mining stage to strengthen access drifts and stabilise the rock mass around the stope that was disturbed by mining activity. Results are discussed in terms of depth of failure zones, total deformation and axial forces in cable bolts with respect to mining stage.

ABSTRACT Purpose. The objective of this study is to determine the best operating conditions for the most notable drilling parameters (i.e. weight on bit (WOB), rotary drilling speed (RPM), and characteristics of drilling fluid) using field data obtained from El-Sharara Oil Field. Methods. The used data has been extracted from daily drilling reports of well named (NC-186/K04h) field. Such data contains information about the geological formations, casing strings, drill-bits, fuel consumption, flow rate of drilling fluid and other drilling parameters. Findings. The results reveal that, the lower geological formations of El-Sharara Oil Field, the harder are the upper formations. Therefore, it is recommended to apply heavy loads (i.e. WOB of 45000 lb) with low drilling speed (i.e. 100 rpm) in the lower formations; and to apply small loads (i.e. WOB of 19000 lb) with high drilling speed (i.e. 160 rpm) in the upper formations. Originality. This study evaluates the performance of drilling operation based on the interaction between rock formations and machine drilling parameters. Practical implications. Understanding such interaction between rock formations and machine drilling parameters will remarkably improve the rate of penetration (ROP) in the related geological formations. Consequently, the overall drilling costs will be reduced in terms of drilling time, life of drill-bit and fuel consumption.

ABSTRACT Purpose. The objective of this study is to determine the best operating conditions for the most notable drilling parameters (i.e. weight on bit (WOB), rotary drilling speed (RPM), and characteristics of drilling fluid) using field data obtained from El-Sharara Oil Field. Methods. The used data has been extracted from daily drilling reports of well named (NC-186/K04h) field. Such data contains information about the geological formations, casing strings, drill-bits, fuel consumption, flow rate of drilling fluid and other drilling parameters. Findings. The results reveal that, the lower geological formations of El-Sharara Oil Field, the harder are the upper formations. Therefore, it is recommended to apply heavy loads (i.e. WOB of 45000 lb) with low drilling speed (i.e. 100 rpm) in the lower formations; and to apply small loads (i.e. WOB of 19000 lb) with high drilling speed (i.e. 160 rpm) in the upper formations. Originality. This study evaluates the performance of drilling operation based on the interaction between rock formations and machine drilling parameters. Practical implications. Understanding such interaction between rock formations and machine drilling parameters will remarkably improve the rate of penetration (ROP) in the related geological formations. Consequently, the overall drilling costs will be reduced in terms of drilling time, life of drill-bit and fuel consumption.

ABSTRACT Purpose. The objective of this study is to determine the best operating conditions for the most notable drilling parameters (i.e. weight on bit (WOB), rotary drilling speed (RPM), and characteristics of drilling fluid) using field data obtained from El-Sharara Oil Field. Methods. The used data has been extracted from daily drilling reports of well named (NC-186/K04h) field. Such data contains information about the geological formations, casing strings, drill-bits, fuel consumption, flow rate of drilling fluid and other drilling parameters. Findings. The results reveal that, the lower geological formations of El-Sharara Oil Field, the harder are the upper formations. Therefore, it is recommended to apply heavy loads (i.e. WOB of 45000 lb) with low drilling speed (i.e. 100 rpm) in the lower formations; and to apply small loads (i.e. WOB of 19000 lb) with high drilling speed (i.e. 160 rpm) in the upper formations. Originality. This study evaluates the performance of drilling operation based on the interaction between rock formations and machine drilling parameters. Practical implications. Understanding such interaction between rock formations and machine drilling parameters will remarkably improve the rate of penetration (ROP) in the related geological formations. Consequently, the overall drilling costs will be reduced in terms of drilling time, life of drill-bit and fuel consumption.

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