Current Status and Challenges of Using Internet by Libyan Higher Education

تهدف هذه الورقة الى تسليط الضوء على واقع توظيف الإنترنت في العملية التعليمية في ليبيا ودراسة المعوقات التي تقف امام تعزيز اسلوب التعليم الإلكتروني في مؤسسات التعليم العالي. كما تبين الورقة اهم الإشكاليات التي تواجه التعليم العالي في ليبيا وتعرض مستوى جودة التعليم في ليبيا مقارنة بالمحيط الإقليمي والدولي طبقا لدراسات وابحاث سابقة. تم الاعتماد على المنهج الوصفي وأسلوب المسح بالعينة لتحقيق أهداف الدراسة.  تشير الدراسات والتقارير المحلية والدولية السابقة الى مؤسسات التعليم العالي الليبية تعاني من مشاكل مزمنة ولها تصنيف متأخر جدا إقليميا ودوليا كذلك فإن حجم المشاركة للجامعات الليبية على شبكة المعلومات الدولية هو متدني جدا أيضا. وبالاستناد لنتائج المسح فإن معظم أعضاء هيئة التدريس مقتنعون بتوظيف الإنترنت في العملية التعليمية وعلى الرغم من ذلك فإن جزء كبير منهم لا يستخدمها في العملية التعليمية حيث يعتبر حجم استغلال شبكة الإنترنت لعينة الدراسة ضعيف جدا.The main objective of this research paper is to highlight the current status of the internet usability within Libyan higher education institutions, as long with studying the difficulties that mitigate electronic education in Libya. Also, this paper raises up the critical problems that facing higher education in the country. Aiming to conduct a firm study, previous studies have been reviewed to make quality comparison between Libyan higher education system and other regional and international education systems. In order to achieve the objectives of the paper the descriptive approach and the survey method have been used. Previous Libyan and international studies and reports indicate that Libyan higher education lists among the lower qualitied education system in the world. Based on surveys, most faculty members in Libyan universities believe of importance of internet in the education process. In contrast, a lot of the faculty members do not use the internet for the purpose of education

Finite element modeling of concrete-filled steel tubes : review and recent developments

The paper reviews previous investigations in the area of finite-element modeling of concrete-filled steel tubes. The literature provides a summary of the main type of the elements that are most frequently used to simulate concrete, steel and the interaction between the steel and the concrete in the composite beam and column members. A summary of confined concrete models is presented. Finally, finite-element were developed for 12 triangular concrete filled fabricated VHS-plate stub column specimens tested and reported in previous research [1, 2]. The confined concrete models, reviewed in the literature, were employed in the simulation and comparison was made to find the most suitable model for this type of column

Explicit Simulation of Circular CFST Stub Columns with External Steel Confinement under Axial Compression

Concrete-filled steel tube (CFST) structural members have been widely used in engineering projects for their superior strength and ductility. However, the different lateral dilation characteristics between concrete infill and steel tube have caused imperfect composite interaction during the early loading stage. To overcome this issue, external steel confinements in the form of rings and spiral were previously suggested to minimise the lateral expansion of the steel tube and enhance the concrete confinement effects. This study presented the analytical behaviour of circular CFST short columns with an external ring or spiral confinements which are subjected to axial loading. An explicit finite element (FE) model was developed and verified based on previous experimental findings. Besides that, this study analysed the failure modes, axial load–strain relationship, stress distributions, and bond strength of the composite column components. Parametric analysis was also undertaken to evaluate the impact of material strengths, total steel ratio, and diameter-to-thickness ratio. The results suggest that the use of external steel confinement can enhance the compressive behaviour of CFSTs better than increasing the thickness of the steel tube when using the same steel ratio. Finally, simplified design formulations were developed to accurately calculate the ultimate capacity of CFST columns with and without external steel confinement

Sustainable concrete : overview of recent developments and applications

The purpose of this paper is to present the latest developments of the area of sustainable concrete. The paper will highlight some of the technologies that suit the Libyan case, to help decision-makers in Libya to move towards efficient and sustainable structures. One of the recent trends to shift towards more green and sustainable concrete is by utilizing alternative aggregates. The recycling of construction materials such as concrete or non-construction materials such as glass and scrap tires, or even some by-product materials such as steel slag, then the use of these materials as alternative aggregates in sustainable concrete. The use of alternative raw materials from waste or by-products of different industries, and the replacement of conventional fuels with alternative fuels, are other trends to advance the sustainability of concrete and better the cement industry. Nevertheless, most of these technologies are still facing different obstacles to be adopted in all civil engineering projects

The behavior of concrete reinforced by higher proportion of date palm fibers

Over the recent decades, scientists have begun to search for more sustainable and environmentally friendly materials. It is well known that construction materials are among the most commonly used materials, and have a clear negative impact on the environment. Therefore, this paper aims to discuss the possibility of using waste from date palm trees in concrete as a natural alternative to the conventional fibers. Previous studies concentrated on examining the behavior of lower dosages or short length of male date palm surfaces fibers (MDPSF) in concrete. In this study, MDPSF concrete specimens made by using higher dosages and longer length of fiber were tested. The mechanical properties of the date palm tree fiber have been investigated. In addition, flexural and compressive behavior of concrete specimens reinforced with different ratios and length of palm tree fiber, were studied. The results show clear improvement in flexural strength when MDPSF was added. Furthermore, by adding MDPSF the ductility of beam specimens was increased. An increase in compressive strength was achieved by adding MDPSF

Effect of date palm fibers on the mechanical properties of concrete

Over the recent decades, scientists have begun to search for more sustainable and environmentally friendly materials. It is well known that construction materials are among the most commonly used materials, and have a clear negative impact on the environment. Therefore, this paper aims to discuss the possibility of using waste from date palm trees in concrete as a natural alternative to the conventional fibers. Previous studies concentrated on examining the behavior of lower dosages or short length of male date palm surfaces fibers (MDPSF) in concrete. In this study, MDPSF concrete specimens made by using higher dosages and longer length of fiber were tested. The mechanical properties of the date palm tree fiber have been investigated. In addition, flexural and compressive behavior of concrete specimens reinforced with different ratios and length of palm tree fiber, were studied. The results show clear improvement in flexural strength when MDPSF was added. Furthermore, by adding MDPSF the ductility of beam specimens was increased. An increase in compressive strength was achieved by adding MDPSF

Fabricated VHS tube to high-strength steel plate triangular concrete filled stub columns under axial compression load

This paper investigates the behaviour of six concrete filled fabricated very high strength (VHS) tube to high-strength steel plate triangular stub columns under axial compression load. The specimens are triangular in cross-section and consist of three high-strength steel plates connected to very-high strength steel tubes at the vertices. In this study high-strength plates of grade 450 were used. The VHS tubes are of 38mm diameter and 1.6mm thickness, have a nominal yield stress (fy) of 1350 MPa and nominal ultimate strength of (fu) 1500 MPa. Four international standards; the Australian Bridge Design Standard for Steel and Composite Construction (AS 5100.6-2004), the American Concrete Institute Standard (AC I318-2002), The British Standard of Steel, Concrete and Composite bridges (BS5400-2005) and the Chinese standard for concrete-filled steel tubular structures (DBJ 3-51: 2003), were used to predict the ultimate carrying capacities of the specimens and compared with the experimental results. New models are proposed based on mechanical properties of the heat-affected zone and plate buckling. Recommendations for future studies are made based on comparative studies

Stiffened concrete-filled steel tubes : a systematic review

The behavior of concrete filled steel tubular (CFST) elements with different types of stiffening measures has been wildly investigated during the past two decades through experimental, analytical, and numerical approaches. The previous studies highlighted the importance of the presence of internal and external stiffeners to enhance the structural performance of CFST elements under different loading conditions. In this paper, a systematic methodology is proposed in order to rigorously review the current knowledge in literature about stiffened CFSTs. The reviewed studies include tests of static axial compression, pure bending and combined of static loading actions as well as the cyclic behavior and the fire resistance. A coherent taxonomy regarding the research of stiffened CFSTs is proposed based on the loading conditions besides their cross-sectional shape and type of stiffeners. The study also presents a number of practical applications of stiffened CFSTs in different engineering projects. Finally, concluding remarks, current research gap and future research directions on stiffened CFST are provided and discussed

Concrete filled fabricated VHS tube to mild steel plate triangular stub columns under axial compression load

This paper investigates the section capacity of a series of concrete filled fabricated VHS tubeplate triangular sections under axial compression. The behavior of empty fabricated sections made up of mild steel plates with tubes at the corners was investigated in previous studies which have proven the effectiveness of the use of the empty fabricated VHS-plate section columns. In this paper concrete-filled fabricated triangular columns made up of VHS tubes at the vertices that are welded to mild steel plates are tested. Concrete-filling results in reduction in cross sections of the columns thereby reducing construction costs and contributing to sustainability. The VHS tubes used in this investigation have a nominal yield stress of 1350MPa, nominal ultimate strength of 1500MPa, 38.1mm outer diameter and 1.6 wall thicknesses. Steel plates of grade 250 with a 3mm wall thickness were used as facet plates. Experimental tests were conducted to determine the loaddeformation curves and understand the behavior of the concrete filled VHS fabricated triangular sections. In addition, the paper assesses four international specifications used to design concrete filled steel columns, and compares their prediction to experimental results.The specimens'carrying capacitieswere also determined using the Australian standards taking into account the effective section area