Different types of concrete mixtures are used as building materials. The manufacturing process of two-stage concrete (TSC) differs from that of conventional concrete. This study investigated conventional mechanical properties derive empirical relations for estimation of the mechanical parameters of TSC and conventional concrete mixtures. TSC was used to prepare 216 specimens and conventional concrete was used to prepare 108 specimens that then were aged for 28 days. Uniaxial compression, Brazilian tensile strength, and point load tests were carried out as destructive testing. Schmidt hammer and ultrasonic pulse velocity tests were carried out as nondestructive testing. The data from testing were categorized as regression or test data. Empirical relations were derived between the parameters for the two types of concrete, and these relations were validated. It was concluded that indirect, nondestructive testing of engineering materials, including concrete, considerably increases the speed and decreases the estimation cost of determining the mechanical parameters. This method can be recommended for estimation of these mechanical parameters. arabic 13 English 97
Hakim S. Abdelgader(7-2020)

Estimating the service life of Reinforced Concrete (RC) bridge structures located in corrosive marine environments of a great importance to their owners/engineers. Traditionally, bridge owners/engineers relied more on subjective engineering judgment, e.g. visual inspection, in their estimation approach. However, because financial resources are often limited, rational calculation methods of estimation are needed to aid in making reliable and more accurate predictions of the service life of RC structures. This is in order to direct funds to bridges found to be the most critical. Criticality of the structure can be considered either from the Structural Capacity (i.e. Ultimate Limit State) or from Serviceability viewpoint whichever is adopted. This paper considers the service life of the structure only from the Structural Capacity viewpoint. Considering the great variability associated with the parameters involved in the estimation process, the probabilistic approach is most suited. The probabilistic modelling adopted here used Monte Carlo simulation technique to estimate the Reliability (i.e. Probability of Failure) of the structure under consideration. In this paper the authors used their own experimental data for the Correlation Length (CL) for the most important deterioration parameters. The CL is a parameter of the Correlation Function (CF) by which the spatial fluctuation of a certain deterioration parameter is described. The CL data used here were produced by analyzing 45 chloride profiles obtained from a 30 years old RC bridge located in a marine environment. The service life of the structure was predicted in terms of the load carrying capacity of an RC bridge beam girder. The analysis showed that the influence of SV is only evident if the reliability of the structure is governed by the Flexure failure rather than by the Shear failure. arabic 14 English 80
Omran Mohamed Saleh Kenshel(2-2021)

تمثل الطرق العمود الفقري للبلاد والذي تتمحور حوله وحدة البلاد ونموها وتطورها ، ومما لاشك فيه بأن وجود شبكة متطورة من الطرق في الدولة يمكنها من تحقيق أهدافها وسياساتها المختلفة، فالتقدم في تخطيط وتنفيذ الطرق يعمل على تغيير نمط الحياة ورفع مستوى المعيشة ويساهم في تطور ونمو المجتمعات .تناولت هذه الدراسة البحث في موضوع عوامل ومعايير التصميم الهندسي للطرق ، وأستعرضت كلا من إعتبارات التصميم القديمة والعوامل المطورة لها ، والإعتبارات الأساسية الحديثة للتصميم، كما تطرقت إلى العناصر الأساسية والثانوية للتصميم الهندسي للطرق ، وقدمت لمحة عن مدى تأثير تصميم الطريق على سلامة المرور .وتم عمل مقارنة بين معايير التصميم الهندسي للطرق الحضرية مأخوذة من أربع أدلة تصميم مختلفة، والأدلة على التوالي هي :دليل التصميم الهندسي للطرق لولاية أريزونا الأمريكية ، ودليل التصميم الهندسي للطرق لجنوب أفريقيا ، ودليل التصميم الهندسي للطرق للسعودية، ومشروع إعداد دليل معايير التصاميم الهندسية لشبكة الطرق في ليبيا (الجزء الخاص بالطرق الحضرية) ، وأعطت تقييم عن المعايير المطبقة في ليبيا من خلال أمثلة لبعض مقاطع الطرق القائمة في مدينة طرابلس، كما ناقشت بعض المشاكل الناتجة عن عيوب معايير التصميم والتخطيط في المدينة ، وأهم ما قدم من مقترحات لمعالجتها .كما تم عمل دراسة تحليلية ( إستبيان ) كان الغرض منه التوصل إلى مجموعة من الأهداف وهي كالتالي:التعرف على نشاط الدولة الليبية في أعمال تصميم الطرق من عدمه .انطلاقا من أي مرجعية يتم تصميم الطرق في ليبيا ؟مدى اختلاف معايير التصميم باختلاف الفترات الزمنية التي تم فيها التصميم .مدى مواكبة معايير التصميم المستخدمة حالياً في ليبيا للتطور العمراني .مدى تأثير معايير التصميم على السلامة العامة لكل من الركاب والمشاة والبيئة .وختاما وبإستخدام كلا من النتائج المستخلصة من مراجعة مسودة مشروع إعداد دليل معايير التصاميم الهندسية لشبكة الطرق في ليبيا والمقارنة التي تمت بينها- المسودة – وبين الأدلة الأخرى، والنتائج المستخلصة من مراجعة مسودة مشروع إعداد دليل معايير التصاميم الهندسية لشبكة الطرق في ليبيا ومطابقتها للنتائج المتحصل عليها من الدراسة التحليلية (الاستبيان) ، خلُصت الدراسة إلى إستنتاجات وتوصيات يُرى أنها جديرة بكل إهتمام . Abstract Roads constitute the backbone around which revolves the country's unity , growth and development .Undoubtedly the presence of a developed network of roads in the country enables it to achieve its objectives and different policies , progress in roads is conducive to changing the lifestyle , raising the standard of living and contributing to the development and growth of societies.This study researched the factors and engineering design standards for roads and reviewed both the old design considerations and developing factors and basic considerations for modern design, and also addressed the primary and secondary elements of geometric design of roads and provided an overview of the impact of road design on traffic safety. Acomparison was conducted of engineering design criteria for urban roads taken from four different design guides and are respectively: Engineering design manual for roads of the U.S. state of Arizona, Engineering design manual for roads of South Africa, Engineering design manual for roads of Saudi Arabia, The project for preparing a manual of standards of engineering designs for the roads network in Libya (the section on urban roads). The study gave an assessment of the criteria applied in Libya through the examples of some sections of existing roads in the city of Tripoli, also discussed some of the problems resulting from defects in design standards and planning in the city and most important submitted proposals to address such defects.An analytical study ( questionnaire) was designed to reach the following set of goals:Identification of Libya State activity in the works of road design.What is the reference of road design in Libya?Variation of design standards for different time periods in which the design was developed.To what extent are the design criteria – currently used in Libya – are in pace with urban development?Extent of impact of design criteria on public safety for passengers,pedestrians and the environment.In conclusion, by applying the results extracted from reviewing the draft of the project for preparing the manual of criteria of engineering designs for the roads network in Libya and the conducted comparison between this draft and the other evidence and the extracted results from reviewing the draft of the project for preparing the manual of criteria of engineering designs for the roads network in Libya and the subsequent matching of the results obtained from the analytical study (questionnaire), the study reached conclusions and recommendations it deems worthwhile of due attention.
هالة محمد دحيم (2012)