عدي محمد عباس البوذبحك

This paper presents a work to validate formulae for maximum stress and deflection in glass panels by physical testing. The formulae were generated from finite element modelling using ANSYS. The physical testing revealed that unless the glass panel is restrained in position at the support points, membrane action is not developed and greater stresses and deflections are developed than predicted. Designer’s should therefore take a pessimistic view of support conditions and ignore the benefits of membrane action. Further physical testing is suggested, so that better representations of real glass panel support systems can be investigated

As a computer technique, Artificial Neural Networks (ANNs) have expanded in use with engineering fields. ANNs have been used in many civil engineering problems and some of them were used in the design of concrete structural elements and have shown a good degree of success. This paper presents an ANN model for the strength design of reinforced-concrete hydraulic structure according to the requirements of the Engineering Manual 1110-2-2104. Structural design is a sequential process needs iteration, assumption, checking the limits, ...etc, and that can be programmed with some judgments of the designer. 288 cases of design samples have been calculated using excel sheets and Microsoft visual basic programming language. 200 samples of design randomly selected have been used for training of (4-10-10-2) ANN model. 50 samples have been selected for validation, and 38 for prediction processes. The predicted design outputs were the thickness of hydraulic concrete section and corresponding steel reinforcements. Visual Gene Developer software of ANN prediction for general purposes has been used with a feed-forward neural network with a standard back-propagation learning process. The suggested artificial neural network model has predicted the output data of design for concrete sections, and the results have shown a satisfactorily match with the actual output data of design.

The rising need for utilizing alternative construction materials has promoted use timber as a construction material. Composite elements from available timber and other strengthening materials can be produced in order to find elements have strength similar to those of bigger size. Six timber beams have been strengthened with two steel channels and then tested. A finite element method was undertaken besides experimental tests as investigation methods. This study is conducted to investigate the bending behavior of composite timber-steel beams and also to enrich the research field regarding the investigation of such beams. According to the experimental tests, it was evident that both of the timber cracks and steel channels bond arrangement have strongly affected specimens’ behavior. The increases in the bond between the two channels have increased the load carrying capacity and the ductility for the specimens. Finite element method has showed a good tool in investigating the composite timber-steel beams behavior.

In although many experimental investigations were conducted on FRP reinforced concrete beams with rectangular section, there has been very little research into the behavior of concrete flanged beams reinforced with FRP bars. This study aims at investigating the deflection of HSC I-beams reinforced with CFRP bars, both experimentally and analytically. At the service load level, most of the previous theoretical approaches underestimate the deflection. So, this paper reassess most of the previous models and propose a new approach for deflection prediction. A new equation for estimating the effective moment of inertia of CFRP reinforced concrete beam based on the analytical and experimental results was proposed. In the experimental part of the study, eight I-beam specimens were manufactured and tested. The effects of reinforcement ratio and the level of loading on the effective moment of inertia are taken into account. The proposed equations are compared with different code provisions and previous models for predicting the deflection of FRP reinforced concrete beams.

Abstract Fiber Reinforced Polymer (FRP) bars are anisotropic in nature and have high tensile strength in the fiber direction. The use of High-Strength Concrete (HSC) allows for better use of the high-strength properties of FRP bars. The mechanical properties of FRP bars can yield to large crack widths and deflections. As a result, the design of concrete elements reinforced with FRP materials is often governed by the Serviceability Limit States (SLS). This study investigates the short-term serviceability behavior of FRP RC I-beams. Eight RC I-beams reinforced with carbon-FRP (CFRP) and four steel RC I-beams, for comparison purposes, were tested under two-point loading. Deformations on the concrete and crack widths and spacing are measured and analyzed. A discussion on the main aspects of the SLS of FRP RC is introduced. The service load that fulfills the serviceability requirements, at a cross-section level, ranges between 0.27 and 0.38 times the ultimate load for sections dimensioned to fail in concrete crushing. The determinant criterion is the deflection limitation. البوليمرات المسلحة بالألياف (FRP) في طبيعتها متباينة الخواص في الاتجاهات المختلفة وتملك قوة شد عالية باتجاه الالياف. أن استخدام الخرسانة عالية المقاومة (HSC) مع قضبان البوليمرات المسلحة بالألياف يسمح بالاستفادة القصوى من مقاومة الشد العالية لقضبان البوليمرات المسلحة بالألياف. أن الخواص الميكانيكية لقضبان البوليمرات المسلحة بالألياف قد تؤدي الى تشققات عريضة وهطول كبير. وكنتيجة لذلك, فان تصميم العناصر الخرسانية المسلحة بمواد البوليمرات المسلحة بالألياف غالبا ما تتحكم بها حالات حد الخدمة (SLS). هذه الدراسة تبحث في سلوك العتبات الخرسانية المشفه والمسلحة بقضبان البوليمرات المسلحة بالألياف ولحد الخدمة القصير الامد. تم فحص ثمانية عتبات خرسانية مشفه مسلحة بقضبان البوليمرات المسلحة بالألياف الكربونية واربعة عتبات خرسانية مشفه مسلحة بحديد التسليح لغرض المقارنة, تحت نقطتين للتحميل. التشوهات في الخرسانة وعرض التشققات والمسافات بينها تم قياسها و تحليلها. تم عرض دراسة حول اهم سمات حالة حد الخدمة (SLS) للعناصر المسلحة بالبوليمرات المسلحة بالألياف. ان اقصى حمل يلبي متطلبات حد الخدمة يتراوح بين 0.27 و 0.38 قيمة حمل الفشل العملي بالنسبة للنماذج المصممة لتفشل بتهشم الخرسانة. ان المحدد السائد كان محدد الهطول.