The Dynamic Load Factor (DLF) is defined as the ratio between the maximum dynamic and static responses in terms of stress, strain, deflection, reaction, etc. DLF adopted by different design codes is based on parameters such as bridge span length, traffic load models, and bridge natural frequency. During the last decades, a lot of researches have been made to study the DLF of simply supported bridges due to vehicle loading. On the other hand, fewer works have been reported on continuous bridges especially with skew supports. This paper focuses on the investigation of the DLF for a highly skewed steel I-girder bridge, namely the US13 Bridge in Delaware State, USA. Field testing under various load passes of a weighed load vehicle was used to validate full-scale three-dimensional finite element models and to evaluate the dynamic response of the bridge more thoroughly. The results are presented as a function of the static and dynamic tensile and compressive stresses and are compared to DLF code provisions. The result shows that most codes of practice are conservative in the regions of the girder that would govern the flexural design. However, the DLF sometimes exceeds the code-recommended values in the vicinity of skewed supports. The discrepancy of the DLF determined based on the stress analysis of the present study, exceeds by 13% and 16% the values determined according to AASHTO (2002) for tension and compression stresses respectively, while, in comparison to BS5400, the differences reach 6% and 8% respectively.
Background: Numerous methods have been described for achievement of Intermaxillary fixation in the treatment of fractures of facial skeleton. Conventional methods like Erich arch bars and eyelet wires are currently the most common methods for achieving intermaxillary fixation (IMF), however, they have their own disadvantages. Since 1989, IMF using intraoral self-tapping IMF screws has been introduced for treatment of mandibular fractures. The aim of this study was to evaluate the efficacy, advantages, disadvantages and potential complications associated with using of self-tapping IMF screws in the treatment of mandibular fractures. Material and Methods: Twenty patients with favorable mandibular fractures, attended to Oral and Maxillofacial
... Show MoreIt is commonly known that Euler-Bernoulli’s thin beam theorem is not applicable whenever a nonlinear distribution of strain/stress occurs, such as in deep beams, or the stress distribution is discontinuous. In order to design the members experiencing such distorted stress regions, the Strut-and-Tie Model (STM) could be utilized. In this paper, experimental investigation of STM technique for three identical small-scale deep beams was conducted. The beams were simply supported and loaded statically with a concentrated load at the mid span of the beams. These deep beams had two symmetrical openings near the application point of loading. Both the deep beam, where the stress distribution cannot be assumed linear, and the ex
... Show MoreThe aim of this investigation is to evaluate the experimental and numerical effectiveness of a new kind of composite column by using Glass Fiber‐Reinforced Polymer (GFRP) I‐section as well as steel I‐section in comparison to the typical reinforced concrete one. The experimental part included testing six composite columns categorized into two groups according to the slenderness ratio and tested under concentric axial load. Each group contains three specimens with the same dimensions and length, while different cross‐section configurations were used. Columns with reinforced concrete cross‐section (reference column), encased GFRP I‐section, and encased steel I‐section were adopted in each
Many drilling problems (lost circulation, hurdle in running casing, poor cement jobs, high torque and drag and the necessity of re-drilling and, mechanical stuck caused by cutting accumulation in the wellbore) can be avoided by good hole cleaning during drilling operation especially in directional wells.
In this experimental work, the cutting transport ratio (CTR) in hole inclined (60 degree) from vertical was estimated by using three values of drilling mud viscosities, three annular velocities, two types of cuttings size and two rotation speed of inner pipe (RPM). Note that the rig consisted from PVC outer casing 4 1/2 inch as OD diameter and inner dri
The present study tackles the scientific model and the mechanisms of operating in the formation of the image of the artistic work to create a scene that cares for the aesthetic decoration through raw and techniques and employing them to express the aesthetic values that care for what is not familiar and deviation from the familiar in the visual exhibition and the care for the employment of the technical abilities, lighting, and sound as well as the employment of multiple materials. The research presents the objectives of his study in the exhibition hall of Natural History Museum (University of Baghdad) to create an aesthetic and expressive state at the same time. Then, in the theoretical framework the researcher traces the experiments of
... Show MoreThe corrosion protection of low carbon steel in 2.5 M HCl solution by kiwi juice was studied at different temperatures and immersion times by weight loss technique. To study the determination of the optimum conditions from statistical design in evaluation of a corrosion inhibitor, three variables, were considered as the most dominant variables. These variables are: temperature, inhibitor concentration (extracted kiwi juice) and immersion time at static conditions.
These three variables are manipulated through the experimental work using central composite rotatable Box – Wilson Experimental Design (BWED) where second order polynomial model was proposed to correlate the studied variables with the corrosion rate o
... Show MoreElectrical distribution system loads are permanently not fixed and alter in value and nature with time. Therefore, accurate consumer load data and models are required for performing system planning, system operation, and analysis studies. Moreover, realistic consumer load data are vital for load management, services, and billing purposes. In this work, a realistic aggregate electric load model is developed and proposed for a sample operative substation in Baghdad distribution network. The model involves aggregation of hundreds of thousands of individual components devices such as motors, appliances, and lighting fixtures. Sana’a substation in Al-kadhimiya area supplies mainly residential grade loads. Measurement-based
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