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Issue 3: Sep.-Dec. 2022

Issue 3: Sep.-Dec. 2022

Published online on January 2023

Efficiency of Dynamic Relaxation Methods in Solving Bending Plates

Hossien Estiri, Amir Baghban

Abstract: The bending plate structure has been solved by several researchers with explicit dynamic relaxation (DR) methods. These techniques are based on the different assumptions. The main purpose of this paper is investigation the merit of various procedures for elastic analysis of bending plates. Therefore, sixteen known algorithms are employed. It should be reminded that the difference between these tactics is how to find the fictitious parameters of DR. Several examples of bending plates, with various shapes, are analyzed. According to number of iteration and duration analysis, the studied approaches of DR are graded. Finally, the ranking of these methods is found. The numerical results indicate the appropriate efficiency of Underwood and nodal damping processes for linear analysis of bending plates.

International Journal of Bridge Engineering, Vol. 10, No. 3, 2022: pp. 1-36

Critical Review and Modelling of the Construction Sequence and Loading History of the Collapsed Morandi Bridge

Andrea Orgnoni, Rui Pinho, Matteo Moratti, Nicola Scattarreggia, Gian Michele Calvi

Abstract: The Viaduct over the Polcevera River, designed by Riccardo Morandi, was a very strategic and important bridge, built in Genoa (Italy) in the mid-60s. In addition to being a renowned engineering work, due to a very innovative design at that period, the bridge was also considered as one of the symbols of the city. On the 14th of August 2018, however, a portion of this bridge suffered a catastrophic sudden collapse that caused 43 casualties. In order to be able to understand, within the context of the necessary numerical forensic investigations, the stress state to which the bridge was subjected to at the moment of collapse, it is first necessary to reproduce both its construction sequence, as well as the loading history the structure was subjected to throughout its life. This work is thus focussed on such task, as well as on showing the differences between the construction sequence that had been initially envisaged at the design stage and the one that was then actually followed during construction. The analyses carried out highlight how important is the correct modelling of the construction sequence, showing how the use of unknowingly incorrect inputs, may give rise to erroneous stress state estimations, which can then in turn mislead post-collapse forensic studies. In addition, the changes in permanent loading (e.g. addition of asphalt layers, replacement of road barriers) and time-dependent effects (e.g. concrete creep and prestress relaxation) over the course of the 51 years of life of the structure, are also scrutinised and discussed, with a view to try to reproduce as accurately as possible the stress state conditions of the structure at the time of its failure.

International Journal of Bridge Engineering, Vol. 10, No. 3, 2022: pp. 37-62

Sustainable Behaviour of Bridge Column Subjected to Three-Dimensional Ground Excitation

Raghda Adel Gad, Ahmed Farghal Maree, Bahaa Sharaf Tork

Abstract: Infrastructure is the core of smart cities. Maintaining longevity and sustainable performance is essential in the planning and design of new cities. This cannot be achieved without confident design of infrastructures to resist hazard loads like earthquakes. Numerous cases of substantial damages have been reported in bridge columns affected by the three-dimensional (3D) ground motion excitation. Horizontal ground motion excitations have been studied extensively and considered in the design process whereas the vertical component of earthquake excitation has generally been neglected or underestimated in analysis and design. This paper presents analytical study using ABAQUS finite element analysis software for investigation of vertical motion effects on reinforced concrete (RC) bridge column. In this study, nonlinear time history analysis was performed for two cases of loading: horizontal ground motion as well as horizontal and vertical ground motions. The vertical component of the ground motion will increase the level of response and the amount of damage sustained by a highway/railway bridge. Vertical motion generates fluctuating axial forces compression and tension in the columns, which cause magnification of the hysteresis loops.

International Journal of Bridge Engineering, Vol. 10, No. 3, 2022: pp. 63-71

Introduction and Literature Review on Atbara Water Current Turbine Mounted on Buoyant Decks Plates

Osama Mohammed Elmardi Suleiman Khayal

Abstract: The motivation that led to the writing of the present paper is the necessity to exploit the high velocity energy of River Nile that obtained when River Atbara meets River Nile in Atbara city, which is located in River Nile State. At the junction of the two rivers, high velocity energy is available and therefore, could be utilized in different applications. A suitable energy converter is needed to utilize this abundant energy. The water current turbine unit is mounted on buoyant decks plates' pontoon. This review paper is a continuation of a series of researches executed by the Faculty of Engineering and Technology Atbara – Nile Valley University to utilize the hydraulic energy of River Nile and try to convert it into a suitable form of energy for the general good of the simple citizens of River Nile and Northern States. The review study includes general introduction to water current turbines; literature review; theories of aerofoils, which include aerofoils definitions, aerofoils terminologies, geometrical parameters of aerofoils, aerofoils types; generation of lift and drag; and conclusions.

International Journal of Bridge Engineering, Vol. 10, No. 3, 2022: pp. 73-83

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