Abstract
COMBINED METHOD OF THE RAILWAY BRIDGES DYNAMIC RESPONSE COMPUTATION ADAPTED TO DEVELOPING COUNTRIES: THE CASE OF THE SECOND BRIDGE OVER THE WOURI IN CAMEROON
Ursula Joyce Merveilles Pettang Nana*, Cedric Cabral Fandjio Yonzou and Marcelline Manjia
ABSTRACT
The modernisation of the railway sector, in particular through the introduction of new, high-performance rolling stock, as required by the UA65 strategy, implies taking into account the particularly formidable dynamic loads on existing bridges. In order to make this equipment useful and to integrate it into the development of the railway network, which is now desired to be of a high standard, a prior diagnostic analysis makes it possible to classify which of these structures should be preserved or renovated. With this in mind, this paper presents a simplified combined method for calculating the dynamic response of railway bridges in order to simulate their behaviour in service. Using the Finite Element Method (FEM), we worked with a three-layer unequal element track model and a 10 degree of freedom vehicle model. The main excitation of the system is the set of irregularities of the track taken into account by the sinusoidal PSD function of the German model. The interaction forces were expressed using the linear Kalker theory. The resulting 2D matrix equation of motion of the train was solved by Newmark's ? numerical method. The simulation carried out on the second bridge over the Wouri river, allowed on the one hand to verify the proposed method with convincing results which present limits at the level of the continuity of the railway track on firm ground (when the train is not entirely on the bridge) and on the other hand to note that existing bridges such as the Wouri river are able to receive locomotives at higher speeds (220km/h) without significant modification of the structure.
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