Dynamic analysis of a bridge structure exposed to high-speed railway traffic
Authors
Bucinskas, Paulius ; Agapii, Liuba ; Sneideris, Jonas
Term
4. term
Education
Publication year
2015
Submitted on
2015-06-04
Pages
159
Abstract
Højhastighedstog gør jernbanebroers dynamiske adfærd vigtig at forstå, fordi vibrationer og deformationer bliver større og sværere at forudsige, jo højere hastighederne er. For at kunne forudsige denne adfærd udvikles beregningsmodeller med stigende kompleksitet. Først analyseres en simpelt understøttet bjælke, der påvirkes af en bevægende konstant kraft, med både analytiske metoder og finite element-metoder. Dernæst indføres et køretøj i modellen på flere måder: som en bevægende masse, som et system med én frihedsgrad og som et system med flere frihedsgrader (forskellige bevægelsesmuligheder). Herefter udvides modellen til tre dimensioner ved hjælp af tredimensionelle bjælkeelementer. Den mest avancerede model omfatter også undergrunden under broen og beskriver både køretøj–struktur-interaktion og struktur–jord–struktur-interaktion, som beskrevet i artiklen Numerical modelling of dynamic response of high-speed railway bridges considering vehicle-structure and structure-soil-structure interaction. De forsøg, der bruges til at validere modellerne ved sammenligning med en forsøgsmodel i lille skala, præsenteres i artiklen Experimental validation of a numerical model for three-dimensional railway bridge analysis by comparison with a small-scale model. Forsøgene viser, at korrekt modellering af køretøj–spor-systemet og undergrunden er afgørende for at analysere broens dynamiske opførsel. Den foreslåede beregningsmodel giver en forenklet løsning til forløbige beregninger og tager samtidig højde for de vigtigste bidrag til vibrationer og deformationer i bro–undergrund-systemet.
As train speeds increase, railway bridges experience stronger and harder-to-predict vibrations and deformations, making their dynamic behavior a key concern. To understand and predict this behavior, we develop computational models of increasing complexity. We begin with a simple case: a simply supported beam subjected to a moving constant force, analyzed using both analytical methods and finite element methods. We then add a vehicle to the model in several ways: as a moving mass, as a single-degree-of-freedom system, and as a multi-degree-of-freedom system (representing one or several modes of motion). Next, we extend the model to three dimensions using three-dimensional beam elements. The most advanced model also includes the subsoil beneath the bridge and accounts for vehicle–structure interaction and structure–soil–structure interaction, as described in the paper Numerical modelling of dynamic response of high-speed railway bridges considering vehicle-structure and structure-soil-structure interaction. Tests used to validate the models by comparison with a small-scale experimental model are presented in the paper Experimental validation of a numerical model for three-dimensional railway bridge analysis by comparison with a small-scale model. These experiments show that realistic modeling of the vehicle–track system and the subsoil is crucial for analyzing the structure’s dynamic behavior. The proposed computational model provides a simplified tool for preliminary calculations while capturing the most significant contributors to vibrations and deformations in the bridge–subsoil system.
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