Interaction of an elastic foundation and structures like beams, plates and frames plays an essential role in investigating soil media in contact and impact mechanics. The solution to this interaction problem is complicated even the foundation is assumed as a linear elastic medium. E. Winkler suggested the fair representation of the foundation in 1867, and then, to bring it closer to reality, an interaction between the spring elements was introduced. In this paper, a relatively simple membrane-spring system is investigated, where an ideal gas is added under or above the membrane. In many cases, this constant pressure in the cavity modifies the solution and accuracy of the approximation is significantly increased. The cases of concentrated normal force and uniform distributed load are examined. The results of elastic half-space line displacements and the membrane displacements are presented.
The article describes the main damages of box girder viaducts constructed in Lithuania and discusses the reasons for their occurrence. Several viaducts are examined in more detail with regard to their design data and experimental results. Using finite element software "Midas Civil" the distribution of the main stresses was determined in the box and reduced girders of the Pareizgupis viaduct caused by symmetrical and asymmetrical loads. The widths of flexural cracks in the Pareizgupis viaduct are analyzed evaluating the behaviour of prestressed reinforcement suffered from corrosion. The above mentioned program was used to calculate the deflection of viaduct when damage of reinforcement is estimated. The paper examines the possibility to evaluate viaduct durability using the probability methods based on the initial investigation data.
The paper reviews the United States and Slovenian safety factor calculation methodologies and proposes a method for more accurate estimation of residual strength of bridges designed and built in Lithuania. For more detailed analysis, the main parameters and defects directly affecting the strength of the bridges were analysed in detail, and the flows of heavy vehicles, which have significantly increased for previously designed bridges, were assessed.
This article proposes to calculate the dynamic factor of bridges, not according to the empirical formulas used in the United States and Slovenian safety factor calculation methodologies, but after performing the bridge dynamic test, because the results of Lithuanian bridge dynamic tests show that the parameter strongly depends on smoothness and damage of carriageway wearing surface. In order to evaluate the suitability of the Lithuanian bridge safety factor calculation methodology proposed in this article, a real bridge was selected, and its safety factors calculated according to the above mentioned and proposed methodology and the results obtained were compared.
The article examines the effect of dynamic loads on crack width of decks of prestressed reinforced concrete frame (boxgirder) viaducts. The experimental measurement of the changes in width of vertical cracks of Pareizgupis viaduct resulting from the loads of moving heavy weight vehicles was made. During testing, four-axle vehicles with weights of around 40 tonnes were used and they were driven over the viaduct deck at the speed of 20-40 km/h. The stresses in prestressed reinforcement were analysed, calculated and compared to the results obtained during testing. Having evaluated theoretically the elastoplastic operation of concrete, the width of a vertical crack was measured in the middle part of the viaduct.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.