ce/papers最新文献

Steel bridge designers and erectors primarily rely on approximate methods, such as 1D line girder analyses and 2D grid analyses. For curved or skewed bridges, this can give erroneous indications of the structure's true behaviour. Refined methods of analysis, such as 3D shell modelling, aim to bring a significant change in the practice of bridge engineering. By moving the industry away from simplistic design assumptions, refined analysis methods lead to more accurate, less conservative results, which in turn brings true benefits such as improved structural safety and increased economy. In this paper, several case studies on curved plate girder and tub girder bridges are presented, which cover the full bridge life cycle, from erection of the steel structure and placement of the concrete deck, down to live load analyses using influence surfaces and load rating. The case studies will be modelled with mBrace3D, a dedicated FEA software for curved steel bridges.

Steel structures are typically engineered for the upper range of the steel toughness-temperature curve. To account for the reduction in toughness properties within the temperature transition range, additional safety assessments are necessary. These assessments rely on fracture mechanics considerations and enable the selection of an adequate steel material to prevent brittle fracture. Considering this context, recommendations were already put forth in 2011 to govern the appropriate choice of steel grades for bearing components. However, these recommendations are no longer entirely current in light of more recent findings. As a result, the German Centre for Rail Traffic Research has called a research project with the aim to formulate proposals to expand the regulatory framework related to suitable material selection, aimed at preventing brittle fracture in bridge bearings.

The utilization of currently measured geometric data for analysis of arch bridges and their stability is discussed. The presented contribution follows a set of research activities focused on real values of geometric imperfections of a steel bow-string arch bridge using 3D scanning. Relatively new railway arch bridge with span 124.8 m is discussed. Deviations from the theoretical design shape of the arch were recorded during the erection stage and after a proof-load test of the bridge, as well. Thus, it was possible to observe if and how the geometric imperfection changes during construction. Numerical models were created to perform geometrically nonlinear analysis. Both theoretical and real imperfections obtained by 3D scanning were considered in the analysis to compare and quantify the influence of the actual deformed shape. Finally, the obtained data, their comparison, the applicability of the presented methods, and possible pitfalls of the procedure are discussed.

The railway bridge in Prague under Vyšehrad is a steel riveted structure with a lower deck from 1901 connecting the right and left banks of the Vltava River. The bridge is double-track and is located on a national track included in the TEN-T system. This is the transit corridor Nuremberg – Pilsen – Prague – Brno – (Vienna, Bratislava, Poland). It is therefore one of the busiest railway bridges in the Czech Republic. The bridge is a cultural monument.

At the moment, it is also the best-known and most discussed railway bridge in the Czech Republic. The bridge has been in service for more than 120 years and its expected lifespan has long been exceeded. The railway needs to increase the track capacity. At the same time, it is being discussed what to do with the heritage-protected bridge. Repair? Replace? Shift? These are the questions and challenges facing the Railway Administration.

Footbridges with prestressed concrete deck, which are suspended on steel arch ribs, are described in terms of the structural arrangement, static function and erection. These bridges create stiff structural systems which guarantee the bridges' favourable dynamic response. While steel arch ribs allow easy erections, the concrete deck guarantees structural integrity. The footbridges are structurally efficient, they are light and transparent, corresponds to the scale of the landscape and all structural members have human dimensions. They were erected with a minimum impact on the environment. Their structural arrangement is illustrated on examples of four bridges.