ce/papers最新文献

The newly proposed high-speed rail in Czech Republic creates a set of new challenges for engineers in design overall. In this case, the most significant challenge was to design a viaduct over several obstacles due to the crossing of Special Area of Conservation (SAC), part of Natura 2000. This aims to limit impacts in short-term, during construction and more importantly in the long term. Construction of the viaduct will mitigate an impact to the natural surrounding area, whilst allowing immigration of its natural habitats. Nevertheless, the viaduct design and operational speeds will reach 320 km/h with possible raising to 350 km/h limit, with minimal impact within the area.

Initial length of the viaduct was over 1 300 m and the main requirement given by an infrastructure manager was to design a viaduct without railway expansion joints. Due to such a long distance, the viaduct had to be separated into several dilatation segments in order to avoid the use of rail expansion joint. The most susceptible parts of SAC were in proximity of the river Šatava and surrounding wetlands. This area created an obstacle, which had to be crossed by a long span avoiding the implementation of bridge piers. Poor geological conditions close to the watercourse had to be taken into consideration for design of pier foundation, therefore the span had to be shortened to a compromised length.

The final design of the viaduct consists of 16 segments, of which 14 are continuous segments and 4 are single spans. Overall, there are 29 spans over the length of the viaduct. Construction method of incremental launching had been chosen to reduce the short-term impact in the SAC.

The new railway line connecting Luxembourg and Bettembourg crosses the A3 highway at a steep angle (19.5°) with the bridge called OA14.

The designed bridge is a bowstring structure with a single span of 186.85 meters. The bridge deck consists of two lateral metal box girders acting as a chord. The deck is a transversal filler beam, with spherical voids and lightweight concrete to reduce the structure's weight.

The bridge features two inward-inclined arches at 9°, which are doubled and serve as trusses. This significantly increases the stiffness of the arch whilst keeping the silhouette elegant. The deck follows the curved track alignment, the arches remain straight. Two times 12 hangers connect the arches to the girders, they are made of CHS profiles of S450H quality. This article gives an overview of the structure and its construction. It then gives a more detailed insight in the design of the hangers, especially the hanger-girder connections.

A ramp structure with a length of 588 m was planned in the area of the Nuremberg East interchange between the A9 and A6 highways. The bridge structure is an extradosed bridge, which represents an unusual technical and design solution for a ramp structure in Germany for reasons of maintaining traffic. The structure is preassembled in incremental sections, fitted with the cables and incrementally lengthwise inserted. In addition to the design and assembly, the article also reports on structural design aspects.

Assessing rope force in bridge structural health monitoring, particularly for shorter lengths, poses challenges. The vibration method, commonly utilized for taut strings, yields inaccurate results for short ropes due to neglecting bending stiffness. To address this, the differential equation of lateral vibration of a prismatic beam possessing bending stiffness EI, evenly distributed mass m under the tension force N is solved approximately and numerically using FEM for greater accuracy. Nonlinear fitting via the Gauss-Newton aids in refining results. Laboratory experiments, varying axial forces and rope characteristics, validated these methods, offering recommendations for improved accuracy.

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.