Germany - On behalf of the DZSF, an international consortium was commissioned in the years 2019-2023 to

Description

In 2019-2023, an international consortium was commissioned by the DZSF to develop a new dynamic load model for railroad bridges (DLM), one for passenger trains (DLM-PT) and one for freight trains (DLM-FT). Both load models consist of 20 load model trains each. The development was based on the dynamic train signatures and extensive finite element calculations. The basis for this was a comprehensive database of current and future train configurations in Europe. However, a common problem in the practice of developing new rail vehicles is that the limit values of railroad bridges for which they were designed and constructed are not sufficiently taken into account by rail vehicle manufacturers. This occasionally leads to new rail vehicles being approved or train configurations being created that can lead to high and unacceptable dynamic resonances in certain bridges. DB InfraGO therefore carries out its own complex bridge compatibility tests to determine whether and under what conditions an already approved rail vehicle may run on a specific DB InfraGO line. Consequently, there is a great need for simple methods to check whether the traffic loads caused by any rail vehicle model are covered by the dynamic load model DLM-PT\/FT or not. In practice, the calculation of railroad bridges has also shown that a transient structure calculation and evaluation with dynamic load models is very complex and time-consuming. Because the newly developed dynamic load model DLM-PT\/FT is more extensive than the old HSLM, a significant increase in the calculation effort and calculation time is to be expected. However, since there are railroad bridges that are only used by passenger trains or only with a maximum speed of 120 km\/h, 160 km\/h or 200 km\/h, the application of DLM-PT\/FT can or should potentially be simplified. The development of a graduated calculation scheme for the various load models could be very helpful in practice and should be achieved with this project. The newly developed DLM-PT\/FT was also designed for railroad deck bridges from a length of 5.0 m. However, the German railroad network has a significant number of shorter bridges where resonant excitation is possible when trains pass over. Whether the DLM-PT\/FT can also be used for these bridges or needs to be adapted is to be determined as part of an investigation in this research project. Experience also shows that some existing bridges cannot be verified mathematically according to the (currently valid) HSLM. The verification of the permissible vertical acceleration and other verifications can probably not be provided by a large number of railroad bridges when using the new DLM-PT\/FT. It must therefore be investigated and compared what effects the two dynamic load models HSLM according to DIN EN 1991-2 and DLM-PT\/FT could have on new and existing bridges in Germany.

Opportunity closing date

12 November 2024

Value of contract

to be confirmed