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H - 11 Extending the service life of prestressed railway concrete sleepers
The ballast superstructure with prestressed concrete sleepers is by far the most common type of superstructure in the German railway network. Sleepers are an integral part of the railway superstructure, transferring forces from the rail to the ballast while ensuring the track's position. Approximately 2.7 million old sleepers are removed and new ones installed on the DB network every year, which is disadvantageous both economically and in terms of sustainability. Therefore, the aim should be to extend the service life of the sleepers. The following topics arise within the scope of this project:
- Literature research on the historical development of prestressed concrete sleepers (dimensioning, earlier sleeper types and existing studies on service life).
- Comparison of sleeper dimensioning according to DIN EN 12320 and UIC 713, and the specifications in EC 2. This will be followed by a parameter study on the influence of deviations between the regulations.
- A parameter study on the influence of different boundary conditions on the load-bearing behavior/design of sleepers (condition of the ballast, condition of the rail, influence of the stiffness of the superstructure, etc.).
- Simulation of the load-bearing behavior of different types of sleepers, from manufacture to end of service life.
Contact Person:
Elias Will, M.Eng.
+49 351 463 35467
H - 10 Nachrechnung und Bewertung historischer Bemessungen von Festen Fahrbahnkonstruktionen
Die Feste Fahrbahn wird allgemein als bevorzugte Option für den Bau neuer Hochgeschwindigkeitsstrecken betrachtet. Die über 50-jährige Entwicklung dieser Technologie hat zu zufriedenstellenden Ergebnissen bei den derzeit eingesetzten Bauformen geführt. In der Entwicklungsgeschichte haben sich jedoch nicht alle Varianten als dauerhaft bewährt – in einigen Fällen kam es zu Schäden. Im Rahmen von Instandhaltungsmaßnahmen sind daher statische Nachrechnungen bestehender Konstruktionen erforderlich. Dafür müssen auch historische Bemessungsmethoden analysiert und nachvollzogen werden. Daraus ergeben sich folgende Themen und Aufgabenstellungen für Projekt- und Abschlussarbeiten (Master und Diplom), die individuell mit den Studierenden abgestimmt werden können:
- Literaturrecherche zur historischen Bemessung der Festen Fahrbahn (Deutschkenntnisse erforderlich)
- Parameterstudie zur Bemessung der Festen Fahrbahn gemäß DIN EN 16432-2 und Betonkalender 2015
- Nachrechnung historischer Feste-Fahrbahn-Konstruktionen
- Vergleichsstudie: Bemessung der Festen Fahrbahn nach DIN EN 16432 im Vergleich zu anderen Normen (z. B. Eurocode oder Model Code)
Contact:
Franz Grützmacher
+49 351 463-40412
H - 9 Numerical study of loading scenarios on slab track structures
Slab track is generally considered the preferred option for the construction of new high-speed lines. Over 50 years of development of this technology has produced satisfactory results for the designs currently in use. However, not all roadway designs have aged equally well during the development period. Some exhibit numerous damages or are in a condition that makes replacement investment worth considering. Therefore, it is of interest to determine the causes of damage to such structures. Possible impacts will be identified and compared to find out a potential cause of the damages.
This thesis deals with the following work packages:
- Comprehensive literature review on design of and loading scenarios on slab track structures
- Performing rough hand calculations to estimate the magnitude of the reations
- Investigation of possible modeling of the slab track in relation to the reations
- Determination and comparison of the results of the individual actions in the governing condition at selected points incl. determination of the maximum and minimum combinations of the actions and interpretation of the results
This investigation is carried out by means of software.
Contact:
Franz Grützmacher
+49 351 463-40412
H - 5 Influencing parameters for acoustic signals' transmission
Full title: Investigation of different influencing parameters for the transmission of acoustic signals in acoustic emission analysis (SEA)
Acoustic signals are everywhere in our life. In everyday life they can be processed by our brain to get the needed information, e.g. from a conversation. In construction, they can also be used in combination with various measurement techniques for building diagnostics. Sound emission analysis (SEA) is a non-destructive testing method that can draw conclusions about a change in the condition of the structure based on the analysis of the sound waves emitted by the structure.
For a successful building diagnosis, the quality of the measured signals is crucial, which can be influenced by many parameters. These parameters can basically be divided into three groups, the sound source in the building component, the propagation path of the acoustic signals from the source to the sensor, and the measurement system. While the first two depend on the material properties of the component, parameters from the last group, e.g. the coupling of the measurement sensor, can be influenced by the measurement setup. A good coupling not only ensures a good signal quality, but also the reproducibility of the measurements.
Within the scope of the project work, various influencing parameters such as coupling means, the contact pressure of the measuring sensor with respect to the sensor coupling are to be investigated by means of tests on small-format specimens.
Details of the task will be specified during the processing time.
Contact:
Ronghua Xu
0351 463-33776