Adhesive improvement of fatigue damages for steel construction structures

Prof. Dr.-Ing. Christian Schuler
Civil Engineering, Department 02

Fatigue stress is often a major challenge in the design of steel components. The service life of cyclically stressed steel structures, such as bridges, cranes, conveyor systems, masts or wind turbines, is determined by the fatigue strength of the design details used, which is classified by the so-called notch cases. The design is usually based on the application of the nominal stress concept, based on the fatigue strength catalogued Δσc for the specific notch class of the design detail.

However, for some years now there has been an increase in damage to steel structures stressed by fatigue. In national bridge construction, this can be seen, among other things, in an increasing deterioration of the condition grades of the bridge structures. Above all, conditions deviating from the original design, such as an extension of the operating time, changing external conditions (increased traffic volume, increased freight traffic performance) as well as production or execution-related errors in the construction or strengthening of the structures can lead to overstressing of the above-mentioned load-bearing structures and thus to damage.

In recent years BASt, among others, has carried out a number of investigations into fatigue damage and possibilities for the permanent strengthening of bridge components. The large number of investigations shows the necessity of new rehabilitation concepts and methods in the context of building maintenance.

This is where this research project comes in: Adhesive concepts for the permanent strengthening and evaluation of high fatigue stressed notch cases of steel structures are developed and examined for their feasibility in order to reduce the stress level at the critical points and thus extend the service life of the structures.