Load-bearing behaviour of reinforced large web openings in steel design

• Applicant: Professor Dr.-Ing. Mathias Euler
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565966528

Subject | The steel structures of buildings and civil engineering works (such as steel bridges) consist to a large extent of girder structures that are made of welded plate girders with (very) thin, slender webs and comparatively strong chords in order to conserve resources. The girder webs are predominantly flat, but can also have a profile (corrugated web, trapezoidal web). In terms of serviceability, the webs of plate girders make it difficult to arrange pipes, cables and ducts that are necessary for the structure's function. For this reason, web openings are a common measure which, with appropriate stiffening of the opening (reinforcement), should only slightly reduce the efficiency of the construction method. Problem | The arrangement of large web openings changes the stress distribution within the girder and thus significantly influences its load-bearing capacity and stiffness, especially if the web openings are insufficiently reinforced. It is therefore a necessary prerequisite for the efficiency of modern steel structures, especially lightweight structures, that the load-bearing behaviour of plate girders with large stiffened web openings is fundamentally understood and can be described quantitatively. There are empirical studies, numerical analyses and simplified calculation models in the literature, but most of these only consider one type of web and/or one type of loading. To date, there is no closed, generally valid model for the load-bearing behaviour of reinforced large web openings. Research objective | The research project aims to conduct fundamental theoretical and experimental research into the load-bearing behaviour of reinforced large web openings. The aim is to develop a generally valid analytical model that is independent of the type of girder web (flat, corrugated etc.), the shape of the web opening (circular, rectangular) and the type of girder loading. The model to be developed as part of such basic research should be a starting point for downstream future application-oriented research projects (e.g. IGF, Zukunft Bau), in which design rules for future technical building regulations are derived. Work programme | The research objective is to be achieved through analytical, numerical and experimental investigations in a work programme with five work packages. An essential part of the work programme consists of 72 ultimate load tests on girders with flat, corrugated and trapezoidal or triangular profiled webs. These tests serve as a validation basis for the numerical and analytical investigations.

• DFG Programme: Research Grants