Local stresses in webs of crane runway girders: Tests and numerical calculations

The design of crane runway girders is strongly affected by the local stresses due to wheel loads (mainly fatigue design, but also web buckling). A realistic approach of these local stresses, particularly the vertical direct stresses σz at the web top, is very important for economic design. In this paper firstly a summary of formulae in literature and in relevant international design standards is given. These formulae are based on very limited tests in the past, which are also mentioned. In the main part of this paper new test results for local stresses in webs due to vertical wheel loads for crane runway girders with I-section and box section are given, also including different connections with the crane rails (with/without welds between rail and girder flange and cases with no rail). Centric loading was tested, but also eccentric loading with different eccentricities, leading to additional web bending out of plane. For all tests, accompanying comprehensive Finite Element analyses were conducted. These FE-models are also presented and their results are compared with the test results and with the predictions of design formulae, used in practice. Finally, additional numerical investigations are presented, dealing with the effects of different contact properties between rail and girder flange.