PSI - Issue 38

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2021) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2021) 000 – 000 Available online at www.sciencedirect.com

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

Procedia Structural Integrity 38 (2022) 428–446

FATIGUE DESIGN 2021, 9th Edition of the International Conference on Fatigue Design FATIGUE DESIGN 2021, 9th Edition of the International Conference on Fatigue Design Fatigue evaluation of beam cope holes in the web coinciding with thickness transition in the flange Fatigue evaluation of beam cope holes in the web coinciding with thickness transition in the flange

Jacques BERTHELLEMY Steel Bridges Engineering Expert at Cerema, France Chairman of TC50 European Committee (Lighting columns) Jacques BERTHELLEMY Steel Bridges Engineering Expert at Cerema, France Chairman of TC50 European Committee (Lighting columns)

Abstract Under a large amount of heavy traffic, the fatigue damage of steel bridges is prone to occur, leading to serious disasters. The choice of the right economic features for the details is important. The cope hole feature is economic and allows an easy control of the butt weld of the flange. For this reason, it is still used in many countries for the welded joints on site. In other countries, is not recommended for fatigue or completely forbidden. Therefore, rational rules are needed to determine whether this detail is appropriate or not for the use in a new bridge construction in regard with the supported traffic. In France a web cope hole concomitant with a thickness transition in the bridge’ s flange was experimentally used in the '70s and after that not recommended. However, the lack of specific rules in the ECCS recommendations edited during the 90’s or in the present Eurocodes has induced many designers to think wrongly after 1987 that it was acceptable again. Therefore, this paper proposes rules to calculate the cope hole feature regarding fatigue, in the conditions that occur in the bridge beams. Stress concentration factors are proposed to evaluate the effect of the thickness transition in comparison with the fatigue strength category of 71 MPa which is only adapted when there is no thickness transition and only a longitudinal stress in the beam at the hot point. The principal aim is to evaluate, and if needed assess and repair motorway bridges already in service because of the shortcomings of the present Eurocodes. The proposed rules can be used to evaluate, assess and repair existing bridges. Their assessment and reinforcement has to start with the right evaluation of such a crucial and frequent detail. The proposed rules will to decide today the appropriate repair works in order to avoid degradation due to fatigue cracks. Abstract Under a large amount of heavy traffic, the fatigue damage of steel bridges is prone to occur, leading to serious disasters. The choice of the right economic features for the details is important. The cope hole feature is economic and allows an easy control of the butt weld of the flange. For this reason, it is still used in many countries for the welded joints on site. In other countries, is not recommended for fatigue or completely forbidden. Therefore, rational rules are needed to determine whether this detail is appropriate or not for the use in a new bridge construction in regard with the supported traffic. In France a web cope hole concomitant with a thickness transition in the bridge’ s flange was experimentally used in the '70s and after that not recommended. However, the lack of specific rules in the ECCS recommendations edited during the 90’s or in the present Eurocodes has induced many designers to think wrongly after 1987 that it was acceptable again. Therefore, this paper proposes rules to calculate the cope hole feature regarding fatigue, in the conditions that occur in the bridge beams. Stress concentration factors are proposed to evaluate the effect of the thickness transition in comparison with the fatigue strength category of 71 MPa which is only adapted when there is no thickness transition and only a longitudinal stress in the bea at the hot point. The principal aim is to evaluate, and if needed assess and repair motorway bridges already in service because of the shortcomings of the present Eurocodes. The proposed rules can be used to evaluate, assess and repair existing bridges. Their assessment and reinforcement has to start with the right evaluation of such a crucial and frequent detail. The proposed rules will to decide today the appropriate repair works in order to avoid degradation due to fatigue cracks. Keywords: Road bridges, Fatigue design, cope hole, stress concentration factor. © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2021 Organizers

Keywords: Road bridges, Fatigue design, cope hole, stress concentration factor.

2452-3216 © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2021 Organizers 10.1016/j.prostr.2022.03.044 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2021 Organizers 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2021 Organizers