ABSTRACT
A number of fatigue crackings were reported at the welded joints between vertical stiffeners and deck plates in orthotropic steel decks (OSDs) in Japan. These fatigue crackings were caused by restraining deck’s deflection by the stiffener. In order to prevent the cracking, reducing the stiffness of the stiffener top end can be a solution. For newly fabricated OSDs, the Japan Road Association recommends cutting off the top of vertical stiffeners on transverse beams. However, stiffeners with a gap under the top flange have very little vertical load carrying capacity, and could not be applied to main girders. Half-circle cutting method have been proposed as retrofitting method for existing structures. This simple method also can be applicable for new OSDs. Whereas a fillet detail is currently used for the beam to column connection of steel bridge frame piers to reduce stress concentration at the right-angle corner between beam and column. Same approach may be applicable for new OSDs. In this study, fatigue durability of the half-circle cutting detail and the fillet detail for new OSDs are verified by fatigue tests using an actual size specimen. As a result, the fillet detail showed superior fatigue durability without no fatigue crackings, while some fatigue crackings were developed in the half-circle detail.
