This paper is a theoretical investigation into the effect of a rivet-attached stringer on the stress concentrations in a thin elastic sheet with a crack. The sheet and stringer are loaded (at infinity) by a uniform tensile stress parallel to the stringer. The sheet contains a finite crack perpendicular to the stringer. The problem is formulated in terms of an infinite set of algebraic equations for the unknown rivet loads which are truncated and then solved on the IBM 7094 digital computer. The results are used to calculate the effect of the stringer on the strength of the stress intensity at the crack tip.