An attachment member formed from sheet material configured to connect a wall to a curved roof of a building structure. The attachment member includes at least two segments: a first segment having a flat center portion and a pair of walls extending perpendicular to the center portion in cross section, the pair of walls defining a recess oriented in a direction perpendicular to the center portion, wherein the recess is adapted to accommodate a portion of a wall of a building structure; and a second segment extending from one of the walls of the first segment, the second segment being oriented in a same plane as the flat center portion of the first segment in cross section, the second segment including a longitudinal rib, the longitudinal rib protruding in cross section from the second segment, the longitudinal rib being adapted to mate with a rib of a curved building panel. Building structures made using such attachment members and an attachment member forming system are also described.