A steel structural member such as a joist or beam is secured to a vertical cast concrete by a connector system including a fabricated steel receiver embedded within the wall. Embedded anchors are attached to the receiver which has front wall portions flush with the concrete wall and define a front opening. A support bracket has an attachment plate secured to the beam and a vertical plate which fits through the front opening within the receiver. The bracket is attached to the beam which is then elevated, and the vertical plate is inserted through the opening into the receiver. The beam and vertical plate are then shifted until opposite edge portions of the vertical plate are blocked by the front wall portions of the receiver. In the illustrated embodiments, the front opening and vertical plate are generally triangular, and the support bracket has a vertical or horizontal attachment plate.