The present disclosure relates to a steel joist assembly for use in association with a concrete slab and being adapted to form a composite steel joist including a steel joist and a pair of end connectors. The steel joist has a top portion with a generally planar top surface and a planar web generally orthogonal to the generally planar top surface. An end connector is attached at each end of the steel joist. Each end connector has a strut and a diagonal member. The strut has a generally planar bottom surface which is attached to a portion of the generally planar top surface of the steel joist and the diagonal member is attached at one end thereof to the strut and at the other end thereof to a portion of the planar web of the steel joist.