At a beams-to-column joint connection of two beams to a column, in which the joint connection comprises both a gravity load-carrying connection and a moment-resisting connection, there is added a beam-to-beam connection across the column, using two gusset plates, facing each other, on opposite sides of the joint connection. The gusset plates, which are not connected to the column in a moment-resisting connection, connect the two beams, in a tension and moment-resisting connection with respect to each other, by longitudinal welds between the gusset plates and the beams, and provide the capability of withstanding disastrous events, including loss of column support and/or loss of integrity of the beams-to-column joint connection and severe torsional and lateral inelastic deformation due to direct blast pressure. When subjected to such violent conditions and upon loss of column support, and, the likely loss of integrity of the beams-to-column joint connection, the two beams and two gusset plates provide independent beam-to-beam structural continuity, causing the two beams to act as one long beam, or, in other words, a “double-span” condition is created. Such beam-to-beam connection is capable of carrying the tension, torsional and moment loads placed upon the beams, to the ultimate capacity of the beams. Inasmuch as a gusset plate is disposed on each side of the beams-to-column joint connections, substantial shielding of those connections against blast and impact forces is also achieved.