The present invention contemplates a reinforced concrete beam comprising a longitudinally extending concrete beam including a plurality of I-beam receptacles spaced apart along the length thereof and wherein each of the I-beam receptacles has a depth and a width to accommodate an end of an I-beam having an upper and lower metal flange of about equal width and a central metal web connecting the flanges, and in the building a hard rubberlike elastomer spacer is disposed between the I-beam receptacles and an end of an I-beam. The beams further include one to three longitudinally extending metal rods disposed underneath the I-beam receptacles and surrounded by concrete.