A lower connector includes a lower connector hollow body, a pair of lower connector bosses coupled to the lower connector hollow body, and a pair of lower connector arms coupled to the lower connector bosses. A connector assembly includes an upper connector coupled to a lower connector and a gusset plate sandwiched between the upper and lower connectors.

Building or structural panels may be joined, such as to form walls or floors. The panels may be connected in various orientations via one or more connectors. The connectors may mount to anchors associated with the panels. The panels may have outer skins located over an expanded core comprising a matrix of supporting elongate members and voids or openings, with the anchors located at edges of the panels.