Abstract: A straight elongate structural member, and a structure incorporating such members, capable of rigid mounting at its ends into a reticulated structure to form one of a plurality of structural members forming that structure, the member comprising a straight elongate element serially interconnected with a load responsive means which at working loads axially applied to the member is rigid and which at a desired predetermined load, in excess of the working loads, axially applied to the member becomes plastically deformable the predetermined load being less than the critical load of the member when rigidly supported at its ends.