Abstract: A structure for the support of equipment which may be struck by a moving body, the structure comprising a plurality of relatively rigid members and a plurality of frangibly connected joints connecting the plurality of relatively rigid members, each frangibly connected joint including a frangible region oriented with its longitudinal axis in the horizontal direction, the frangible region comprising a relatively brittle material of high strength, wherein the yield point of the material and its ultimate tensile strength are relatively close, to primarily shear under extraordinary loads when applied close to the frangible region but to fail under the combined action of shear and normal stress when loads are applied to the rigid members remote the frangible region, whereby the frangible joints receiving forces transmitted thereto after impact by a moving body with the structure will fail partially or completely and in the event of partial failure, will transmit the remaining forces to at least a second frangible j