Joint system for structural floor joints in seismic areas, up to 300 mm in width, subject to movements up to +/- 30 mm in commercial and industrial environments, also subject to heavy forklift and pallet truck traffic. The system, with a rectangular section, without side sub-flooring flaps and visible screws, is made up of a rigid central carriage in visible non-slip knurled aluminum and side seal in rubber with high resistance to vertical loads. The particularly low height allows it to be placed on the same laying surface as the adjacent flooring.