Expansion Joint system for joints up to 600 mm subject to high movements up to + / -100 mm, suitable for areas susceptible to significant overcrowding. The system consists of a central box made of galvanized sheet, to be filled with reinforced concrete (thickness min. 40 mm) and flooring, adjunct to the double expansion joint system, devoid of underfloor brackets. For H = 60 max G = 300. For H ≥ 80, 200