The steel arches is a modular arched structure in which the efficiency of the shape is enhanced by the slim and clean of the truss. The steel finish obtained with galvanic galvanization guarantees long durability without high maintenance costs. Structures of this type are designed to satisfy the minimum dimensions required by the sports practiced indoors in compliance with the regulations in force in the place of installation. This type of structures are completely comparable to traditional buildings in every way, with the advantage of being safer against earthquakes, having better lighting performance and having a more advantageous price. The steel arches structures can be configured for different types of ends, for different roofing membranes with different thermal performances and different types of perimeter infills.