This structural system, which emerged almost a century ago in the United States,
as an evolution of the wooden framework,
has more and more implantation in Spain,
due to its versatility, economy and speed of execution.
Structures composed of rolled steel profiles forming frames and trusses,
both two-dimensional and three-dimensional,
are often the most efficient solution in singular buildings
with structural situations of certain complexity.
The structural system of frames, floors and reinforced concrete slabs
is still the most widely used today,
especially in conventional buildings with small or medium spans.
Its main values are economy,
stiffness of the joints and good acoustic behavior, as it is a heavy system.