Structural steel refers to the type of steel used as a construction material in civil engineering. Steel used in construction is an alloy consisting of approximately 98% iron, the remainder being carbon, magnesium and silicon. The most important characteristics are fracture strength, ductility, impact resistance and weldability, all of which influence the specific field of application. An important variable is the amount of carbon, the lower its rate, the lower the mechanical strength and brittleness while the ductility and weldability of iron increase. A steel structure is the result of theassembly of one- or two-dimensionalparts, most of which are produced in a different place from where the structure is manufactured. The correct functioning of a construction is therefore linked to the correct assembly of the various elements, which are suitably dimensioned. In steel constructions the individual elements are generally standard products manufactured in series and only a careful design of the connections and a correct arrangement of the structural components can ensure a coherent and optimal structural behaviour.

Fibre-reinforced concrete refers to composite materials obtained by adding fibres of various kinds to concrete. The fibres added may be metallic, natural or synthetic, and depending on their characteristics, composites with specific properties are obtained. The fibres can increase the ductility and fatigue strength of the concrete mix, improve its impact and abrasion resistance, reduce micro-cracking and the effects of shrinkage and increase its fire resistance.

Reinforced concrete was born in the second half of the last century, with the discovery of the setting and hardening properties of suitably calcined clayey limestone. It was the research and scientific knowledge on binders, followed by the industrial production of cement, that allowed the development of reinforced concrete as a construction system. Commonly referred to as reinforced concrete, it is a material used for the construction of civil works, a mixture of cement, water, sand and aggregates, stone elements, such as gravel with steel bars (reinforcement) embedded in it and suitably shaped, interconnected. It is a material used both for building structures and for artefacts such as retaining walls for embankments. Reinforced concrete exploits the union of concrete, which is resistant to compression but has little resistance to attraction, with steel, used in bars, embedded in the concrete in areas where it is necessary to cope with tensile stresses.

The term Fibre Reinforced Polymers (FRP) refers to a wide range of composite materials consisting of an organic polymer matrix with which a continuous fibre reinforcement with high mechanical properties is impregnated. Recently developed and marketed are composite materials obtained from an inorganic matrix, consisting of a hydraulic pozzolanic binder, and fibre networks, usually carbon. Like all composite materials, FRPs have an anisotropic and heterogeneous behaviour, but they guarantee a linear elastic behaviour until collapse. These materials have several peculiarities, which vary according to the type of FRP and which determine their field of application. The fibres have a high tensile strength and are therefore the resistant elements of the FRP material.

The use of wood as a building material is as old as mankind, older than stone and brick; in Italy, with the advent of reinforced concrete in the first decades of the 20th century and particularly in the post-war period, wood was somewhat forgotten, being replaced by materials that were certainly considered to be more resistant and durable. In reality, when the design and construction have been well done, numerous works demonstrate that wood has centuries of resistance. Only in recent years in Italy have we seen an important return to the use of this material, especially in the recovery of old buildings and in new constructions, but always and only for horizontal structures and frames. The products and construction elements derived from wood used in building works can be of various types but they all derive from the processing of the trunk of spruce, pine, larch or chestnut trees, which are the most widely used tree species for structural purposes in Italian arboriculture.