• Concrete topping or structural screed: concrete slab, suitably reinforced, cast over the extrados of the weight-reduction element with a structural function.
• Incidental load (Qk): loads acting of an element which may vary in time. Table 3.1.2 of Italian Ministerial Decree 14/01/08 indicates the relevant value which also includes dynamic effects, on the basis of the category of use of the environments.
• Permanent load (Gk): loads acting on an element which do not change in time. Permanent loads are loads that cannot be removed during the life of a building, such as screeds, floors, insulation, plants and systems, machines and the weight of the structural elements.
• Formworks: system of enclosures within which the fluid concrete is cast and left to set. The formworks are removed after the concrete has started to set, when the concrete has a mechanical resistance sufficient to guarantee the absorption of the stress for which the structure is designed; formworks may be made of wood, polystyrene, plastic and metal.
• Characteristic load combination: combination of loads acting on a structure (permanent incidental) with coefficients of amplification equal to 1, used to verify the structural elements; also called rare combination (fr = Gk+Qk).
• Ultimate load combination: combination of loads acting on a structure (permanent and incidental) with amplification coefficients that allow for variability in calculating the characteristic of the loads, used to verify the structural elements at the ultimate limit state. In general an amplification coefficient of 1.3 is used for permanent loads and 1.5 for incidental loads (fu = 1.3Gk+1.5Qk).
• Compression: elementary force or stress to which a body may be subject, characterised by the normal force at the transversal section of the element.
• Concrete consumption after striking: volume of concrete per m2 of floor used to fill the formworks to the top edge of the same.
• Pantile: a type of tile, usually brick.
• Stringcourse: element of construction on each floor along the edge of the slabs to separate the floor and the brickwork above and below. The stringcourse distributes the load of the brickwork above, but connects the walls, to stop them opening up under stress. The stringcourse is usually made of reinforced concrete with longitudinal steel rods and brackets.
• Bending: elementary stress to which a body can be subject due to the effect of its limits, as it reacts, resisting a system of forces applied to the same which tend to make it bend; the result is traction and compression on the element.
• Lean concrete: concrete made with a limited quantity of cement (less than 150 Kg/m3), and an aggregate grading curve with quite considerable dimensions. The lean concrete is used as a foundation bed to create a clean, horizontal layer for the foundations, and to distribute the load over a larger area, reducing ground tension. Another important function of the lean concrete is to keep the foundations off the ground, preventing contact with damp earth and the risks of corrosion in the reinforcement.
• Screed: horizontal element of construction used to level the surfaces where the floor will be installed; the thickness is variable according to the type of environment and pipes and cables can be laid in the same.
• Floating floor: a raised floor that isn’t fixed to the supporting structure and is installed at a certain height above the extrados of the floor, to obtain a floor with an airspace below (for distribution systems) to contain plants and systems.
• Pressure on ground: load in terms of force per unit of area (pressure) bearing on the ground as a result of the weight of the structure.
• Puncturing: typical breakage mechanism of plates, caused by a concentrated load (such as an external force on the system or a reaction of load-bearing points), which causes a breakage, shearing the plate around the load.
• Radon: carcinogenic radioactive gas, the main source of which is the ground. Radon is released from the ground to be dispersed in the environment. It can reach harmful concentrations in closed rooms.
• Shear: elementary stress to which a body may be subject, generating tangential tension in the element that tends to make the sections slide.
• Ventilated roof: covering constructed to obtain an upwards airflow from below the final covering; in summer cool air, from under the eaves, is warmed in the air space which has been heated by the sun, the hot air rises and escapes through the ridge, cooling the roof; in winter the air circulation keeps the insulating material dry, preventing condensation and guaranteeing the long life of the constructional elements of the roof. In the case of snow, the ventilated roof helps the snow melt in a uniform manner on the roof, preventing the formation of ice barriers.
• Ventilation space: air space in contact with the ground used in constructions to improve the conditions of the living environment.