Ficha de características técnicas de un forjado nervado de hormigón armado

Document of technical characteristics of a reinforced concrete ribbed floor

Floors are plain resisten members of buildings' storeis and roofs. They are executed nowadays normally in Spain industrialized floors with joists or precast panels made of reinforced or prestressed concrete, complemented with reinforced steel and in site concrete. They require an Authorization of Use from the Ministry of Fomento, who draws it up in a Document of Technical Characteristics, which is brought by the fabricant, and constitutes an efficient database for the design and execution of industrialized floors. Ribbed floors, made of reinforced concrete without resistent precast members are also used, but there is no fabricant whom to ask for the Document of Technical Characteristics, it's values having to be reckoned in the architect's office. A tabulation of the technical characteristics of an usual system for a ribbed floor is given in this paper, which has been given calculated in order to help architects who have to dimensionate them in the conditions of ultimate and serviceability limit states. The methods used to calculate them are exposed in an example, hoping it may be useful to those who have to design floors, being good for strengthening the concepts and algebraic formulae used to determine the technical characteristics. Functional characteristics of this ribbed floor, such as termic, fire resisting and acoustic, are not required for the Authorization of Use, but are needed for more and more everyday. For that reason, have also been included and they are presented in a second tabulation. For helping in the use of tabulations, the floors of a storey of a residential building have been calculated, detailing the stages followed for the conditions of the limited states. The notation employed and bibliography are included too.