Title : LIFE ASSESSMENTS OF CONCRETE STRUCTURES ACCORDING TO ISO 16204: 2012
Authors : Steinar Helland SKANSKA Oslo, Norway AS, Email: steinar.helland@skanska.no
Publication : December 19-21, 2013
Volume :
Pages : 152-166
Price : 250
Abstract : All parameters governing the length of a concrete structure’s service life have a statistical spread. These include the micro-climatic environmental load (like CO2 and chloride concentration) and the structure’s resistance (concrete quality, cover to the reinforcement). Obviously also the service life will vary in a statistical way throughout the structure. All assessments of the service life of a new structure, or the assessment of an existing one, must therefore be done in a probabilistic environment. fib (the international federation for structural concrete) published a “Model Code for service life design” in 2006 giving the methodology for such assessments. This methodology is later implemented in fib’s full Model Code 2010 and was last year (2012) also accepted as the ISO 16204 "Durability - Service life design of concrete structures". This ISO standard is the reference for the provisions on service life design (SLD) in the revised European standard, EN 206 presently for formal vote. This paper will give an overview of the methodology given in ISO 16204. All these documents foresee that practical SLD of new structures will also in the future normally be undertaken by so-called “deemed-to-satisfy” requirements (tabulated sets of cement type, w/c, cover thickness, etc). However, these requirements should be calibrated by the responsible standardization committee according to the principles laid down in ISO 16204. For the assessment of the remaining service life of existing structures, also the full probabilistic approach will be viable as the input parameters to the calculations might be derived directly from the structure. ISO 16204 opens for national choices given in a national annex.