Design for service life: implementation of fib Model Code 2010 rules in the operational code ISO 16204

Abstract

CEB/FIP Model Code 1990 (MC-1990 [1] Structures 2010 (MC-2010 [5,6,7] BackgroundDurability of concrete structures, and in particular the lack of such, has been in the focus of society in general over the last few decades. Excessive repair needs have challenged our industry. The traditional approach in most national and regional concrete standards is to specify the provisions to ensure a certain design service life by limiting values for material composition and geometry based on the expert opinion of the code committee.There are several weaknesses in this approach: -It is often unclear as to which condition represents the end of the service life.-The required level of reliability for the design is often unclear as well. -The criteria should be based on long-term field experience. Such experience is, however, not normally available for modern materials and design concepts, and concepts with service records > 50 years are seldom in use any more.In 1998 a group of 19 European enthusiasts, all of us with a long record within CEB and FIP, signed a contract with the European Commission to develop a platform for durability design of concrete structures that contained the same elements and philosophy as that of modern structural design. This European network was named "Duranet", and the contract lasted until 2001. At DuraNet's final workshop in Tromsø, Norway, in 2001, attendees from Europe and North America worked out a plan for how to progress to get this methodology standardized and implemented in the industry worldwide (Fig. 1). The obvious environment for this was ISO.Some of us therefore met at the ISO TC-71 meeting in Norway that autumn and presented our visions. TC-71, responsible for concrete-related standardization within ISO, endorsed the initiative, but quite correctly made us aware of the fact that ISO normally starts its work on the basis of existing documents. We therefore agreed to ask the International Federation for Structural Concrete, fib (formed by the merger of CEB and FIP) to work out such a model for a standard. , which came up with a roadmap for how to implement limit state and reliability-based service life design in standards.

Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

“…Both the origin and the values of this crack width limit are questionable, as was so well stated by Helland [56]: "Intuitively we assume that cracked structures will deteriorate faster than uncracked structures. However, neither the fib nor the ISO committee was able to come up with any general model to take this effect into account."…”

Probabilistic degradation modelling of circular tunnels assembled from segmental linings

“…In order to be able to apply the probabilistic approaches to the service life of a tunnel, we need models describing these deterioration processes over time. But at present, no time‐dependent models for these cases with general international consensus are available, as is concluded by the fib Model Code for Concrete Structures 2010 and ISO 16204 . Consequently, these deterioration processes are not taken into account in this research.…”

“…Experiments conducted by Cabrera [15] and Ballim/Reid [16] concluded that the corrosion percentage C perc and the deflection ratio D r are linearly related. The linear regression function for a Portland cement concrete beam given by Cabrera is adopted in this study: [29]. Consequently, these deterioration processes are not taken into account in this research.…”

Smart Crack Control in Concrete through Use of Phase Change Materials (PCMs): A Review

“…Since steel corrosion is an expansive reaction, it will then lead to cracking and spalling of the concrete cover [ 4 , 5 ]. As a consequence, service life design guidelines require that the concrete cover to the reinforcement is of a certain dimension and quality [ 6 , 7 ]. These guidelines are, however, derived assuming that the concrete cover is uncracked.…”