Issue 39

P. Konecny et alii, Frattura ed Integrità Strutturale, 39 (2017) 29-37; DOI: 10.3221/IGF-ESIS.39.04 30 of the progress of the degradation process caused by the long term actions of environmental and structural loading. (see e.g. [3-10]). However, models that aims to investigate durability of bridge deck with cracks or even waterproof membrane both from deterministic, not mentioning probabilistic, standpoint are still under intensive development. Moreover, information about the scatter or uncertainty of model parameters are of particular interest. For example, one of probabilistic 1d models of ideal bridge deck without cracks [4] applied description of variability of diffusion coefficient, surface chloride concentration, reinforcement depth in the form of frequency histogram. Histogram were based on measurements from real bridges in the Northwestern United States [11]. There are also other studies dealing with input parameters for chloride affected bridge deck steel reinforcement corrosion. The effect of steel protection reinforcement is presented in [12]. Surface chloride concentration and is part of the study dealing with epoxy-coating protection effect [13]. This study also provides data for the epoxy-coating defects. There are also attempts to codify the model and description of probability density function. fib Model Code [5] contains description of the 1d chloride ingress model with aging effect including recommendation for probability density functions of input parameters. Joint Committee for Structural Safety has prepared draft of the chapter 2.19 Environmental Attack . However, this chapter is not publicly available [14]. Since the concrete is brittle material where cracking occurrence is accepted thus crack effect on the chloride ion penetration shall be considered. There were attempts to reflect the need for the crack effect modeling. The Finite Element Analysis (FEA) of chloride ingress into concrete with crack was considered in [6] and [15]. Both models were based on the second Fick’s Law of Diffusion. The aggressive chloride exposure was applied as boundary conditions of a concentration of chlorides applied directly in nodes relevant to surface as well as to crack position. In contrast, the authors in [16] model the effect of cracks in the form of changes in the material parameters in the area of the crack. Moreover the crack width effect important for the chloride ion penetration into concrete is discussed in [17]. Presented work aims on the indicative evaluation of the effect of randomness of input parameters on two examples: directly exposed bridge decks and bridge decks protected by waterproof insulation (see Fig. 1) . The possibilities of innovative crack effect modeling, presented briefly also in [18], are discussed more in depth here in. The results of deterministic and probabilistic assessment of the selected bridge decks are compared. Reinforced concrete slab Reinforcement protected with an epoxide coating Asphalt overlay Waterproof membrane Reinforced concrete slab Unprotected reinforcement Figure 1 : The RC bridge deck scheme with epoxide protection of reinforcement typical for the North East part of the USA (left) and waterproof insulation typical for Central Europe (right). 2D FEA D IFFUSION M ODEL T AKING I NTO A CCOUNT THE E FFECTS OF C RACKS he FEA model [18] applied herein focusses on the transport of chloride ions through a RC bridge deck with a transverse crack and on an estimation of the concentration of chlorides at the reinforcement level or in places with damage to the epoxide coating of the reinforcement. Besides the capability of the modeling the cracking effect feature, the model also allows for simplified description of the damage to the waterproof insulation under the asphalt coating. The durability evaluation of selected bridge deck protection strategies is based on the work [4] and [6]. It is enriched by introducing the effects of the aging of concrete via time varied diffusion coefficients [19]. Model allows for chloride ingress modeling and corrosion initiation analysis. The available model is supplemented with a special description of the effect of cracks in the directly exposed bridge deck. The crack is applied in the form of introducing a highly permeable area [16-18]. The crack area is formed as narrow elements with width of crack. This approach allows for rather fast computation even though the irregularity of element T

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