Crack width for thick offshore plates

Abstract

Using thick concrete covers in offshore and nuclear containment applications is increasing because it is a durability issue. Most crack width models indicate that increasing concrete covers results in increased crack spacing and hence increased crack width this means that thick concrete covers are detrimental to crack control. In this paper, tests were conducted on two groups of thick plates. Group I, included five specimens that had two concrete covers, 60 and 70 mm. Group II, included four thick heavy reinforced specimens; all specimens in this group had a clear concrete cover of 70 mm. Using thick concrete covers is a common practice in offshore and containment structures for nuclear power generation. The objective of testing both groups is to measure flexural crack widths under different load levels and, most importantly, under service loads. Group I was intended primarily to investigate the effect of increasing the cover and bar spacing on the crack width. Group II represents a unique experimental investigation in assessing the magnitude of crack width in full-scale thick plates under service loads. An analytical investigation is presented in this work. The main focus of this study is to evaluate the available codes’ models for estimating the crack width of thick concrete plates having thick concrete covers used for offshore and nuclear containment structure applications. It was concluded that crack control can still be achieved by limiting the spacing of the reinforcing steel despite using thick concrete covers.