Choice of Main Bonded Reinforcement

All main bonded reinforcement shown on vessel drawings cannot be less than 1 (31 mm) high tensile GK + 60 bar. Minimum requirement of 

1 Choice of the Minimum Percentage of Main Bonded Reinforcement 

In Hunterston B , a desirable assumption is made that the bonded reinforcement is capable of maintaining a strain of 100 micro-strain throughout the vessel in order to assist in the formation of a well-disposed crack pattern, hence a strain of 100 X 10 can be propagated if the percentage reinforcement is of the order 250 

Bonded reinforcement is considered up until now to control tensile stresses in the concrete of the vessel. In fact, concrete is subjected to both tensile and flexure effects. The flexural stresses arise from the temperature cross fall through the vessel barrel. As a pure flexural member (refer to Fig. 8.1), the estimate is that only one-half of steel areas mentioned above would be necessary. Since the conditions in the vessel are partly between these two cases, it is justifiable to take 0.2% bonded steel, made up of 0.15 and 0.05% on the outer and inner faces, respectively, as discussed earlier. 

In actual vessel tensile stresses up to 500 or 600 psi (3.45-9.14 MN/m ) will exist at the outer face of vessel concrete during working conditions for 15°C temperature cross fall. 

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