Assessment of crack width estimation models for RC tension members

The objective of this study is to assess the crack width estimation equation suggested in CEB-FIP Model Code 1990 (1991) in terms of concrete strength. To evaluate the crack width estimation equation, a numerical model for a crack element is introduced by adopting detailed bond stress slip models. A remarkable advantage of the use of the model is that all significant internal variables within a crack element can be analysed, including average bond stress and tension stiffening effect, which are the vital parameters for the equation in CEB-FIP Model Code. Experimental results from literature were compared with those obtained by the estimation model equation in CEB-FIP Model Code and by the numerical analysis using the crack element model. The average bond stress and tension stiffening effect given in CEB-FIP Model seem to be overestimated and thus need to be reduced to properly reflect the effect of concrete strength.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0024960)