Shear transfer strength of uncracked interfaces: A simple analytical model

This paper presents a simple analytical model for the estimation of shear transfer strength (STS) of uncracked (UC) interfaces. Model is based on the combination of cohesion resistance offered by concrete and frictional resistance offered by the reinforcement provided across the interface. Coefficient of friction is derived from the experimental data of pushoff specimens with cracked interfaces. Analysis of one hundred forty eight push-off specimens with cracked interfaces collected from the literature showed that a relationship exists between coefficient of friction and the amount of clamping stress. The derived relationship of coefficient of friction was used to work out a relationship between cohesion and concrete compressive strength using the experimental results of twelve push-off specimens with UC interfaces tested in the present study. The proposed model was compared with the models for UC interfaces available in the literature as well as with the provisions of AASHTO LRFD-14 and CSA A23.3-14. Comparison was made on one hundred seventy five push-off specimens with UC interfaces collected from the literature. Results of the comparative analysis revealed that the proposed model produced uniform and precise results over the entire range of clamping stress.