Spacing of Cracks in Reinforced Concrete Based on a Variable Transfer Length Model

A method is proposed to indirectly determine values of the transfer length in cracked RC based on the observed load-deformation responses of RC tension members and their crack configurations under increasing load. The transfer length is characterized on the basis of results of several tension stiffening studies in the literature, including recent tests by the authors. In the present study, the transfer length is revealed to be strongly load-dependent, accounting for the gradual deterioration of the tension stiffening effect with increasing load. A solution is identified for the classical problem governing the relationship between the average crack spacing and the transfer length, and it is demonstrated to yield accurate estimates of average crack spacing for a wide range of RC tension and flexural members. Based on empirical crack spacing distributions of real RC members, a statistical approach is adopted to characterize the minimum and maximum spacing of cracks. (c) 2018 American Society of Civil Engineers.