Abstract
The use of the ordinary straight line theory for calculating the flexural rigidity of reinforced concrete beams has not met with success, essentially because beam deflection is affected by plastic deformations in the compression zone of the concrete and also by the co-operation of the concrete between cracks with the tensile reinforcement. Under the consideration of these effects, it was attempted in this investigations to formulate the principles of the theory for calculating the opening up of cracks and the flexural rigidity in reinforced concrete bending members. In developing the theory the concept of the mean deformation of tensile reinforcement in concrete along the sections between cracks was introduced. This concept was comfirmed by the results of our past experiments on axially reinforced concrete prisms subjected to tension. Furthermore, the formulae developed in this study was verified by means of experiments on simply supported reinforced concrete beams having the various distributions of tensile reinforcements.
