In a reinforced concrete beam depth id 640mm.Depth of neutral axis is 0.43363d.Determine max compressive stress in concrete using hognested model when strain in steel reaches0.00284.Solve
In hognestad curve of stress strain we need ultimate stress value in concrete structure to calculate stresses in concrete. In the absence of the actual stress strain curve of the structure we can use simplified curve as given in the attachment. On the basis of data provided by you and assuming that I have understood your question correctly then the stress can be calculated as given in the attachment.