Assumption in theory of simple bending of RCC structure(working stress method) 1. A section which is plane before bending remains plane after bending. 2. The concrete and steel reinforcement are perfectly bonded . 3. All tensile stress are taken up by steel and non by concrete. 4.the stress strain relation of Steel and concrete under working load is a straight line. 5. The modulli of elasticty of Steel and concrete are constant. 6. The modular ratio has the value ,where. Is the permissible compressive strength of concrete ...