State the use of reinforced concrete
The use of reinforced concrete may not solve all the problems. For example, a very long reinforced concrete member, which may be subjected to heavy loads also, is to be provided with a big section. This makes it bulky and its increased self load further increases the external load effects. A greater amount of reinforcement may be needed in such a situation (making the member uneconomical) and even after its provision, tensile stresses in concrete may not be controlled to be lower than its tensile strength. In such situations, use of prestressed concrete may be of help.