PRESTRESSED CONCRETE 16.1 INTRODUCTION Prestressed concrete structures can be defined as concrete structures where external compressive forces are applied to overcome tensile stresses caused by unavoidable loads due to gravity, wind, etc. In other words, it is precompressed concrete meaning that compressive stresses are introduced into areas where tensile stresses might develop under working load and this precompression is introduced even before the structure begins its working life. This chapter gives a brief introduction to the basic aspects of prestressed concrete design. For a more extensive treatment, the reader is referred to Bhatt (2011). One of the disadvantages of reinforced concrete is that tensile cracks due to bending occur even under working loads. This has four major disadvantages.  Cracks encourage corrosion of steel.  A cracked concrete beam is much more flexible than an uncracked beam. This

means that when using a reinforced concrete beam, one could have serviceability problems due to deflection or even due to cracking if too slender a beam is used.