Extracted text: The following principle is taken from Abeles (Ref. 2.32) and applicable not only to prestressing concrete but to any endeavor that the engineer called upon to undertake: Explain this principlein relation to prestress concrete design. 2. You cannot have something for nothing. (One has to pay in one way or another for something which is offered as a "free gift" into the bargain, notwithstanding a solu- tion's being optimal for the problem.)