September 16, 1968
A design of any engineering structure may be said to be optimum when it can meet all the necessary requirements at a minimum possible cost. In all cases there is a probability, however slight (sometimes even incalculable because of lack of data), that the design load can be exceeded and, thus, damages could occur. Obviously, lower the design load, higher would be the cost of anticipated damages and vice versa. Thus, from economical standpoint alone, the ideal solution would be when the total cost of construction and anticipated damages is at its minimum. Very often, however, other factors like social political, etc., have to be considered, and this makes the whole process a complex decision-making problem—sometimes completely out of the jurisdiction of the engineers.