ABSTRACT
However, if one were to go measure any of these parameters in the eld it would quickly become obvious that there is considerable variability in the observations. is is true of almost all engineering equations used in practice. is does not mean the equations are incorrect. Rather, it may be that the equation refers to average conditions, or it may indicate that the formulas are a useful approximation. e most famous example of this is Newton’s law that force equals the product of mass and acceleration. Einstein showed that, in general, this model is incorrect. Nonetheless, it is easy to argue that the model is extremely useful in bridge design.
