State-of-the-Art Report on Ultimate Strength of I-Beam Bridge Systems

The load factor design criteria in the 1973 AASHO Specifications represent a step forward, but only a first step in what can be a progression of more advanced design concepts involving: (1) The definition of the resistance and load factors by implicit use of first-order probability theory; (2) the explicit use of probability theory; and (3) optimization of benefits and risks on all levels of performance. The implementation of the first of these steps is now possible with available data on resistance and on loads. Work toward this goal is being performed on steel buildings and tentative criteria for these are now available. The implementation on a sufficient scale of the more advanced steps is still in the future, demanding more refined statistical data and the reduction of complicated analytical methods into practical tools.