ABSTRACT
It is worth noting, for the sake of humility, that the basic ideas of composite behavior were conceived and attempts at composite construction made long before anyone reading this work was born. In the United States, composite construction first appeared in 1894. In that year, Joseph Milan, an engineer from Vienna, built a composite bridge in Rock Rapids, IA, using steel I-beams bent into an arch shape, and then encasing concrete around them; he claimed that steel and concrete acted together. So confident was he of this system that he applied for and eventually got an American patent by submitting deflection calculations to prove his theory. Replacement of the curved beams with straight beams was the next step. By the turn of the century, steel beam encasement in concrete was a regular practice in both buildings and bridges. However, it took some 30 more years to codify the composite design. The design rules first appeared in the 1930 New York City Building Code when fully encased steel beams were permitted a bending stress of 20 ksi, an 11% increase over the 18 ksi allowed for noncomposite beams at that time.
