A tensile axial force in a cable, for example, of asuspension bridge.As one would expect, compression members have a large cross-sectional area withrespect to their length. This geometry is required to resist loads and avoid buckling of themember. Beyond buckling, there is also the concern of crushing of an axially loadedmember in compression. Members more susceptible to tensile axial forces, have across-sectional area which is small when compared to its length.So far, I have discovered that bridge loads are transmitted from the deck to thesuperstructure and then to the supporting substructure elements. Exactly how are theseloads transmitted through? If a truck is traveling over the top of a primary member, it islogical to say that this particular beam is resisting the truck load. This stringer, however,is connected to adjacent primary members through some form of secondary member. Inaddition to this, the bridge deck itself acts as a connection between longitudinal girders. This connectivity allows different members to work together in resisting loads. Returning to the example of the truck traveling over the top of a specific primarymember, it would be logical to assume that this specific beam is carrying most of the load. As a result of being connected with the girder is question, adjacent members assist in carrypart of the load. Exactly how much load they carry is a function of how the load istransmitted or distributed to them. Determining the fraction of load carried by a loadedmember and the remainder distributed to other members is what I will discuss now.The highway bridge, as mentioned previously, is not a collection of elements, eachperforming a specific function, but rather an integrated unit. The modeling of how a loadis actually dispersed from the deck down through the substructure is not a trivialundertaking. A wide variety of parameters which range from the structure's geometry toelement material properties inf...
