The dimensions of the stringers have a substantial effect on the behavior of the physical model. In
addition, the stringers distribute the applied load to the piles and into the soil. Because the steel
load frame supports the abutments and the interior bents are supported by a significantly less stiff
soil, the stiffness of the stringers will have an effect on the load distribution into the abutments
and bents. If the stringers are too stiff, the bridge will behave more like a single-span bridge with
soft springs where the bents are rather than a three-span bridge. If the stringers were too flexible,
their deflections for the estimated loading would too large and would deflect as if the pile cap
supports were rigid and therefore measurable support motions would not be produced.