| The helix shape is an aesthetically pleasing one that has rarely been used in structural design. This study contains a complete analysis on the use of the helix shape in the design of a steel bridge with a span length of 2000 feet. The 2000 foot span is longer than that of any other steel non-suspension or cable-stayed bridge in the world. The initial trials find the weaknesses in the helix shape, the first of which is the lack of support for the members as they circle about the deck, which causes excessive deflections. The other notable flaw is the excessive thinness of the design near the supports, making it extremely susceptible to shear. An alternative design solution that contains the aesthetic beauty of the helical curve along with satisfying the structural strength needs is found and recommended. The solution is to combine a "full-helix" shape with that of the "half-helix", which provides the necessary support and aesthetic qualities that were initially set but to be studied and optimized. The final design passes all necessary code standards that are tested for in the design program during the analysis. |
