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I be required to retain fill material if the profile is raised. The height if these elements would be kept to a minimum, and the same architectural treatments used on the bridge would be carried through the walls to ensure a seamless structure. I Altemative 2: Tied Arch - The lack of available superstructure depth and emphasis bcing placed on aesthetic considcrations lend themsclves to a structure that is supported from above. The geometry of the site in combination with proposed roadway alignments make it difficult to implement a stay and tower system, but support the use of an arch and suspender configuration. A tied arch is a structural element that would allow the efficient usc of all structural components while providing a visually appcaling form. Thc structure would be slightly over built in width to permit the use of two parallel arches, allowing the roadway to meander across the deck as needed to meet the desired alignment. The deck would "tie" the ends of the arches together, resisting the forces developed and eliminating the need for massive thrust blocks. Intermediate points of support would be provided by a suspender-floorbeam arrangement, and a much shallower deck system could be employed since the main supporting elements would be above the roadway. I I~~ r~."" ~ I I I I I The arch could be constructed from stcel or concrete, and the deck would most likely be reinforced concrete integral with the floorbeams. Special attention would be paid to the aspcct ratio of the arch to avoiding overpowering the site and assure forces are efficiently transferred into the deck. In addition to meeting the vcrticalload demands, the two arch system provides superior lateral resistance to extreme wind loads, as expected during storm events. This is an important feature based on the location 0 f the proposed structure. I I There are several benefits associated with this alternative. In addition to behavioral gains, a tied arch structure would bc visually appealing. Propcr illumination and balanced color combinations could make this a truly signature bridge for the City. The added space resulting from the overbuild could be uscd as sitting and viewing areas even after the bridge is opcn to traftic, providing the plaza feel the City desires. Construction impacts on the community could be reduced through this design. The entire superstructure could be built off site and floated into place via barge. This would eliminate the need for shoring in the waterway and would expedite construction due to improved accessibility. I I Altemative 3: Single-Rib Arch - A single-rib arch is another way of efficiently supporting thc deck from above. Over building would not be required for this option, for the arch would span the suspended deck at a diagonal, and would not be connected to the deck as with the tied arch option. Again, the arch could be of concrete or steel, and the dcck would be reinforced concrete. Reinforced concrete thrust blocks would be required to resist the arch forces, and stub abutments supported by drilled shafts would support the deck. I I I ';J' 2" Altemative 4: Two Span Florida V-beam - The geometry of the alignment and the span length of the crossing lend themselves to a two-span alternative. Many benefits could be gained by placing a pier in the center of the waterway, both from a design and a construction standpoint. Doing so would permit the use of a chorded framing system using straight supporting elements and accommodating the curved Florida U-beams (FUB's) would be used for this alternative. I I I ~- , ~-'l O:r~' _.' "lO;;U. '_'3EtI'.. :TYF.' I deck by varying the overhang along the fascia girdcrs. I I