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:~. North Bay Road Pedestrian/Emergency Vehicle Bridge and Town Center Observation Deck & Boardwalk '...': ' " " Single Span has the following disadvantages: . . For this span length, a major increase in Construction Cost. · Increase difficulty in construction. · Increase Maintenance 2.] .2. Bridge Type Alternatives Alternate I: Three-Span Prestressed Concrete Beam Brid2:e This alternate consists of a three-span bridge with spans of approximately 43 ft. The three-span bridge structure consisting of prestressed concrete beams with a composite CIP deck. The most economical support for this span arrangement would be pile bents. In this case prestressed concrete piles are driven and tied at the top with a conventionally reinforced concrete cap forming a bent. To minimize impact to the vertical clearance at this crossing, AASHTO Type II girders are recommended. Exhihit 1 shows the proposed cross section for Alternate I. Our Preliminary Construction Cost Estimate for Alternative L a Three-Span Prestressed Concrete Beam Bridge, is shown on Tahle 5.1. . Alternate II: Two-Span c.I.P. Post-Tensioned Flat Slab Brid2:e The alternate consists of a two-span flat slab bridge. This option would minimize the impact to the environment by requiring only om~-water pier. As mentioned above, the most economical type of substructure would be a prestressed concrete piles bent. The proposed cast-in-place flat slab deck would consist of an average 24" post-tensioned slab. The slab would be designed to take on all construction and dead loads. The Post-Tensioning would be introduced to handle live load. A cast-in-place structure would offer the additional opportunity to introduce aesthetic lines to the crossing. Er:hihit 1 presents the typical cross section for Alternate I I. Our Preliminary Construction Cost Estimate for Alternative II. a Post Tensioned Flat Slab, is shown on Tahle 5,2. Alternate III: Sin2:le Span Cable-Stav / Flat Slab Brid2:e Given the span length of this crossing and the low profile constraint, our recommended bridge structure alternative for the single span structure consists of a cable-stayed bridge with a single tapered pylon. The bridge deck would be a symmetrical post-tensioned concrete flat slab constructed on false work (similar to that proposed for Alternate II). The flat slab deck would consist of an average 24" slab post-tensioned. The slab would be designed to take on all construction and dead loads. The post-tensioning would be introduced to handle pedestrian live load and the stay cables would be designed to take the vehicular live load. . This alternate minimizes the depth of the structure to comply with given constraints. However, this typc of structure is a costly alternative for this location; a cost which may not be justified at this site. Request for Qualifications No. 07-03-01 Page 6 of 15