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--- , At """'~ ,'/" ~fP>.;" , ~ '::'- \, ~)'I>- , fit CITY OF SUNNY ISLES BEACH I- . . . . . . . . I. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ba . ~- Bermello Ajamil & Partners, Inc, Professional General Engineering Consultant for the North Bay Road Pedestrian and EmergencyVehicle Bridge, and the Town Center Park Observation Deck and Boardwalk Miami-Dade County concrete footings. This solution provides an improved aesthetic from the previous two options, Constructability issues related to the depth of the bridge would be problematic, The depth of structure may have a negative impact, Order-of-magnitude estimate would be $200/sf. 4. Cable-Stayed Flat Slab Bridge - Though a more exotic looking solution, the cable stayed option permits longer spans while keeping a thin superstructure, Pylons would be constructed in appropriate locations to provide support to the curving superstructure, The bridge shall be a three span structure with the center span clearing the channel and the anchor spans behind the abutments, Order-of-magnitude estimate would be $240/sf. Other superstructure types include prestressed concrete beams and steel girders, Although it may be possible to span the canal with this type of superstructure, the superstructure depth required will be approximately 8'-0" or more which make this an impractical solution and would require intermediate supports in the water. These superstructures types are not recommended and are briefly discussed below, 1, AASHTO Type Beams - Prestressed beams are the most common type of superstructure used throughout Florida due to their economy, ease of erection, low maintenance and acceptable aesthetics. AASHTO Type beams are an ideal choice for span lengths between 60 to 140 feet, but the complex bridge geometry would result in large overhangs and complicated framing. The approximate bridge length of 170'-0" exceeds the practical limit of AASHTO Type beams and would require intermediate supports in the water, An AASHTO Type II beam with a girder depth of 3'-0" is ideal choice for simply supported span lengths of 60'-0", but the superstructure depth including an 8" reinforced concrete deck would produce a significantly deeper structure than a flat slab, Due to these reasons, AASHTO Type beams have been eliminated from further consideration, 2, Structural Steel Beams - Steel beams are a popular choice for curved bridges, but is not recommended due to its close proximity to the water elevation, The FOOT prefers avoiding the use of any steel structural bridge elements within 25 feet of the water elevation for maintenance reasons, especially in aggressive environments due to chloride content, Furthermore, in order to span the canal with steel beams, a superstructure depth of approximately 8'-0" is required, Intermediate supports may be provided to reduce the beam depth, but the total superstructure depth including an 8" reinforced concrete deck would still be significantly more than a flat slab, For these reasons, structural steel beams have been eliminated from further consideration, The following are the preliminary construction costs based on a bridge width of 43'- 0" and length of 170'-0", The bridge length used for the clear spanning girder and cable-stayed flat slab includes the back spans, The costs were increased by 6% for urban construction in Miami-Dade County and by 3% for construction over water. www.bermelloajamil.com 6