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-'t!t.r&rFU9_.t'M',<~\ ~ ,."",^,t'; 'i~*~>~!f!('Ji{Jffnz~~!_~ l~tl:ik.~~ " ! ,,1I~J~t~. CITY OF SUNNY ISLES BEACH :~ilh. I- ,. . . . I. I. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~- ba Bermello Ajamil & Partners,lnc, 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 approximately 100'-0" measured perpendicular between the existing bulkheads. This canal width shall be maintained with the extension of the existing bulkhead, Due to the roadway alignment, the total bridge length will be approximately 170'- 0" measured along the centerline bridge, A Bridge Development Report (BDR) will be required to determine which bridge type and span arrangement is best suited for this location based on cost, aesthetics and constructability, Based on past experience, a cast-in-place concrete fiat slab or voided slab is the preferred superstructure altemative for this type of location, but would require intermediate supports in the water. These concrete slabs are ideal for low level bridges where shallow superstructures are required, This superstructure type is commonly used for canal crossings minimizing the impacts to existing adjacent roadways and properties while still maintaining vertical clearances over the canals, Also, a cast in place structure is well suited for this type of bridge due to its complex geometry, If a clear span over the canal is absolutely required, a variable depth cast-in-place girder or cable-stayed fiat slab bridge may be used. These bridges are the most aesthetically pleasing, but the most expensive as well, The following is a brief description for several options of varying complexity, aesthetics and cost to be further investigated in the BDR, 1, Short Span Flat Slab Bridge - The bridge would consist of cast-in-place slab construction with a typical span of 40', The superstructure slab would be constant thickness (12" to 18") and reinforced with a combination of mild reinforcing and post-tensioning, This type of superstructure would require four (4) continuous spans and three (3) intermediate supports in the water, The substructure type would be pile bents, consisting of driven precast, prestressed piles and a east- in-place bent cap, The orientation of the piles shall be parallel to the fiow of the canal to minimize the collection of any debris, Order-of-magnitude estimate would be $130/sf. 2. Medium Span Voided Slab Bridge - The bridge would consist of a cast-in-place voided slab with spans ranging from 80' to 100', The depth of the voided slab would be approximately 2'-6", The voided slab would be post-tensioned in both the longitudinal and transverse directions, This type of superstructure would require two (2) continuous spans and one (1) intermediate support in the water. The substructure could consist of two (2) drilled shafts at each pier location. The drilled shafts would have diameters between 4' to 6', This solution offers improved aesthetics over Option 1, The depth of structure may have a negative impact, Order-of-magnitude estimate would be $160/sf. 3, Clear Spanning Girder - The bridge would consist of a variable depth east- in-place box girder, The clear span would require back spans to minimize structure depth. The depth of the girder at the bulkheads would be such as to require demolition, excavation, and de-watering during construction, The substructure would consist of either drilled shafts or driven piles, supporting www.bermelloajamil.com 5