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D-26 RFQ 20-10-01 Professional Engineering and Architectural Services for Pedestrian Bridge with Park Elements Across A1A at 174th St. CCNA D To minimize impact to local traffic, precast decks can be used, integrating with the U-beams, for an integral bridge structure. The bridge layout and pier structures will have the architectural and park features desired by the City. Foundation systems like Auger Cast- In-Place (ACIP) piles, driven piles, and drilled shafts can be considered. Driven piles will create vibration and noise and have impact to the existing structures and local activities. ACIP piles and drilled shafts will eliminate these concerns. Drilled shafts also have the least footprint, which may be critical to minimize impact to local traffic during construction. In the preliminary design phase, we will evaluate different structural systems for both the superstructure and substructure, along with the park themes and architectural features in close coordination with the City. Final design will be performed per the City’s selected alternative. The bridge’s typical section will include both landscaping and pedestrian zones separated by glass railings. The minimum width that we recommend for the pedestrian walkway zones are 12-feet., but with additional space to add landscaping and seating and other amenities. We propose the landscaping be provided separate from the bridge structure for maintenance concerns. The elevated bridge park will include benches, planters, steps and ramps, bicycle racks, trash and recycling receptacles, railings, and aesthetic lighting. GEOTECHNICAL/FOUNDATIONS The EAC Team has reviewed all data available to determine the geotechnical approach for this project. The presence of the variable subsurface conditions - coupled with a residential setting, high traffic volume, and a noise sensitive site –- makes the foundation design and construction extremely challenging. Our approach will make full use of our knowledge as the lessons-learned from recent construction projects. All required geotechnical services will be performed in accordance with FDOT’s current Soils and Foundation Handbook (2020). Borings and rock coring will be required at each foundation location to confirm the subsurface conditions in the project area. One SPT boring per pier/bent will be performed to obtain more comprehensive geotechnical information and to reduce risks of pile or drilled shaft overruns and schedule delay. The EAC Team has performed a preliminary evaluation of shallow and deep foundation options. Given the unfavorable near-surface subsurface conditions, spread footings are not feasible - due to the relatively low soil bearing capacity and predicted excessive settlements from the underlying loose to very loose sandy soils. Drilled shafts are a feasible foundation system - using relatively low vibration equipment - and hence are friendly to the surrounding environment. Since FDOT has now allowed the use of ACIP pile foundations for bridge structures, we will also explore the use of 24-in. diameter ACIP pile foundations. Use of ACIP piles, similar to drilled shafts, will eliminate the risks of causing vibration-related damages to existing structures. FDOT has presently prepared developmental specifications for the use of ACIP pile foundations for bridge projects. GEOSOL is currently working as part of the FDOT Review Team for the I-395 design-build project, and working with FDOT’s Central Office in the implementation of ACIP piles for foundation of the signature bridge and the concrete box segmental bridges. For the elevators and stairs, the EAC Team will evaluate the use of ACIP. ACIP piles have been successfully and economically used on numerous transportation infrastructure projects in Miami-Dade County - including the City of Miami Beach’s West Avenue vehicular bridge over the Collins Canal, Miami-Dade Transit elevated guideway bridges, Miami International Airport (MIA) parking garages, MIA transportation hub, MIA vehicular bridges, and a 200-ft. high air traffic control tower at the Miami Opa-Locka Executive Airport. Also, in South Florida’s private sector, Auger Cast Piles are commonly used to support heavily loaded structures - such as high-rise condominium towers, hotels, and arenas. CONSTRUCTABILITY We have performed a preliminary constructability analysis for the bridge construction - focusing on the safety of structures and people - and with minimal impact to the traffic and local activities in the area. Use of precast elements will minimize the need for forms and falsework, facilitate the construction activities, and improve efficiency and overall progress of the construction. We propose to utilize precast concrete U-beams for the superstructure girders. The U-beams will be transported to the job site, first through water on a barge, then to the proposed bridge location by trucks, as shown in this proposal’s Beam Delivery Section. Two sets of cranes will be used to pick up the beams - one set at the docking area to pick up the beams from the barge and load them onto the trucks, and one set at the bridge location to unload the beams from the trucks and erect them in their designed positions related to the bridge’s structure. Maneuvering and operation of the cranes will be limited locally to the docking area and bridge location without any significant impact to the roadway and facilities. During the pick-up, transport, and erection of the beams, the local roadway will be closed at nights when traffic impact is minimal. Ensuring beams are properly installed at night, when the road is closed to traffic, and opening the roadway to traffic in the morning will minimize risks and efficiently facilitate the process.