Baker's Haulover Cut Bridge Rehabilitation
Baker's Haulover Cut Bridge Rehabilitation
The Baker's Haulover Cut bridge is set to live its (next) best life.
Originally constructed in 1948 and previously rehabilitated in 1992 and 2000, it underwent another rehabilitation recently, with a goal of minimizing future maintenance, project cost, and impacts on a highly used roadway linking Miami Beach and the affluent Bal Harbour neighborhood to northern Miami-Dade County over Haulover Cut. The waterway provides access to and from the Atlantic Ocean from the Atlantic Intracoastal Waterway and sits at a location favored by recreational boaters.
The 13-span, 1,255-ft-long bridge, which consists of nine haunched steel riveted girder floor beam main spans and four steel multi-beam approach spans, carries four lanes of traffic, two in each direction. Rehabilitation work included steel repairs and selected member replacement, main span bearing replacement, selected replacement of approach span bearings, concrete repairs, seawall replacement, and painting of all structural steel.
The project came with several challenges from multiple directions. For starters, the road that the bridge carries, SR-A1A/Collins Avenue, is the only north-south thoroughfare running up the barrier islands that are separated from the mainland by the Atlantic Intracoastal Waterway. Any detour of the heavy vehicular, bicycle, and pedestrian traffic would have significant impacts on the overall congested traffic network of Miami-Dade County. Secondly, Baker’s Haulover Cut is a major outlet from the protected waters of the Atlantic Intracoastal Waterway to the Atlantic Ocean. It is the primary route for sport fishing and pleasure craft from dockage to the ocean in the northern half of Miami-Dade County, and reduction of vertical clearance in the main channel between bridge fenders was not allowed by the U.S. Coast Guard. Also, water currents through the cut are significant during the majority of the day, making in-water work difficult in all but short periods of slack tide each day.
In addition, the bridge carries infrastructure for eight different utilities, including electric transmission and distribution lines, a water main, cable television, and gas. The electric transmission line, in particular, was vital to the service provided to the affluent Bal Harbour neighborhood on the south side of the bridge, as the electrical network could not put that line out of service and still provide power to the residents, hotels, and other businesses in the area. Therefore, jacking the bridge to replace the bearings and repairing and painting the bridge near these elements would be tricky. Finally, seawall replacement within the Florida DOT (FDOT) right-of-way had been completed adjacent to existing seawalls at both shorelines. At the south shore, a beach and access road for the neighboring hotel needed to be maintained directly adjacent to the seawall, and any settlement of that roadway could not be tolerated. And at the north shore, an electric power facility just north of the seawall extended into the FDOT right-of-way such that care needed to be taken to ensure no damage to that facility. At both shorelines, any repairs for the portions of the walls under the bridge needed to be able to be performed with limited available headroom.
As a project funded with bridge maintenance dollars, it was important that the work be done within the construction funds budgeted by the FDOT. In order to tailor the design scope to the available funding and be as cost-effective as possible, a thorough inspection of the bridge was completed to ascertain conditions and take field measurements, and a full list of needed work was prepared, in order of importance, to address deterioration that reduced the safety and capacity of the bridge, and then work items were pulled from that list to fit the project budget.
In order to determine the deteriorated areas that needed repair on the steel members to improve capacity and to determine the need to maintain the threespan continuous girder-floor-beam-stringer spans bottom flange bracing, which had widespread losses, a complex finite element analysis (FEA) model was prepared in order to analyze these spans. Structural repairs included adding bottom flange cover plates to the floor beams to provide necessary increases in member capacity and girder web repairs at selected gusset plate locations where holes and section loss were present. The analysis results allowed the design team to effectively identify discrete areas that required repair and determine that the bracing was not required. In consultation with FDOT, it was decided that only bracing members with significant section loss and that had the potential to fall from the bridge would be removed. This decision removed more than $1 million from the construction budget, and the remaining bracing was left in place, cleaned, and painted.
Replacing the girder bearings on the three-span continuous steel spans posed its own set of challenges. The existing piers were not much larger than the masonry plates the bearings sat on, so there was no straightforward way to install temporary jacking assemblies under the girder flanges. Jacking the bridge from the floor beams was not possible due to load capacity issues and conflicts with the utilities mounted on the bridge, and a conventional system of jacking towers would have been very difficult to construct in the fast-moving waters of the Haulover Cut. As a result, the contractor proposed jacking the span at each pier using a very stiff saddle that rested on the pier cap between the girders and extended out from the caps and under the girder lines. An equal-displacement jacking system was used toensure even jacking of the span to avoid racking that could cause deck damage. The FEA model allowed the team to accurately estimate the jacking loads and determine the potential stresses in the top of the deck when a single bearing line was jacked. It also confirmed that jacking the bridge one pier at a time, and not the entire three-span unit at once, was feasible and would not cause unwanted damage.
In order to minimize traffic impacts, these jacking events were scheduled at night in 15-minute durations when traffic loads weren’t on the bridge. Local law enforcement was used to block the bridge ends when the contractor had all equipment ready, then the bridge was raised ¼ in., enough for the existing bearing to be slid out. Once the span was shimmed and the load on the jacks released, traffic reopened.
The piers exhibited cracking and spalling near the bridge bearings due to the existing bearings being partially frozen and not adequately accommodating the movement of the superstructure. The old steel fixed and roller bearings on the continuous spans were replaced with high-load multi-rotational (HLMR) bearings in order to accommodate rotational deflections and expansion and contraction in both directions. The new bearings were much shorter than the existing ones, so new pedestals were required to be poured. Base plates were designed so that the new anchor rods could be drilled and grouted into the pier cap prior to jacking the bridge due to inadequate headroom for drilling equipment if jacking was done through the pedestal. The anchor rods were terminated with couplers at the pier cap level so that the pedestals could be formed and poured with the anchor bolt extensions in place once the old bearing had been removed.
As work proceeded, the team worked closely with the construction inspectors when previously inaccessible areas revealed locations with advanced section loss. Members were analyzed to determine adequacy as section losses were discovered by the construction inspectors. In most cases, the members were found to be adequate, which eliminated the need for extra work or change orders.
The bridge bulkheads had significant deterioration caused by constant exposure to the extremely aggressive coastal environment. Fill was eroding through the open joints of the concrete sheet pile walls, causing large settled areas behind the cap. In order to replace the wall within FDOT right-of-way, temporary construction easements were obtained to install temporary sheet piling on adjacent properties to avoid damage, and the area in front of the wall was cordoned off with temporary sheet piling to minimize water current and tidal impacts to the wall during construction. The existing sheet pile wall with deadmen was removed, and new steel sheet piles were installed with sheet pile deadmen, with the concrete facing strengthened with glass fiber reinforced polymer (GFRP) rebar to provide protection for the sheet piling and provide a uniform appearance with the adjacent walls. The facing extended 3 ft below the channel bottom to provide long-term protection for the steel sheet piling, with minimal future maintenance anticipated since nonmetallic reinforcement was used in the concrete facing.
The bridge work required careful coordination with utility agencies to ensure that repairs, span jacking, and painting operations did not create problems or damage the utility infrastructure. The electric utility removed its facilities from the bridge, relocating them using a directional bore, well below the channel bottom. For the other utilities, hangers were lowered slightly to accommodate superstructure jacking operations. Abandoned utilities were removed from the bridge prior to cleaning and painting.
The south side of the bridge is located in a parking area maintained by the town of Bal Harbour and also provides the only access to and from the hotels and condominiums in the area—and access could not be closed off at any time. Construction was organized in six phases to facilitate traffic flow through the still-open section of parking. This allowed the contractor to use closed parking in sections in order to repair and install containment for cleaning and painting. Existing pavers in areas where work below-ground was to take place were carefully removed and stored for restoration at the end of construction. This was done to avoid color differences between any new lots of pavers that would have been required to be purchased.
Owner: Florida Department of Transportation, District 6
General Contractor: Kiewit Infrastructure South Co.
Colliers Engineering and Design
PRIZE BRIDGE INFORMATION
Bal Harbour, Fla.
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