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11 bridges on historic Venetian Causeway to be demolished and rebuilt

Everyone’s an Island: On April 9, people took a self-guided hidden history tour of the Venetian Islands can either be walked, biked, or driven. After attendees finished the route, we’ll meet at Belle Isle park for a poetry reading.

MIAMI (AP) — The die has been cast: The 11 original bridges on the scenic and cherished Venetian Causeway, which is just three years shy of its centennial, can’t be saved and will be demolished.

Under a $148 million Miami-Dade County plan recently ratified by Florida and federal highway officials, the historic but badly deteriorated bridges along the Venetian, completed in 1926, will be replaced by higher spans designed to withstand rising seas and more potent storm surge due to climate change.

In an acknowledgment of the causeway’s historic import — and the uniquely close-up and sweeping views it affords of Biscayne Bay — the plan requires that the new bridges replicate the look, scale and feel of the old, down to the arched supports and the open, cross-hatch patterns of the concrete bridge railings.

“Without a doubt, the bridges are in poor shape,” said Josenrique Cueto, deputy director of the county’s public works department, which maintains and operates the Venetian. “There is no doubt the bridges need to be replaced. But this is a marquee project and requires a special level of care.”

The new bridges will have an expected life span of at least 75 years, county engineers said.

Work on the massive project, eight years in the planning, won’t start anytime soon, though.

Design work, led by EAC Consulting of Miami, is only about 30% done and will take until spring of 2025 to finish, Cueto and his engineering team said. Because of the time needed to select a contractor and secure permits from numerous regulatory agencies, demolition and construction would not begin until 2026 at the earliest, they said.

MOSTLY UNINTERRUPTED ACCESS

The reconstruction is then expected to take four years. County engineers say they are planning a creative approach — demolishing and building half of each bridge at a time — to ensure mostly uninterrupted access across the causeway. They say there will be one open lane of motorized traffic in each direction and one sidewalk, albeit a narrow four-foot one to be shared by pedestrians and cyclists, throughout construction.

The decision to demolish comes after eight years of painstaking analysis and public debate over what to do about the 2.5-mile-long causeway’s failing and corroded bridges, which connect the six residential Venetian Islands and the cities of Miami and Miami Beach. On many of the bridges, steel plates cover weak spots or holes left when chunks of road decking fell into the bay in recent years.

Preservationists and historians, who consider the Venetian one of Miami’s key historic landmarks, had urged the county to consider saving the existing bridges and repairing and retrofitting them. That’s the view that prevailed when the bridges were last fully refurbished in the mid-1990s. Bridge supports were repaired and reinforced while the concrete railings were stripped off and replaced with reproductions that met modern safety standards while closely mimicking the originals.

But the bridges soon began falling apart again, in part because of higher seawater levels in the bay, which accelerated corrosion and also magnified the effect on the support beams of stronger wave action during storms. Just 15 years after the rehabilitation, all 12 bridges scored poorly in engineering evaluations. The westernmost span, a drawbridge at the Miami end of the causeway, was in such bad shape that it was fully replaced in 2016.

IMPRACTICAL TO RENOVATE BRIDGES

Given that experience, county engineers and consultants ultimately concluded it would be impractical to renovate the remaining bridges, and state and federal officials concurred. In December, the Florida Department of Transportation and the Federal Highway Administration gave the county the green light on a jointly developed plan to replace all 11 remaining original bridges — 10 fixed spans and the easternmost drawbridge, which connects Rivo Alto Island and Belle Isle, the closest to mainland Miami Beach.

The lengthy study, complicated by environmental concerns as well as engineering needs, also tackled the question of how best to safeguard the causeway’s historic qualities, while completely rebuilding the bridges and decorative features that provide its essential characteristics.

The compromise that was worked out, said Miami Beach historic preservation director Deborah Tackett, incorporates rigorous standards in the plan to ensure the rebuilt causeway replicates the original as closely as possible. The plan also calls for four prominent markers along the causeway detailing its history and significance.

The Venetian, the oldest causeway in Florida, replaced a wooden bridge across the bay that was built in 1913 by Miami Beach developers John Collins and Carl Fisher. Dug-up bay bottom provided the material for construction of four of the six artificial Venetian isles, as well as five tiny spoil islands that provide landing spots for bridge supports.

The causeway is protected as a historic landmark by the cities of Miami, which has jurisdiction over its westernmost two islands, and Miami Beach. Historic preservation boards in both cities would have to approve demolition, as well as the final design of the bridges.

The Venetian is also listed on the National Register of Historic Places, an honorary designation that does not confer legal protections but does qualify the causeway for certain preservation grants.

The fact is, Tackett said, that the causeway is not identical to the 1926 original because the 1990s renovation replaced railings and lights with modified designs to meet then-current engineering standards.

“Here we are again, basically,” Tackett said. “A lot has changed since 1995 in terms of our awareness of climate change. It hasn’t held up that great. It does not meet today’s needs.”

That doesn’t mean the causeway will lose its historic designations, however, so long as the reconstruction hews to the standards in the plan, she said. The city of St. Augustine, she said, replaced a historic bridge some years ago, but it still retained its national historic register listing.

“It’s a philosophical question, really,” Tackett said. “If you inherit your dad’s hammer, and you replace the wooden handle, and later you replace the metal head, is it still your dad’s hammer? There is no wrong answer.

“For the Venetian, it’s not just the structure that matters. It’s the entire history of the site and the structure. It’s more than just the architectural features that make this a historic site. It’s an important part of our history that helps educate about the development of Miami Beach and Miami.”

CLIMATE CHANGE CONSIDERATIONS

Preliminary estimates, subject to change as design advances, put the full cost at $148 million. Most of that will be covered by state and federal money, county officials say. The county has so far allocated $19.5 million towards planning, design and construction. The work also includes replacement of water and other utility lines that run beneath the bridges.

The new bridges will be more firmly anchored with deeper foundations in the bedrock — and those will consist of drilled and filled supports instead of pilings pounded into the ground to minimize construction noise, as well as environmental impact on the bay. Those deeper foundations will increase the bridges’ resistance to the pounding waves from storm surge that, according to an engineering report, could sweep away the shallow supports of the existing bridges — another factor in the decision to replace them.

The fixed replacement bridges will be at least one foot higher than the old ones, or just slightly above that, depending on location. That additional height is enough to protect against sea-level rise while maintaining the causeway’s picturesque, vintage look and minimize the effect on nearby houses on the densely developed Venetian islands, county officials say.

Lifting them more would have required also raising the roadway where it meets the bridge ends on the residential islands to provide the right approach grade, an effect on homeowners that planners wanted to avoid. As it is, the taller bridge landings, especially for the new drawbridge, could restrict what’s now easy ground-level public access to the compact, low-lying spoil islands. Engineers say they will identify areas where walkways can be built to provide pedestrians access down to the islands from the higher bridge ramps.

The drawbridge replacement, meanwhile, will be almost three feet higher than the existing span. That will not only provide greater clearance for storm surge, but also for boats, reducing the need for drawbridge openings.

The new fixed spans also will be widened by 16 feet. That’s to accommodate wider sidewalks and separate, buffered bicycle lanes to improve safety for the thousands of runners, pedestrians and cyclists who use the causeway every week for recreation and commuting. The widths of the raised sidewalks will double to eight feet. The new bike lanes, at roadway level, would be seven feet wide, or three feet wider than the narrow and crowded existing lanes.

“Sea-level rise considerations and greater resiliency were a primary item,” said Gabriel Delgado, a county engineer on the project. “We also know we are facing a heavier use, heavier vehicles and heavier pedestrian uses. It’s heavily used by pedestrians and bicyclists, and it’s used for commerce, by emergency services. This will also make the bridges safer and more efficient for those users.”

The bridges also would collect polluting rainwater that now runs off into the bay and channel it away for treatment.

EXPECT YEARS OF TRAVEL DELAYS DURING RECONSTRUCTION

County officials conceded the start of work will mark the start of years of travel delays and disruptions for motorists. Most affected will be Venetian Island residents and the runners, pedestrians and cyclists who daily cross the causeway, as well as the Metrobus route that connects the downtown Miami Omni transit station to Lincoln Road in South Beach. The project could also affect the annual Miami Marathon, which uses the Venetian as a key link on its course.

For Venetian residents, the price of living in paradise has been a near-constant spate of causeway and road maintenance and repair projects. A decade ago, residents and causeway users endured two years of partial closures and ripped-up roads as the county resurfaced and beautified the island portions of the Venetian. Just two years later, the drawbridge replacement project cut off direct access for nine months between Miami, the islands and Miami Beach.

Right now, the Venetian Way is shut at two spots north and south of the bridge connecting Belle Isle and Rivo Alto Island for several months as underground water mains are replaced in a $5.4 million project. Motorists, cyclists and pedestrians must detour through island streets.

But the engineers say the half-a-bridge-at-a-time approach will significantly minimize interruptions. Work will likely progress from east to west, one or two bridges at a time, the engineers said.

The drawbridge, however, can’t be built that way. So engineers will install a temporary floating bridge alongside it before demolishing the old span.

The one drawback to that approach is boaters can’t get through and will have to take a long roundabout detour to the westernmost drawbridge on the Miami end to traverse the bay north and south.

The county engineers stress there will be numerous public meetings to vet designs and air concerns, as well as environmental and other permitting reviews by regulating agencies like the U.S. Army Corps of Engineers and the U.S. Coast Guard, before a final plan is approved and set in motion.

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