Widespread subsidence is affecting high-rise buildings along Miami’s waterfront, exacerbated by nearby construction activity, a new study using InSAR finds.
A total of 35 coastal buildings experienced subsidence of between 2 and 8 centimeters between 2016 and 2023, according to a study published in the journal Earth and Space Science.
Subsidence is most widespread in Surfside and Sunny Isles Beach, home to many of Miami’s most high-profile luxury towers.
Some of the condominiums that subsided in these areas include Eighty Seven Park, Arte Surfside, Trump Tower III, Ritz-Carlton Residences, and Porsche Design Tower, which experienced more than 10 cm of subsidence during the survey period. .
of buildings along the South Florida coast following the partially catastrophic collapse of the Champlain South condominium tower in Surfside, Florida, in June 2021, killing 98 people. Concerns about structural integrity continue.
The main cause of the collapse was the deterioration of the reinforced concrete due to inadequate maintenance and design flaws.
However, this incident highlighted the need for increased monitoring of building stability, especially in coastal areas with corrosive environmental conditions.
The study noted that South Florida’s subsidence is related to the region’s geology, which is characterized by young, porous limestone that includes dissolution features such as undulations, cavities, and sinkholes.
The authors describe the geological situation of the entire study area as “complex as the limestone may contain layered sand layers.”
Geological data suggests there is a correlation between subsidence and the amount of sand layers in the limestone, the study noted.
However, the report argues that subsidence is also related to construction activity taking place near buildings, and the authors conclude that “there is a spatiotemporal correlation between new construction in the area and subsidence.” It is observed that there is a relationship.
Most of the buildings that are sinking are new buildings built after 2014, the study said, suggesting that the subsidence is a result of the construction of the buildings themselves.
Additionally, in northern and central Sunny Isles Beach, 23% of shoreline structures were constructed in the past 10 years, and nearly 70% have experienced subsidence.
“We believe that the observed subsidence is due to long-term creep deformation caused by the loading of sand layers within the limestone, and this deformation is accelerated even if not induced by construction activities,” the study said. are.
Furthermore, “We hypothesize that subsidence is primarily due to the gradual rearrangement of sand grains within sand layers intercalated by limestone into a denser infill.
“We further hypothesize that this particle rearrangement is caused through groundwater flow in response to vibrations and pumping during the early stages of construction activities (dynamic settlement), which causes particle rearrangement. Another possible mechanism is daily tidal flow through the sand layer.”
“Rainwater injection can also cause land subsidence by rearranging sand grains and dissolving limestone.”
The study concludes that subsidence along the Miami coast is likely caused by a combination of the factors listed above and varies depending on local geological conditions.
The sources of the study were 223 SAR images acquired by Europe’s Sentinel-1 sensor between April 2016 and October 2023, and Germany’s TerraSAR-1 sensor between September 2017 and June 2021. There were 102 images captured by the X sensor.
Despite the study’s findings, South Florida’s real estate market remains strong, with several more skyscrapers planned, including the tallest building ever built in Sunny Isles.
The development, known as The St. Regis, will be 60 stories tall and more than 228 meters high. Last year, Keller completed the installation of the deepest full-length reinforcement piles ever installed in the development’s foundation.
Sunny Isles Beach had few skyscrapers until the 2000s, when a real estate boom led to the construction of luxury residential towers bearing brand names like Trump, Porsche, Armani, Ritz-Carlton, and Bentley. .
It is now a densely developed area, ranking as the 14th city in the United States for buildings over 500 feet tall, according to data from The Skyscraper Center.
