Tuesday, August 3

Miami Condo Collapse Raises Questions About Climate Change Role | Miami condo collapse


The shocking collapse of a 12-story building in the Miami area last week has raised questions about the role played by the climate crisis and whether South Florida’s severe vulnerability to rising sea levels could lead to the destabilization of more buildings in the future.

The exact cause of the disaster that occurred Thursday at the Champlain Towers South building in Surfside has yet to be fully determined, though a 2018 engineering report on the structure it warned of “significant cracks and breaks in the concrete” and that design flaws and deterioration of the waterproofing could cause “exponential damage” through the expansion of these cracks.

At the time of the building’s sudden collapse, repairs were underway to its roof, but concrete restoration had not begun on the 40-year-old condo. A total of 10 people are confirmed dead due to the collapsed building, with 151 people missing.

The disaster has highlighted the precarious situation of the construction and maintenance of high-rise apartments in an area under increasing pressure from rising sea levels. Experts say that while the role of rising sea levels in this collapse is still unclear, the integrity of the buildings will be threatened by the advance of salt water pushing up from below to weaken the foundation.

“When this building was designed 40 years ago, the materials used would not have been as strong against the intrusion of salt water, which has the potential to corrode the concrete and steel in the foundations,” said Zhong-Ren Peng, professor and principal. of the University. from the Florida International Center for Adaptive Planning and Design. “The cracks in the concrete allow more seawater to enter, which causes more reactions and the extent of the cracks. If you don’t take care of it, it can cause a failure in the structure. “

The geography of the area can also be a challenge for construction.

Champlain Towers South was built off the coast of what is a narrow barrier island flanked by the Atlantic Ocean on one side and Biscayne Bay on the other. These barrier islands change position naturally over time due to the hit of the ocean, requiring a certain amount of engineering to hold them in place.

Most of South Florida is just a few feet above sea level at a time when the region is experiencing a rapid rise in sea level due to the man-made climate crisis. To compound this problem, the region sits on limestone, a porous rock that allows seawater to bubble up from below.

This scenario means that Miami residents have become accustomed to flooded car garages and water seeping from drains onto roads, even on sunny days. The city is planning to build a new boardwalk to keep the ocean at bay, but there is no simple defense against water rising underfoot, putting the foundations of buildings at risk of being gnawed by seawater.

The land beneath Champlain Towers South too, unusually for eastern Florida, is declining, according to a study published last year that found the condo was sinking into the ground at a rate of around 2mm per year for the decade. 1990. Shimon Wdowinski, a professor at Florida International University’s Institute of the Environment who conducted the research, said he was “shocked” to see the building collapse and did not immediately link it to his study.

“It’s common for us to see buildings with minor subsidence damage, but not really this,” he said. “Things can become stable and move slowly over a long period of time before suddenly accelerating to the point of collapse. It is not a linear process. “

Peng said building code updates in the wake of Hurricane Andrew, a category five hurricane that hit Miami-Dade County in 1992, have made new structures more resilient against major storms.

“But older buildings are still at risk and in any case the new building codes may need to be reexamined because they don’t address the problem of rising sea levels,” he said. “I think that, at a minimum, all new developments should be required to carry out a study on the impact of sea level rise before construction is complete.”

However, the challenge for Miami will continue to increase.

The region borders seas that are around 20 inches higher than a century ago and this rate will accelerate, with another 17 inches of sea level forecast for 2040. Depending on the melting of the vast ice sheets of Greenland and Antarctica, South Florida could be assaulted by a additional sea level feet per decade in the second half of this century, according to Harold Wanless, a geographer at the University of Miami.

“It will be a huge or impossible job everywhere to deal with that,” Wanless said. “Sea level rise is accelerating and will do so more dramatically than most people anticipate.

“Every sand barrier island, every low shoreline, from Miami to Mumbai, will be flooded and it will be difficult to maintain a functional infrastructure. You can put valves in the sewers and in the seawalls, but the problem is that the water will continue to rise through the limestone. You’re not going to stop this. “


www.theguardian.com

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