FL Condo Collapse Sparks Inspection Worries


A rise of inspections and questions have surfaced in the wake of Miami’s Champlain Towers South condominium collapse at the end of last month—including worries about structures all over the country.

In Miami-Dade County, where the municipality is currently undergoing its 40-year recertification process, officials have displaced hundreds of apartment building residents over safety concerns since the collapse.

According to Miami’s Local 10 News, the collapse caused a ripple effect among residents in condominium buildings who already had maintenance concerns. After many calls and demands for property inspections, some concerns were deemed unfounded and others led to the evacuations.

For example, about 300 residents at Crestview Towers at North Miami Beach were evacuated after officials found a Jan. 11 engineers’ report that warned of safety concerns. A two-story building in South Beach was also evacuated after a flooring system failure and excessive deflection of an exterior wall was found.

The American Red Cross, along with the Miami-Dade Homeless Trust are reportedly assisting with the displacements.

As of last week, 97 people were pronounced dead as a result of the collapse with more than 150 still missing.

Concerns in Cali

The collapse in Miami led to structural and inspection concerns throughout the country. Most notably, it renewed worries about San Francisco’s leaning (and sinking) Millennium Tower, forcing professionals to step in and dispel concern.

Khalid Mosalam, a professor of structural engineering at UC Berkeley, went on the record and pointed to the differences in climate between Miami and San Francisco, as well as the age of the buildings and the differences between high- and mid-rise structures, to name a few.

However, there’s no denying that the Millennium Tower needs monitored, particularly as it undergoes its $100 million “fix,” which is slated to be completed next year.

Opened in 2008 at the cost of $350 million, the Millennium Tower was designed by Handel Architects, with structural engineering by DeSimone Consulting Engineers. Webcor Builders was the general contractor on the job, according to the Concrete Reinforcing Steel Institute.

Almost a decade after completion, in August 2016, the San Francisco Chronicle reported that Millennium condo owner John Eng had filed a lawsuit against both the building’s owners, Millennium Partners, and the Transbay Joint Powers Authority, whose nearby construction may have caused the tower to begin sinking and tilting.

In the complaint, the plaintiff calls the building “defective,” and claims Millennium Partners “knew that the Millennium and Subject Homes were not of marketable or habitable quality." The suit notes that the building sits on a manmade “mud fill” in an area that was once underwater, and asserts that the decision to build on a concrete slab and 80-foot piles instead of piles anchored into the 200-foot-deep bedrock was made “to cut costs.”

The suit also stated that, “over time the building most likely will sink an additional 8 to 15 inches into the landfill” over which it is built, and the tilt, currently measured at about 2 inches toward the northwest, could also get worse. According to the suit, cracking and buckling were also visible in individual units and in the building’s commons area.

By February 2017, a government oversight committee began conducting hearings in an effort to determine what went wrong to cause the building to sink 16 inches and tilt 2 inches. According to reports during this time, Millennium Partners also hired Sage Engineers to investigate the foundation issues and potential solutions.

That spring, the tower saga grew as the building’s homeowner’s association sued the developer and others for more than $200 million in damages to the residential structure. At the time, the lawsuit was the only one in the litany of litigation that sought a permanent fix.

Continuing into the summer, by mid-July, the NBC Bay Area Investigative Unit reported another issue with the Millennium Tower—gaps in the curtain walls of at least one unit, ultimately posing a fire hazard. Should a fire start in the unit below, it was predicted that it would easily spread upward, with high chances of causing various smoke damage.

Within the same month, the tower reportedly sunk another inch, but officials had finally reached a possible fix, should an agreement be reached. According to the LERA firm and DeSimone Consulting Engineers, the problem could be both stabilized and somewhat reversed by adding 50 to 100 new piles down to the bedrock, beginning from the building’s basement. Each individual pile would be 10 to 12 inches in diameter, noted the Chronicle. The estimated price tag for the repair was reported to be between $100 million and $150 million range, although some experts feared it would exceed $1 billion.

However, by April 2018, another proposal fix was introduced: drilling holes down to bedrock in order to stabilize one side of the tower while letting the other side sink down, allowing the building to level itself out. By this time, the tower had sunk a total of 17 inches, and tilted 14 inches to the west and 6 inches to the north. Estimations for this solution ranged between $200-500 million.

In September, several months after a retrofit repair for the Millennium Tower was proposed, another issue came to light: Cracks had appeared in a 36th-floor window, sparking concerns over whether the damage was local or symptomatic of a more widespread issue.

According to reports, the issue could have stemmed from structural issues, a material defect or be a one-off event. Architecture and engineering firm Allana Buick & Bers was hired by skyscraper residents to help determine what caused the damage.

Over time the tower’s saga has seen roughly 146 lawyers involved in nine different lawsuits filed regarding the structure’s various issues.

In September, an independent four-person panel—hired by the city and headed up by Stanford engineering professor Gregory Deierlein—after meeting 11 times with design teams from engineering firm Simpson Gumpertz & Heger for the proposed changes, approved the shoring fix.

In a letter addressed to the City and County of San Francisco Department of Building Inspections at the time, the panel—made up of Gregory G. Deierlein, Shahriar Vahdani, Marko Schotanus and Craig Shield—announced that by adding new piles to the structure, chances of future sinking should be reduced, in addition to improved seismic performance.

Since then, the plan has gone through a rigorous approval process and the fix was approved in July 2020.

Currently, the tower sits on 950 reinforced concrete piles that have been driven up to 90 feet deep into bay mud.

The process will involve drilling and jacking 52 concrete piles socketed more than 30 feet into bedrock under the north and west sidewalks. These piles would support a new mat section, or collar, tied into the existing mat.

The piles are reported to be 2 feet in diameter and weigh 140,000 pounds. The process will also relieve stress on the compressed soil located underneath the north and west sides of the building.


Tagged categories: Accidents; Health and safety; Inspection; Maintenance + Renovation; NA; North America; Safety

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