An engineer hired to help figure out why a South Florida condominium collapsed last month is warning officials that the site may still not be safe.
Structural engineer Allyn Kilsheimer told Surfside and Miami-Dade officials in a letter Thursday that Collins Avenue could crumble because a remaining perimeter wall near the road could fail.
“We believe there is a potentially dangerous situation at the site, where the wall is in danger of collapse,” Kilsheimer wrote.
All that remains of the Champlain building are the walls of the underground parking garage, around a hollowed-out foundation, and Kilsheimer says that without more support for those walls, nearby traffic could make them collapse, with parts of the street falling into the void.
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“If the wall were to collapse or rotate substantially, the retained soil under the street and sidewalk could move with it,” wrote Kilsheimer, of KCE Structural Engineers.
He recommends building an earthen berm to support the walls near the street and sidewalk. Otherwise, the movement “could cause portions of the street to collapse and could seriously compromise the utilities under the street,” he wrote.
Miami-Dade County is bringing in crews to help shore up the remaining underground walls, Rachel Johnson, the county's communications director, told the Herald.
“We are moving to procure a company to do shoring and bracing of the walls to assure there is no risk,” she said.
Miami-Dade Mayor Daniella Levine Cava announced Friday the plan on when to reopen Collins Avenue is being “reevaluated… until we are confident all needed steps have been taken to assure the public’s safety.”
“We are taking the potential concerns outlined in the letter extremely seriously,” Cava said in a statement. “That’s why we moved immediately to contract with a company that will do shoring and bracing of the walls to mitigate any possible risk.”
Cava’s office did not answer questions about whether reopening just part of the road, on the west side away from the shoring concerns, was an option, or how long shoring and bracing would take.
The National Institute of Standards and Technology, a federal agency investigating the collapse, has been monitoring the site's safety.
Collins Avenue, which is the major thoroughfare on the barrier island, has been closed to traffic near the site since June 24, when the building partially collapsed, killing at least 97 people. Town officials had said Collins Avenue would be opening soon.
In the letter, Kilsheimer said heavy rain would increase the risks substantially because the ground becomes saturated with water.