The Rialto Apartments: Large gap found between soil, building's foundation, engineer reports say
ORANGE COUNTY, Fla. - A soil gap measuring 15 feet wide has caused a section of The Rialto apartments to shift, forcing Orange County officials to post "no occupancy" signs and evacuate residents while repairs are underway.
Needed repairs may take longer than 60 days to complete – depending on the contractor's availability and time required to process laboratory samples, engineers said in an April 1 report.
At this time, there's no immediate concern that the structure will fail. However, it's not suited for continuous resident occupancy while repairs are underway, the report said.
The backstory:
Residents began calling 911 around 4 a.m., March 19, claiming that their doors had been jammed and that they were unable to open them. Another caller, officials said, said she could hear "popping noises" and feared the 5-story apartment building was going to collapse.
Hundreds were evacuated from an apartment building in Orange County on Thursday, March 19, after potential concerns with the building's stability.
The Rialto – located on W. Sand Lake Road – is part of a mixed-use building, where several businesses are located beneath the apartments. Businesses located under the apartment units were also evacuated.
A report from the Structural and Geotechnical Investigation said popping noises were reported in a fifth-floor unit – in which front doors were jammed and were subsequently opened by fire crews. Two doors in the apartment stacks were also stuck, the report said.
Upon news of the structure concerns, Northalnd Rialto LLC hired a firm to investigate the cause of the event.
Issues identified at The Rialto
What we know:
The building stacks – stacks 45 and 47 – were primarily affected, causing a number of structural concerns – leading to doors jammed and floors sloped.
Here are a few issues identified by engineers:
- Several gaps between the concrete slab and underlying soil – ranging from 0.5 to four inches deep – were found.
- A three feet deep and 15 feet wide in diameter gap was found between the soil and the ground-level slab that extends underneath the load-bearing wall footing between stacks 45 and 47.
- The report said it's believed that a lack of soil below the slab-on-grade foundation between these stacks resulted in the downward movement of the slab and wall.
- Engineers observed cracks in the drywall of stacks 45 and 47, jammed doors and floors that sloped toward a shared bearing wall between units 45 and 47.
"Our initial observations indicated that a portion of the building had likely been displaced or otherwise moved downward," the report said.
Hundreds were evacuated from an apartment building in Orange County on Thursday, March 19, after potential concerns with the building's stability.
What is the building's design?
According to the engineers' report, original construction drawings of The Rialto show parallel chord-wood tresses at the roof and on each floor supported by conventional wood-framed bearing walls. The walls are supported by a four-inch thick ground-level concrete slab with post-tensioned reinforcement.
Orange County Division of Building Safety responds
In an April 2 statement from the Division of Building Safety, the county provided next step plans regarding The Rialto.
"At this time, we have clearly posted ‘no occupancy’ on the affected structures until all repairs have been permitted, inspected, and occupancy reinstated, or the engineer deems the building or portions thereof as safe to occupy.
"The investigating engineer has ordered temporary shoring work, which will commence as directed. We have asked for a detailed list of all required emergency repairs and, when completed, documentation that the temporary repairs or shoring have been installed in accordance with their design. We may inspect the temporary shoring measures once that stage is reached. At this time, no timeline can be provided for the shoring work or for when an inspection may occur.
"After that, they will continue with the subsurface investigation and structural analysis. The preliminary engineer letter states, "The anticipated duration of this work is uncertain but may exceed sixty days".
"Once the investigation is completed, engineered plans for repairs will need to be submitted as part of a permit application. Our team will assist with permitting and inspections and support the customer until the final inspection and certificate of occupancy have been issued."
Hundreds were evacuated from an apartment building in Orange County on Thursday, March 19, after potential concerns with the building's stability.
What's next:
Engineers are in the process of developing a floor plan, in which the approximate size and extent of the gaps are identified, the report said. A high priority is to install temporary shoring supports to the ground-level slab in the 45/47 stack. There's currently no timeline for the shoring work.
Engineers will also conduct a subsurface investigation in and around the building to determine the cause of the gaps and any future gaps that could develop. Geological surveys will also be performed, the report said.
Per the Division of Building Safety’s released statement, once the investigation is complete, engineers will need to submit a permit application detailing the repairs needed.
The Division of Building Safety continues to provide assistance until the final inspections and certificate of occupancy are issued.
The Source: Information in this story was gathered from the Orange County Division of Building Safety and a Structural and Geotechnical Investigation report from the city of Orlando.