ALLEN, Texas -- Portions of a $60 million Texas high school football stadium that opened just two years ago may have to be demolished and rebuilt after structural flaws were found.
A report by Plano-based Nelson Forensics says cracks found at Eagle Stadium in the Dallas suburb of Allen may be caused by substandard concrete work and improper structural design of reinforcing steel.
"The cracking has decreased the service life of the structure and potentially decreased its structural capacity," the report states.
The firm told Allen school district officials it tested three concrete samples and found dark paste that's typical of poorly cured concrete, which can erode durability.
The firm presented its preliminary findings in January at the request of the Allen district. The report was released Wednesday to The Dallas Morning News after an open records request.
Allen officials closed the 18,000-seat stadium last month after discovering the cracks in the concourse.
CBSDFW.com reported the cracks were first noticed when the stadium originally opened. Since that time, those cracks have multiplied and grown wider -- in places they are one-quarter of an inch to three-quarters of an inch wide.
Houston-based PBK Architects has denied the problems are a result of any flaws in its design. Pogue Construction in McKinney, which built the stadium, has declined to speculate on the problem but says it's working with the district to resolve the matter.
The report by Nelson said water had seeped into an elevated floor joist system, making it weaker. It suggests the possible causes include "improper concrete placement, improper concrete finishing, improper concrete curing and improper structural design of reinforcing steel to control shrinkage cracking."
The firm suggests replacing concrete slabs and performing additional work to the floor joist system. Replacing the affected flooring system will prolong the stadium's life but will be costly and take months.
Other options include epoxy injections to seal cracks. That would be faster and less expensive, but would diminish the stadium's aesthetics and require periodic repairs and reapplications, according to The News.
School district officials say it's possible the stadium will remain closed next school year because Nelson won't finish its full review until June.
The rest of Nelson's work is estimated to cost $100,000 and will include a detailed review of the stadium's design, construction documentation and other work.