by Portland-based engineering firm KPFF found the snow was only a minor contributor to the collapse.
Structural engineer Katie Ritenour told the Medford School Board at a meeting on Thursday night that one cause of the collapse was that some major glue-laminated beams, or glulams, failed along the diagonal line where they were glued together, called scarf joints.
"When looking at the damaged timber, we also saw a lot of failed scarf joints," she said. "What these failed scarf joints did is they showed a pretty clean failure plane indicative of the failure being in the glue line and not in the timber."
But, she said, the precise cause of that failure is difficult to determine.
"It's hard to say if it was the glue or it was the manufacturing, how that was kind of compressed and glued together at that time," she said.
"It is not uncommon to find pre-maturely failed scarf joints in glulam beams from this time period," KPFF's evaluation reads.
In addition, Ritenour said engineers have learned more about glulam beams since the gym was built in 1965. The roof was overstressed by 10% across its lifetime, and potentially up to 40% with the snow on top.
Other minor factors contributing to the collapse were the snow and how the basketball hoop was installed.
Ritenour said the current code would not allow the hoop to be connected to the bottom third of the glulam beams.
"Because of this, the basketball hoop connection could have caused local damage to the glulam beam lower laminations that could have contributed to lower strength," she said.
Ritenour said various other causes of the collapse were investigated and ruled out, including the roof's seismic upgrades in 2024 and problems with the roof drains.
The district has tried to clarify the causes of the collapse amid spreading misinformation.
"There has been a lot of speculation and people who are claiming to know facts when in fact they haven't," Superintendent Bret Champion said.
The district still plans to rebuild the gym and says designed development is in the works.
