DAVENPORT, Iowa — News 8 reached out to structural engineering experts from across the country to get their initial reactions and early observations of the Davenport building collapse.
Engineers were quick to note the building's age, which is over 100 years old, stating that old buildings can often have structural problems that are hard to determine solely by visual inspections.
"At the time these were built, there were really no building codes — and so each building is different," structural engineering professor Roberto Leon from Virginia Tech said. "Even if you have the plans for the building, it's not clear that it was constructed that way or if it's been changed in any way."
Leon added that older buildings are often neglected because of the exhaustive costs needed to improve structural health, which can be even harder if there is a historic designation on the building.
“Trying to take an existing building like this and bringing it up to code today is, I can tell you it’s almost economically impossible,' Leon said.
At the City of Davenport's Tuesday morning press conference, the city's consulting structural engineer Larry Sandhaas said that the rubble pile at the base of the collapsed side is stopping the building from collapsing, and that disturbing the rubble or clearing it to search for more survivors could risk bringing the entire building down.
Leon agreed that an unstable building is dangerous and that it's plausible the rubble pile could be holding the building up.
"The building as it is there, you left it alone there, could stand a hundred years or come down in the next ten seconds," he said. "There is nothing more dangerous than moving a pile of things that's probably holding up the rest of the building."
Alan Jeary, a structural stability expert of over 40 years, agrees. "Yes, they may well be right that the rubble itself is adding stability to part of the building," he said.
Both engineers expressed sympathy over the need to search for more survivors and said the situation is a difficult risk assessment.
"If they're saying it's an idea to demolish the whole building rather than take little bits out, because you might get a partial collapse under those circumstances, then I'm sympathetic to what they're saying — it could be very dangerous," Jeary said. "At the same time, human life — if people are still inside, underneath rubble — you still want to save them and pull them out, and the earthquake in Turkey suggests it's not too late yet."
Jeary pointed out the various complaints from tenants on the building's condition. "There were a lot of red flags there of things that were happening," he said. "They saw cracks opening up, they felt floors subsiding, they heard creaking."
He explained that visual condition issues don't necessarily indicate structural failure, but when combined with the building's age and the need for exterior repairs, he said engineers should have considered further testing.
"The techniques are available right now to assess the capacity of the structure," he said. "With a six-story building, we can do it within one day."
That method involves special sensors placed around a building, which monitor small vibrations. Vibrations caused even by subtle movement of the wind or traffic passing by are enough to pick up data, which can help reveal unstable portions of the building. "Once you can do that, you avoid the possibility of a horrific collapse," Jeary said.
Jeary and his colleague Thomas Winant, who both run structural analysis company STRAAM Group are encouraging more engineers to use technology like this, saying many engineers aren't even aware of newer testing methods.
"I think as a society, we have an opportunity now to raise the bar, and there has to be an interest from building owners and engineers," Winant said.
All three engineers noted that the repair work being done on the façade that collapsed could have contributed to the chain of events, but it's too early to determine a main cause. They added that a main cause might not be determined for years, as the 2021 condo collapse in Surfside, Florida for example is still being investigated.