So far, some engineers have focused their attention on the upper bars of rebar because it is difficult to tell which lower segments of rebar would have gone through the columns and would therefore be visible in the wreckage after the slab dropped. Rubble may hold the most important clues to what happened.
Mr. Kilsheimer said, “We have a whole bunch of issues that we think might be part of or the trigger of what happened.
Engineers found more than one potential issue with the steel reinforcement during their initial assessments, including the surprisingly low amount of rebar visible after the parking slab collapsed.
Structures that had been ripped from the concrete could be seen dangling from the remaining structure, according to University of Washington structural engineer Dawn E. Lehman.
She speculated that this could be an indication that the concrete was damaged in some areas and that the steel did not have a strong enough bond with the concrete. If corrosion, concrete degradation, shearing damage or use of rebar with weaker bonding properties are all possible explanations for this, she said.
To better evaluate the building’s components, Mr. Kilsheimer said he hoped to see more of it in the coming days. Concerns have been expressed about the dangers posed by the remaining structure. Kilsheimer said computer simulations indicated that a large portion of it was at risk in high winds, and he was concerned about that.
According to Mr. Kilsheimer, the building’s concrete and steel will be tested at some point, and the soil will be examined and tested with borings, too. In an off-site storage facility, they’ll use computers to model the building and piece together the rubble-recovered components.
According to him, trying to solve the mystery is like throwing a bunch of puzzles into a room, “brooming them all together, and then putting them back together again.”Surfside, Florida-based Lazaro Gamio contributed to the story.
