![]() ![]() Those sounds came in intermittent intervals for at least 15 minutes prior to the collapse, suggesting to engineers there were multiple pieces of rebar failing one after another. the investigation began to focus on an initial failure of internal rebar, since none of those witnesses saw any evidence of concrete failure. For this and other reasons, the results of the Herald/UW model represent an important step in understanding a possible collapse scenario but not the definitive result.īased on the accounts of six witnesses who first heard a series of booms culminating at 1:14 a.m. As such, the Herald reference model is based on the limited information available in the 1980 structural drawings, including the specified design strengths for the concrete and the reinforcing steel.įederal investigators with the National Institute of Standards and Technology will be able to make a more accurate model based on actual conditions as they probe the collapse debris and other data, including concrete core and rebar samples, which would help in gauging water damage that occurred over time. While it’s generally agreed that a model based on the actual conditions of the building prior to collapse would be more accurate in predicting the structure’s behavior, the Herald could not take that approach as the team did not have access to the site to conduct necessary tests. Each simulation mapped the resulting vertical deflections (downward movement of the slab), concrete cracking and steel stresses - conditions that could have been conducive to a collapse. Using this model as a reference point, a single parameter was changed to investigate the impact on the damage pattern and progression. ![]() ![]() Use computer modeling to test whether that origin could lead to the kind of progressive failure observed in post-collapse photos, specifically to check that the resulting damage would spread both all the way south to the pool deck perimeter AND into the tower itself.įirst, the Herald/UW built a model of the structure as designed to provide a baseline for comparison.Identify possible points of origin through an analysis of witness testimony, structural drawings, inspection reports and photos of post-collapse damage, including broken, corroded rebar.And the team at UW began to look for possible collapse sequences that began with rebar failing in a sequence, followed by a rapid collapse of the deck.Ĭomputer modeling involves a process of trial and error, testing and evaluating the feasibility of different scenarios.Įstablish a baseline for comparison by modeling the stresses on the level-one slab before the collapse and use the model to identify overstressed regions that might be susceptible to collapse. This timeline provided the basis of the Herald’s forensic analysis. Computer model, witnesses reconstruct the tragedy. SURFSIDE INVESTIGATION The last stand of Champlain Towers South. People heard the sounds on the first floor and in the basement but saw nothing, likely indicative of an initial rebar failure. The loudest and final booms in the series came at 1:14 a.m. First, there was a series of intermittent but distinct - and increasingly loud - booms from just before 1 a.m. The witnesses described the collapse sequence as a three-part failure, each with distinct sounds that engineers can use as clues when they try to piece together what happened. The Herald partnered with University of Washington engineering professor Dawn Lehman to build a computer model and explore the following critical questions raised by their experiences: Where exactly could this collapse have started and how did it spread across the pool deck and into the tower to become one of the deadliest collapses in modern history? But a recent Miami Herald investigation based on 10 key eyewitness accounts found the collapse began somewhere on the pool deck seven minutes before the northern wing of the residential tower fell. The grainy security footage released hours after Champlain Towers South crashed to the ground left many assuming the tower went down without warning in mere seconds. Here’s what it showed The team that built the Herald’s engineering models for Champlain Towers Computer model, witnesses reconstruct the tragedy The collapse reconstructed: Ten witnesses describe what they saw and heard ‘Lives would have been saved’: Fire alarm didn’t go off before Surfside tower collapse The Herald built a computer model to explore how Surfside tower fell. The last stand of Champlain Towers South.
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