In their competing accounts of what went wrong before last year’s Florida pedestrian bridge collapse, both the contractor and designer agree on one point: The concrete was never “roughened” at locations where it was required. The process involves altering the material to promote mechanical bonding. Among the most important locations were the key junctures where bridge truss diagonals and verticals met the bridge deck.
The March 15, 2018, collapse of the span at Florida International University in Miami is believed to have begun at the construction joint where truss members 11, a diagonal, and 12, a vertical, meet with the bridge deck in a node near the bridge’s north end.