For a long time, the Pontiac Silverdome emergency arena in Detroit, the former home of the Detroit Lions hockey team, has not collapsed after the planned circular undermining. This can be seen from the video of the incident.
As a result of the blast, only the beams that held the arena were collapsed, but the building itself stood.
As the explosives say, it happened because not all the charges were detonated. Experts believe that in the near future the arena can collapse by itself, and if this does not happen, it will be destroyed by special equipment.
Source: LIGA.