Services »
Search »
Step By Step »
The Kingdome consisted of two main categories of construction: Structural, which held the building up, and support construction, which could be pre-removed.
The structure consisted of poured-in-place, pre-stressed and post-tensioned concrete elements.
Nonstructural ramps, slabs, and siding were removed to reduce the amount of debris that fell to the ground.
Explosives were placed in the structure at key locations.
Demolition of the main structure occurred in two phases of a single implosion sequence. Explosives in the Phase 2 areas were detonated several seconds after Phase 1.
Special material wrapped the structure at the blast points to control the explosion.
Small explosions fractured the rigid concrete allowing the structure to buckle and fall. The flexible rebar remained intact, acting like ropes to pull the columns toward the center.
Gravity did most of the work.
Phase 1 continued to fall, helping to pull Phase 2 in. Phase 2 was detonated several seconds later and collapsed and fell the same as Phase 1.
More explosions further fractured the concrete into smaller pieces.
About 20 seconds after the first explosion, the entire structure collapsed with all of the debris falling within the Kingdome footprint.
The detonation area provided latitude around the entire perimeter for structural debris to fall adjacent to the footprint, but still within the demolition site.
Crushed concrete berms were placed across the Kingdome playing field surface to cushion the fall of the roof. Debris on top of these berms in this area was approximately 25 feet high.
Debris from the perimeter columns and seating construction fell mostly straight down or inward, averaging piles less than 60 feet high.
Click Here to watch the video.