The implosion: pushing the button

The implosion will take place in two phases, collapsing the Dome in six sections. Explosives in three sections will be detonated, followed several seconds later by detonations in the remaining three sections. Detonation will begin when an electric pulse is sent through two wires encircling the Dome, setting off six electric charges. The charges will ignite the network of orange detonation cords that will burn up instantaneously in a bright flash lighting the fuses to the explosives. Timed groups of explosives will then go off at different intervals.

Phase one
A sequence of small explosions in the first three sections will fracture the concrete in the ribs, columns and supporting tension ring. The flexible rebar that runs through the concrete will remain intact. As the heavy concrete roof drops, the rebar will act like ropes pulling the columns down and toward the center.

Phase two
As the first sections fall, the next three sections will be detonated and collapse, bringing the center compression ring down with them.

Gravity takes over
The entire procedure will take nearly 20 seconds, with about 12 seconds of actual explosion time. The structure will have collapsed inward, with the pile of debris at the center as high as 25 feet and the perimeter debris, including columns, as high as 60 feet.

After the implosion
Three work crews will clear the remaining pile of rubble. Large pieces of material will be broken down further and the top of the pile will be brought to grade level. Steel reinforcements will be separated from the heap for recycling. Foundations that conflict with new construction will be removed.

Of the initial 130,000 tons of material that made up the Dome, 80,000 tons were recycled onsite or hauled away before the implosion. Of the remaining 50,000 tons, most of which will be concrete, 35 percent will be used onsite as backfill for the new stadium. The rest will be sold as recyclable material.

Graphics and text: Phil Loubere; Reporting and text: Whitney Stensrud; Reporting: Jeff Hodson / © 2000 The Seattle Times

Copyright © 2000 The Seattle Times Company