Over
the past several years, large cities throughout America and
the United Kingdom have experienced a renaissance in entertainment
facility upgrades, which in turn has led to the demolition of
many outdated sports and concert venues.
While
these high-profile projects require the destruction and removal
of large volumes of material, most present few unique demolition
challenges. By the nature of their use, the facilities themselves
are often surrounded by a sea of parking lots and open space,
and the largest concern facing a general contractor usually
involves a time deadline and the need to efficiently manage
his team's operations.
Every
now and then, however, one of these venues is located squarely
in the heart of a major urban city, and its safe demise allows
for nothing less than a precisely coordinated, delicate effort
from a seasoned team of demolition veterans. Such was the
case recently in Grand Rapids, Michigan USA when demolition
specialists at Pitsch Companies, Grand Rapids, and Dykon Explosive
Demolition, Tulsa, Oklahoma were contracted to fell the 2.3
million pound roof of the Welsh Civic Auditorium.
Constructed
in 1932 as the art-deco centerpiece of Grand Rapids, the Welsh
Civic Auditorium hosted hundreds of Big Band concerts during
the first half of the century, and later welcomed the likes
of Simon and Garfunkel and Johnny Cash among a long list of
top-name performers. The facility closed on June 1, 2003 to
allow for a $220 million renovation project designed to convert
the interior into a ballroom for the DeVos Place Convention
Center, which shares a wall with the existing auditorium.
The Welsh's original limestone facades and lobby were also
to be kept intact.
Dykon
president Jim Redyke devised a blast plan to drop the 70-year-old,
180-foot by 130-foot steel truss roof straight down onto the
building's pre-stressed concrete floor using 14 pounds of
RDX linear shaped explosive charges on a single delay. Redyke's
plan also called for meticulous preparatory operations such
as saw-cutting a three-foot wide gap around the perimeter
of the structure's basement slab (to help mitigate the transmission
of ground vibration) and covering the closest adjacent windows
and doorways with protective plywood panels and geotextile
fabric. These activities were completed on a strict timeline
under the direct supervision of Pitsch Vice President, Gary
Pitsch.
As an
added measure of security, project officials contracted Protec
Documentation Services, Hainesport, New Jersey, to forecast
and calculate ground vibration and airblast levels prior to
the demolition. The team also performed detailed pre-blast
inspections of various structures surrounding the site, including
the four-star Grand Plaza Hotel and the existing auditorium
lobby located ten feet from the roof's closest point of impact.
The blast
was scheduled for 3:00pm on a Saturday afternoon so as not
to interfere with business activities or nearby church services.
Thousands of local residents who had lined up along nearby
rooftops and the banks of the Grand River then watched and
cheered as a single sharp explosion brought the giant steel
trusses down within a majestic swirl of dust, directly onto
their intended zone. Following the blast, it was confirmed
that all adjacent buildings remained unharmed, and vibration
levels recorded at various locations were slightly less than
predicted.
