Quick fix coming for Aberdeen bridge
May 26, 2009
Nicole Macintyre
The Hamilton Spectator
http://www.thespec.com/News/Local/article/572041
The bridge connecting Aberdeen Avenue to Highway 403 will disappear next summer and reappear within 48 hours.
Call it a concrete magic trick.
The aging overpass has been selected by the Ministry of Transportation for rapid bridge replacement, an innovative engineering technique that has only been used a handful of times in Canada.
It would take two construction seasons to replace the bridge the old-fashioned way.
"This will be one weekend when traffic is impacted, instead of 12 to 18 months," said Ministry of Transportation spokesperson Will MacKenzie.
"It's a much more complex process."
The Aberdeen replacement is part of a two-year plan to rehabilitate eight local highway bridges and ramps, including York Boulevard, King and Main streets.
The ministry has yet to put a price tag on the massive project, which is about to be tendered. Work will be staggered from next summer to 2012.
Drivers can expect delays throughout the process, which will require some lane reductions and ramp closures. However, MacKenzie said the ministry will only work on one access at a time to limit the headache for drivers.
"It will be one after another."
Most of the bridges were built in the 1960s and have undergone few upgrades in the subsequent decades. Ministry consultant Edward Li said the structures are in poor condition with failing road surfaces, damaged and leaking joints and deteriorating supports.
The Main Street overpass was also damaged by fire in 2003.
Though there have been emergency repairs to the structures over the years, Li said a major overhaul is needed.
The Aberdeen bridge had to be closed temporarily in 2007 after a road crew discovered a hole in the deck. MacKenzie said the overpass is a perfect candidate for rapid replacement because it's made of concrete, while the other bridges have major steel parts.
Though rapid replacement is becoming increasingly popular south of the border, it's still rare in Canada. The technology has been used twice in Ottawa to replace bridges on the busy Queensway.
The Aberdeen project will be the first multi-span replacement in the country.
Michel Vachon, who was the structural design manager with McCormick Rankin for both Ottawa projects, said the technique reduces the environmental impacts of construction, such as air emissions, and the economic consequences of traffic congestion.
"In this case, there was high risk, high reward."
During a rapid removal, construction crews remove the old bridge using self-propelled modular transporters, which can lift loads as heavy as a fully loaded Boeing 747. The new bridge, which is made nearby, is then moved into place like a puzzle piece. Correct measurements are critical, said Vachon, noting the bridge's design allows for adjustments.
The first process in Ottawa in 2007, which took less than a day, drew more than 1,000 spectators. It also attracted the attention of the Discovery Channel and was broadcast live on the local TV station.
Timeline for repairs
Aberdeen Avenue: one weekend, June to August 2010
Main Street: 12 weeks, spring-summer 2010
King Street: six weeks, July to August 2011
York Boulevard: 16 weeks, spring-summer 2012