INNOVATION July-August 2013

Bridge over Lhomond River, Haiti In Canada, bridges are something we take for granted. In Haiti, bridges are far less common, and in rural Haiti, most people must ford the rivers. But now, thanks to a partnership between Rapid-Span Structures and the St. Boniface Hospital in Haiti, a new bridge crosses the Lhomond River. The 35 m long all-steel bridge now provides year-round access to area hospitals,

markets, communities and schools that previously had no access during periods of rain-induced flooding. Rapid-Span Structures donated the supply, fabrication and installation of the bridge with the assistance of many generous sponsors, including Associated Engineering, with their experience with bridge designs requiring high transportability and quick installation in remote areas. This bridge will make the life of many Haitians a little safer and easier.

Rapid-Span Structures: Tamer Akkurt, P.Eng. Associated Engineering: Helen Du, P.Eng.; Jack Jiao, P.Eng.; Julien Henley, P.Eng.

Brownstock Washing Multivariable Advanced Process Control System Canfor Pulp completed the installation and commissioning of multivariable advanced process control systems on their two brownstock washing lines at their Northwood bleached kraft pulp mill in Prince George. Designed by engineers at Spartan Controls, the control system uses model predictive controllers (MPC) to optimize the washing of almost 2,000 tonnes per day of unbleached kraft pulp. Using a combination of process models, on-line solids measurements, constraint handling, and control priorities, the MPCs stabilize filtrate tank levels, weak black liquor solids, and pulp cleanliness by controlling the wash-flow rates to a pressure diffuser washer, an atmospheric diffuser washer, vacuum drum washers, decker washers, and press washers. Washing variability was reduced by a third, resulting in substantial bleaching savings, reduced soda losses, and associated economic and environmental benefits.

Slave Lake Alberta Wildfire Recovery

The Slave Lake wildfires on May 14-15, 2011 caused no fatalities but destroyed 333 equivalent single-family homes and six apartment blocks, totaling nearly 400 households. The Insurance Bureau of Canada reported that the cost of $700 million represented the second largest insured loss in Canadian history. This, coupled with $289 million in Alberta Government grant money subsequently announced, pushed the tab close to one billion dollars. Recovery has been a multifaceted and multidisciplinary project of demolition and debris removal; and providing temporary accommodation and permanent replacement of buildings and service infrastructure destroyed by fire. The ongoing effort and achievements to date have involved many engineers and engineering companies. Members of project direction team: Brian Vance, P. Eng. (Chief Administrative Officer, Town of Slave Lake) and Tom Boughner, P. Eng. (Town Recovery Manager).

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