2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference

Central LRT Rehabilitation in Edmonton, Alberta

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Mr. Mark Scanlon, Arrow Engineering Inc (Presenter)

Opened in 1978, the station structure, located directly underneath Jasper Avenue, Edmonton’s major artery, consists of precast pre-stressed concrete cross beams supported by L-beam edge girders. The structure has been leaking from the road surface and vulnerable to decades of chloride attack from the road salts used during prolonged winter road clearing operations. A study performed in 2008 found that the two major concrete L-beam support girders, spanning over 200 m each, supported by a series of concrete piles, were corroded at the bearing seat. The pre-stressed concrete beams which the girders were supporting, and which were ultimately supporting the roadway, were found to have been affected to a lesser extent and were rehabilitated using CFRP wrap. The corroded bearing seat of the L-beam was relieved of the load from the pre-stressed concrete beams by transferring  the load directly to the piles using steel support members installed where such measures were feasible. Shear friction reinforcement was used to transfer the load directly from the cross-beams to the areas of concrete L-beam that were unaffected by chloride attack and where steel columns were not practical to install.

The rehabilitation of Edmonton’s Central Light Rapid Transit (LRT) Station required the use of adaptive design approaches to overcome substantial existing spacial restrictions, co-ordination to ensure that a multi-disciplined team approach was ultimately successful and that the station could maintain full functionality during construction. A sustainable approach to the design was implemented to ensure that the work completed would help sustain Edmonton’s infrastructure for the next 75 to 100 years.