Implementation of Foundation Repairs to Improve the Operational Life of Existing Coker Structures

Charles L. Lee, David J. Walter, Parm Parmar

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Earth Walls and Foundations

ABSTRACT: ation of Foundation Repairs to Improve the Operational Life of Existing Coker Structures Charles L. Lee Edmonton, Alberta, Canada David J. Walter AMEC Environment & Infrastructure, Edmonton, Alberta, Canada Parm Parmar Suncor Energy Inc., Calgary, Alberta, Canada ABSTRACT top of a nearly vertical limestone face that separates the cokers from the adjacent coke pit. The limestone face is supported by a concrete wall along the discharge side of the 8 coker structures. The concrete coke pit wall was embedded into limestone at its base, was held against the near vertical limestone face using short rock anchors, and was anchored into the mat foundations near the top of the wall using steel tie-rods. During the +45 years over which the cokers had been in operation, the stability and bearing resistance of the structure had degraded due to a combination of weathering of limestone, corrosion of anchors and tie rods, and damage to the concrete face of the coke pit wall from coke removal operations. This paper provides details on the design and remediation performed at the coke pit wall during a 30 day shutdown window. RÉSUMÉ Huit structures de coker construit au cours de la fin des années 1960 et début des années 1970 sont pris en charge sur les fondations matelas portant sur le dessus un visage presque verticales de calcaire qui sépare les cokers de la fosse de coke adjacents. Le visage de calcaire est soutenu par un mur de béton le long du côté de la décharge des 8 structures coker. Le mur des stands béton coke a été incorporé dans le calcaire à sa base, a eu lieu contre le calcaire vertical près face à l'aide d'ancres de roche court et était ancré dans les fondations matelas vers le haut du mur à l'aide de tiges en acier. Pendant les années de + 45 sur lesquels les cokers avaient été en opération, la stabilité et portant la résistance de la structure étaient dégradé en raison d'une combinaison de l'altération du calcaire, la corrosion des ancrages et tirants et chocs dus à la face de béton du mur des stands de la coke à opérations de déneigement de coke. Cet article fournit des détails sur la conception et la remise en état effectués sur le mur des stands coke pendant une fenêtre d'arrêt de 30 jours. 1 INTRODUCTION At an operational oil sands processing plant site in the Fort McMurray, AB region, eight (8) coker structures are supported by mat foundations at the crest of a near vertical limestone face that is supported by a concrete coke pit wall. The native limestone behind the coke pit wall and the wall itself experienced weathering and deterioration over the +45 year time period since the original construction. This deterioration has resulted in the structure having reduced overall stability and bearing resistance, and uncertainties relative to structural integrity of various wall components. As it was the intent of the Owner to undertake repairs to the coker drums themselves to extend the operational life of the facility, it was also necessary to undertake measures to ensure adequate stability and integrity of the coke pit wall and coker foundations for the proposed extended lifespan of the structure. To extend the operational life of the structure and improve the stability of the structure, remedial measures were implemented to the structure in April and May 2013 during an operational shutdown window. During a 30 day shutdown window, remedial measures consisting of infilling of voids behind the original wall, placement of new cast-in-place concrete wall panels in front of the original wall, and installation of post-tensioned rock anchors through the new wall panels were implemented. This paper provides a summary of the condition of the structure prior to remediation, the engineered solution, and details regarding the implementation of the remedial measures. 2 COKER STRUCTURES DESIGN DETAILS The Coker structures were s on reinforced concrete mat foundations cast on an excavated limestone bench at Elev. 251.8 m (826 ft). The back corners of the mat foundations were anchored into the underlying limestone using inclined non-corrosion protected grouted anchors. The superstructure of the Cokers was supported on the mat foundations. In front of the mat foundations, the limestone surface was excavated at a near vertical slope to the coke pit floor located at approximately Elev. 239.9 m (787 ft). Some blocks of fractured limestone present below the mat foundation were tied into the underlying more competent limestone using short grouted rock anchor bolts. The coke pit wall was constructed by placing pre-cast concrete wall panels at an inclination of 15 degrees from

RÉSUMÉ: ementation of Foundation Repairs to Improve the Operational Life of Existing Coker Structures Charles L. Lee Edmonton, Alberta, Canada David J. Walter AMEC Environment & Infrastructure, Edmonton, Alberta, Canada Parm Parmar Suncor Energy Inc., Calgary, Alberta, Canada ABSTRACT

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Cite this article:
Charles L. Lee; David J. Walter; Parm Parmar (2014) Implementation of Foundation Repairs to Improve the Operational Life of Existing Coker Structures in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper170,author = Charles L. Lee; David J. Walter; Parm Parmar,title = Implementation of Foundation Repairs to Improve the Operational Life of Existing Coker Structures ,year = 2014}