IMPLEMENTATION OF FOUNDATION REPAIRS TO IMPROVE THE OPERATIONAL LIFE
OF EXISTING COKER STRUCTURES
Charles L. Lee, P.Eng.
AMEC Environment & Infrastructure, Edmonton, Alberta, Canada
David J Walter, Ph.D, P.Eng
AMEC Environment & Infrastructure, Edmonton, Alberta, Canada
Parm Parmar, P.Eng.
Suncor Energy Inc.
ABSTRACT
Eight coker structures constructed during the late 1960’s and early 1970’s are supported on mat
foundations bearing on limestone at the top of a 90 m (300 ft) long by 12.2 m (40 ft) high
concrete wall that separates the mat foundations from the adjacent coke pit. 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 have been in operation, the
stability and bearing resistance of the structure have been impacted by a combination of
weathering of limestone behind the coke pit wall, corrosion of anchors and tie rods, and
operational damage to the concrete face of the coke pit wall. In addition to other measures that
were being implemented by the owner to extend the operational life of the coker structures, it
was necessary to implement repairs and improvements to the coke pit wall to provide adequate
long term stability and bearing resistance of the structure.
Various options were considered for improving the long term stability and bearing resistance of
the coker structures. Major criteria that governed the choice of a design solution included a
need to provide minimal disruption to long-term operations of the cokers and the coke pit, and a
requirement that any necessary repairs be completed during a scheduled 30 day shutdown
window. The option that was ultimately chosen for construction was a replacement wall to be
built in front of the existing coke pit wall, with the wall supported using rock anchors extending
through the concrete wall and into competent limestone below the coker structures. The initial
phase of the remedial measures was successfully implemented during a 30 day shutdown in
April-May 2013. During this shutdown period, 25 pre-fabricated 3.6 m by 9.1 m concrete wall
panels were placed in front of the upper portions of the original concrete coke pit wall and each
wall panel was supported by 3 – 1070 kN rock anchors extending into limestone. Construction
of remedial measures for the lower portion of the coke pit wall is scheduled for another planned
shutdown period during 2018.