The Orangutan Outdoor Exhibit project focuses on providing two (2) new outdoor habitats, with improvement to the existing indoor habitat, to add vast climbing opportunities to improve the living conditions for the Toronto Zoo orangutans.
The new outdoor exhibits include high mast poles soaring 13m in the air to support climbing cables for the orangutans which will span across publicly accessible boardwalks and viewing platforms. The public access spaces will overlook a naturalized outdoor habitat complete with streams, hills, and rock faces to allow the orangutans to interact in a more natural environment similar to their native forest habitats.
GEI Consultants has been retained by Midome to complete the design of the geostructural components of the project including the design-build deep foundation micropile and caisson elements for the high mast poles, permanent support of excavation shoring to support architectural rock form shotcrete, and slope stability assessment within regulated ravine areas.
The challenging deep foundation design integrated micropile designs to accommodate the access restrictions to the high mast pole locations. Compounding the design challenges was balancing the foundation stiffness requirements between the high mast poles, which were supported on varying types of deep foundations. Due to the distance between poles ranging up to 50m, foundation stiffness and deflection were critical design criteria elements to manage load transfer and cable deflections between high mast poles.
Interesting elements included the permanent shoring support of excavation that had to consider permanent architectural shotcrete facing to provide a rock-form finish look for naturalized aesthetics of the orangutan habitat. The shoring was designed to project to varying elevations above the proposed design grade to support the shotcrete rock-forms.
Multiple stakeholders were involved with the project’s approvals, including the Toronto and Region Conservation Authority (TRCA) which required supplemental advanced geotechnical field investigation and detailed slope stability analysis at the foundations to the high mast poles. The slope stability assessment had to consider long-term slope stability and also the effect on the high mast pole deep foundation micropile elements so that the designs would accommodate lateral and erosion forces, plus maintain the tower support in the event of a slope failure.
GEI prepared the supplemental slope stability and was Engineer of Record for the slope stability and high mast pole deep foundation elements, which included coordination with agency stakeholders for project critical approvals.