Instrumentation & Performance of Tied-Back Shotcrete Shoring in Sand Adjacent to a Hospital Structure

Carol Domitric & Matthew Janes

Recent additions to the Brantford General Hospital expansion included construction of a new hospital wing, involving excavations of up to 11 metres (36 feet) depth, in loose to compact sand adjacent to an existing eight-storey hospital structure. The tendered contract called for interlocking caisson walls. An alternative method of temporary excavation support, tied-back shotcrete shoring, was proposed by the Isherwood/HC Matcon Ltd. design-build team. View PDF.

Soil Nailing Earth Shoring System – A Ten-Year Update

Nadir Ansari & Carol Domitric 

In the past forty years, one of the major trends in earth retaining structure design has been towards reinforcement methods which improve the internal strengths of soil masses sufficiently to make them self supporting. These methods include the New Austrian Tunneling Method (NATM), Reinforced Earth, and Soil Nailing. View PDF. 

St. Clair River Rail Tunnel, Sarnia Design – Design and Construction of a Shaft for the TBM Cutterhead Retrieval

Brian Isherwood, Nadir Ansari & Peter McDonald

The planning, design, and construction of the new St. Clair River Tunnel has been described in several previous papers with some mention of the unplanned Retrieval Shaft which was necessary to remove and service the Cutterhead of the Tunnel Boring Machine before it passed under the St. Clair River. This paper describes the design and construction of the shaft and touches on the difficulties and risks involved with crash-programme rescue operation. View PDF. 

The Bow, EnCana: Design, Monitoring, and Results of a Deep Excavation in Downtown Calgary

Matthew Janes & Thomas Lardner 

The Bow office complex will become the new headquarters of EnCana Corporation, a leading Canadian oil and gas company. The shoring system, encompassing nearly two city blocks to a depth of 20.5 m was required to support the surrounding utilities and buildings in downtown Calgary. Past excavations in the area experienced large amounts of rock movement, whose mechanics were poorly understood. The focus of this paper is the design process and construction results concerning rock movement and the effectiveness of the shoring structure. View PDF. 

Numerical Analyses on the Wall Deflections of The Bow Excavation

Quangfeng Qu, KwanYee Lo, Matthew Janes, Silvana Micic & Thomas Lardner

The construction of The Bow office tower involved an excavation approximately 100 m wide, 190 m long, and 21 m below ground surface. This paper presents a finite element analysis of stress and displacement caused by the excavation, and then evaluates the influence of the shear band and the weak zone in rock by comparing the measured performance of the shoring system with the calculated. View PDF. 

Innovations and Challenges During Urban Development – Shoring and Foundations of Canada’s Tallest Residential Building

Shawna Munn, Nadir Ansari & Toben Jerry

With ever increasing demands on space in urban environments and smaller available footprints, buildings are being designed to increasing heights to meet the need. The One, Canada’s tallest residential building under construction, will stand at 85 storeys and is located at one of the most prominent and built up intersections in Toronto, Yonge Street and Bloor Street. This case history describes the shoring design option evaluation, performance, and lessons learned to date throughout construction of the building foundations within a small, congested site. View PDF. 

Prescriptive Specification Design: The Impact on Cost and Constructability – Case History

Shawna Munn, Allison Bennett & Nadir Ansari

This paper outlines how specification driven design has made Toronto Area transit infrastructure projects more expensive than similar private projects, and provides a case study of the results of an excavation at Launch Shaft 1 (LS1) for the Eglinton Crosstown Light Rail Transit project in Toronto, Ontario. The paper will describe the impact specification driven design parameters can have on design economy, constructability, and schedule and will suggest an alternative approach utilizing the Observational Method. View PDF. 

Design Recommendations for Fiberglass Reinforced Tunnel Softeyes

Shawna Munn, Jakub Hudler & Matthew Alexander

This paper outlines the design challenges and recommendations for use of fibreglass reinforcement in tunnel headwall softeyes as learned through transit construction projects in the Greater Toronto Area (GTA). View PDF. 

Tunnel Headwall Softeyes: Fiberglass Design Applications and Constructabililty Challenges

Shawna Munn & Jakub Hudler

This paper outlines the use of tunneling headwall softeyes for transit construction projects in the Greater Toronto Area (GTA) over the past decade. View PDF. 

Heritage Façade Support and Excavation Shoring – A Micropile Case History

Amanda Gordon, Michael Sousa, & Brian Isherwood

This paper outlines the design challenges and ultimate approach to supporting two street facing façades of the six-storey Canadian Westinghouse Building, a heritage building in Toronto’s Entertainment District, while the remainder was demolished to make way for development, including two towers and five underground parking levels. View PDF.

Hybrid Shoring Solutions for a Challenging Excavation Project Adjacent to a Subway – 21 Avenue Road, Toronto

Thomas Fiala & Graeme Smart

This paper presents the unique, non-conventional hybrid shoring solution Isherwood developed to address the challenges at Yorkville Plaza II, a 40-storey signature condominium residence with six levels of underground parking, as well as other complications that surfaced during the project: non-encroachment requirements (no tiebacks) beneath uncooperative neighbours, tight geometry to install shoring, and Toronto’s two coldest winters in decades. View PDF.

Performance based excavation support design for challenging urban site geometry in Toronto, Canada

Erika Acton, Shawna Munn, Carol Domitric

This paper covers two major challenges encountered when designing and constructing the EQ Bank Tower in Toronto, which included an 18m deep excavation surrounded by a historical façade. The innovative and adaptable solutions carried out using performance-based design leveraging the observational method include installation of a shoring system in a 500mm gap between the historical façade and a live gas main as well as excavating 10m into expansive shale bedrock adjacent to a sensitive neighbouring building. View PDF.