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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Excavation and support of underground excavations beneath Canada's Historic Library of Parliament Building, Ottawa

The Library of Parliament in the City of Ottawa in Canada dominates the Quebec side of Parliament Hill. Originally constructed in the 1860s and extensively rebuilt in 1953, the Library remains as one of three original buildings on the Hill. As existing space on Parliament Hill is at a premium and heritage and sensitive historic, visual and environmental requirements necessitated that all existing structures would remain visually unaltered, measures had to be taken to develop underground space in order to provide much needed upgrading of mechanical, electrical, heating and ventilation services to standards appropriate for preservation of the Library's collections. Precedent had been set two years previously in construction of the Centre Block Underground Services Building by deep excavation into the rock mass beneath the perimeter and main chamber of the House of Commons that, with careful excavation and a comprehensive program of sequenced rock support installation, excavation could be undertaken in close proximity or even under the actual building structures. For the Library the key challenge was being able to develop sufficient underground space without compromising the stability of the fragile masonry building structure. Achieving this has required detailed design of complex excavation geometries and implementation of stringent control procedures to ensure that the required quality of excavations was achieved. Optimization studies lead to development of a concept involving excavation of an 8 m deep, 20 m diameter excavation, concentrically located directly beneath the core of the structure with associated cross tunnels, stairs, and an elevator, together with angled raise bores to facilitate the necessary services. Design of the excavations and of the monitoring arrays of instrumentation and detailed supervision of the excavation works has been key to ensuring minimal disturbance to the existing building by (i) requiring extremely high standards of perimeter excavation control and (ii) pre-supporting all load-bearing areas of the existing bedrock foundations adjacent to the excavations. Control of excavation sequencing and monitoring of movement behaviour of both the rock and the foundation zones of the structure have allowed control to be maintained of building and rockmass performance. This has been achieved by comparing as-observed movement trends with inferences derived from evaluation of the comprehensive output generated from detailed 2D and 3D numerical modelling undertaken during the detailed design stage. This paper describes the concept assessment, the design development and support detailing, outlines the instrumentation installations developed at the design stage and implemented during construction and then presents some of the data from the excavation response behaviour of the rock mass and structure to the excavation works undertaken within and adjacent to the building. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.

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  • Authors:
    • FRAME, P
    • CARTER, T G
    • GRAAF, P J
    • TELESNICKI, M J
    • MILLER, D W
    • WEBB, P S
    • POULTER, L
  • Publication Date: 2004-7

Language

  • English

Media Info

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Filing Info

  • Accession Number: 01011553
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Dec 19 2005 3:17PM