DESIGN AND ANALYSIS CHALLENGES IN APPLYING SEISMIC ISOLATION TO THE CANADIAN PARLIAMENT BUILDING
Bibliographic record
Abstract
The seismic upgrade of Canada’s iconic heritage Parliament Building in Ottawa, known as the Centre Block and Peace Tower, will include the installation of a seismic isolation system within the basement of the Centre Block and beneath the Peace Tower, and when complete will be one of the largest seismically-isolated heritage buildings in North America. Similar to that required by the National Building Code of Canada for new buildings, a three-dimensional non-linear dynamic analysis was performed to establish the satisfactory performance of the seismic isolation system design. The isolation system will comprise approximately 580 isolation bearings, consisting of a range of sizes of natural rubber bearings, lead-rubber bearings and flat sliding bearings. The walls and floors were modelled using finite element shell objects. Beam and columns were modelled with frame elements. Reduced element stiffness to account for cracking of the concrete and masonry sections was incorporated through use of element stiffness modifiers - determined from nonlinear studies of individual walls sections. The isolation system components were modelled using nonlinear hysteretic elements and friction sliding elements. The fundamental periods predicted by the model were validated by ambient vibration tests of the Centre Block and Peace Tower. Two suites of 11 time history ground motions, compatible with the short-period and long-period parts of the Uniform Hazard Spectrum, were assessed, including project specific vertical ground motion components. An estimate of the potential range of the Centre Block’s dynamic response was obtained using upper and lower bound material and isolator properties. Unique to this project is the target mean base shear of 3% of the seismic weight for this building located in a region of low to moderate seismic hazard. This paper will provide an overview of the challenges involved in developing the seismic isolation system design, and describe the complex finite element modelling and detailed analyses that have been undertaken. Also discussed are considerations for isolated buildings located in cold climates such as Ottawa, where the effects of snow build-up around the perimeter of the building and ice adhesion at exposed sliding surfaces of the moat covers can adversely contribute to the breakaway resistance of the isolation system. A variety of effective mitigation measures and details to minimize additional breakaway resistance are outlined.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".