This short submission highlights the activities of the CSCE National History Committee (NHC) since the previous update in 2020. New National and International Historic Sites have been created, specifically the Kinsol Trestle and David Thompson’s Surveying and Mapping of the Northwest of North America, respectively. Existing Historic Sites are now being regularly monitored. A major initiative has been rewriting the online descriptions of the Historic Sites using a standard template: The new descriptions together comprise roughly 55,000 words, 450 images, and 240 links to online information. Based on these new descriptions, weekly “Today in Canadian Civil Engineering History”, blurbs have appeared in the CSCE eBulletin since October 2020. The NHC is also participating in the Engineering Institute of Canada’s “Oral History Interviews to Preserve Canadian Engineering Achievements” initiative: in the summer of 2021, ten male and six female engineers were interviewed. The NHC has organized: tripartite webinars with the ASCE History and Heritage Committee and the ICE Panel on Historic Engineering Works; a special session commemorating the 80th anniversary of the construction of the Alaska Highway for the 2022 Whistler Conference; and a session on historic bridges for the 2022 Short and Medium Span Bridge Conference. Individuals interested in contributing to or participating with the CSCE National History Committee are warmly encouraged to contact the author.

The growth of structural reliability theory and applications, along with a recognition of its role in guiding the structural engineering profession in addressing some of the most important issues in design of the built environment, represents one of the key engineering achievements during the past five decades. Structural reliability provides a unifying framework for managing uncertainties affecting performance of structures and a quantitative link between the practice of structural engineering and its social consequences. Such links perhaps are most obvious in probability-based codified design and performance evaluation but there are numerous other applications, which are summarized in this special issue. As the field has matured, researchers in reliability have worked with structural engineers to elevate both the practice of structural engineering and the quality of research to levels that otherwise would not have been possible. The Joint Committee on Structural Safety has played a central role in this historic development and it will inspire future opportunities for the reliability community to build upon past successes to improve structural engineering and construction practices. This paper surveys the key theoretical developments and milestones that enable these opportunities.

The Canadian Society for Civil Engineering will designate the Kinsol Trestle near Shawnigan Lake, BC, as a National Historic Civil Engineering Site in 2022. Canadian National Railways completed this massive structure, also known as the Koksilah River Trestle, in 1920. It is noteworthy for: (1) the scale and complexity of its original design and construction; (2) the operational and engineering challenges during its long railway service life; and, (3) the innovative rehabilitation design and construction to repurpose the trestle and extend its service and heritage value on the Cowichan Valley Trail which is part of the Trans Canada Trail. Built with a seven-degree curve, it is 44 m high, 187 m long and so remains today as one of the largest and highest wooden trestle bridges in Canada, representing an enormous feat of engineering and construction. It provided rail service and contributed to development of Vancouver Island for close to 60 years—the last train crossing was in June 1979. Rehabilitation of the trestle, completed in 2011, involved the replacement of 17 of the 46 bents using all-new wood and erecting under-slung custom-built steel trusses to “bridge” between the active bents. The remaining 29 original bents are simply left in place as inactive, non-load-bearing elements. This paper briefly describes the history of this remarkable structure.

This paper presents brief histories of two iconic New Brunswick bridges: the Little Salmon River Viaduct near Grand Falls, and the Sir Hugh John Flemming Bridge at Hartland. The Little Salmon River Viaduct, the second longest in the country after the Lethbridge Viaduct, was a vital link in the National Transcontinental Railway, which became part of Canadian National Railways. R. F. Uniacke, a bridge engineer for the NTR, directed the tender design. The Dominion Bridge Company Ltd. of Lachine fabricated and erected the steel in 1910–11, with detailed design by Fred P. Shearwood, later Chief Engineer of Dominion Bridge. The Atlas Construction Company Ltd. constructed the Sir Hugh John Flemming Bridge between 1958 and 1960, based on the design of E. van Walsum, Jr., and T. J. Sluymer, Jr., of the Foundation of Canada Engineering Corporation Ltd., Montreal. It is a seven-span concrete deck arch, with a total length of 662 m.

CSA Standard A23.3:19 “Design of Concrete Structures” currently requires that the maximum yield strength, used in design calculations, be no larger than 500 MPa. The objective of the research, reported in this paper, is to determine whether the current limits for moment redistribution in continuous flexural members, Clause 9.2.4 of A23.3-19, are appropriate if High Strength Reinforcement is used. Sensitivity analyses were conducted, using SAP-2000, for two-span continuous beams with various quantities of ASTM A615/A615M Grade 100 (690 MPa) and ASTM A706 Grade 60 (420 MPa) steel reinforcement, and concrete strengths of 30 and 70 MPa. Loading cases where the live load was applied simultaneously on either both spans or on one span only were considered. Preliminary results suggest that if a full plastic collapse mechanism is present at failure, the moment redistribution percentage is independent of the grade or quantity of reinforcement. If the failure load is limited by insufficient inelastic rotation capacity at the first plastic hinge, the maximum permitted redistribution must reduce for beams with increasing mechanical reinforcement ratio, ω, values. Although the maximum permissible redistribution percentages are less for beams reinforced with Grade 100 steel than Grade 60 steel, the A23.3-19 provisions remain conservative in the cases investigated.

The Canadian Standards Association’s CSA A23.3:19 Design of Concrete Structures allows for evaluating the safety of existing structures based on analytical assessment or load testing. The latter is often favored by practitioners because the underlying concept is intuitive, so results are conclusive. The load testing procedures have the following shortcomings: (1) They do not provide insight on the actual load-carrying capacity, or how close the proof load was to the ultimate capacity of a structural component; (2) the proof load may cause irreversible structural damage, or even structural failure; and (3) many practitioners believe that a structure loaded to its nominal ultimate capacity typically engages alternate load paths to avoid failure, and that a different test result may occur under different environmental conditions. The goal of the present research is to model analytically the standard monotonic load test to assess the effectiveness of the acceptance criteria based on deflection recovery. Deficient members are represented using an effective mechanical reinforcement ratio, ω, less than the “expected” ω. Then, the total deflection of load-tested deficient members is evaluated based on a modified moment–curvature relationship that accounts for the effect of strain hardening of the reinforcing steel, and secondary and tertiary creep of concrete under high sustained loads. Residual deflections are obtained assuming the unloading is elastic. The results indicate that a limited range of deficient members can sustain the test load for 24 h without collapse, achieve a residual/total deflection ratio less than 40

The American Society of Civil Engineers and the Canadian Society for Civil Engineering have just jointly designated “David Thompson’s Surveying and Mapping of the Northwest of North America” as an International Historic Civil Engineering Landmark. David Thompson (1770–1857)—surveyor, map-maker, explorer, and fur trader for both the Hudson’s Bay and North West Companies—is considered “the greatest land geographer that the world has produced” (Tyrrell in David Thompson’s narrative of his explorations in Western America. The Champlain Society, Toronto, 1916, [13]), despite his serious visual impairment. Often accompanied by his Métis wife, Charlotte Small, he surveyed and mapped a vast region stretching from 45°N to 60°N latitude and from the western shores of Hudson Bay to the Pacific Ocean between 1790 and 1812. His 1814 Great Map, compiled from his surveys and those of Alexander Mackenzie, Simon Fraser, George Vancouver and his teacher Philip Turnor, laid the groundwork for development of the Northwest of North America. This paper briefly describes Thompson’s life and remarkable achievements.

The Britannia Mine, situated on the east shore of Howe Sound, 45 km (28 miles) north of Vancouver, produced more copper than any other mine in the British Empire between 1925 and 1930. Dr. A. A. Forbes originally discovered minerals there in 1888. When it ceased operations in 1974, it had produced over 517,000 metric tonnes (mt) of copper, 125,000 mt of zinc, and significant quantities of lead, cadmium, silver, gold and pyrite. The mine applied and improved a froth-flotation system that was particularly efficient in separating and concentrating the ore: the Britannia deep-cell flotation system helped triple the yield at one of their mills. The steep local mountain slopes were used to generate hydroelectric power that provided compressed air for the mine ventilation system, and to transport ore through the concentrator by gravity. Old rails were recycled to make grinding balls for the mills, many years before recycling technology and the circular economy were recognized to be desirable practices. They used IBM punch cards for time keeping in 1929. The mine also leaves an environmental legacy, however, as one of the largest sources of metal pollution in North America. Remediation efforts to protect Howe Sound and the Squamish River from acid rock drainage will be necessary for the foreseeable future.

The Pattullo Bridge over the Fraser River is the only major steel through-arch highway bridge remaining in British Columbia. Opened in 1937, the bridge replaced the narrow traffic lane above the railway tracks on the New Westminster Rail Bridge, improving vehicular traffic volumes. It connects the former BC capital of New Westminster with the region of Surrey and, along the Pacific Highway, the USA. Col. W. G. Swan (1885–1970) led the bridge design team, and the structural steel was fabricated and erected by the Dominion Bridge Company, both iconic names in the history of bridge engineering in BC. The Pattullo Bridge was the first major crossing into the Southern Greater Vancouver Area during a time of rapid societal expansion and has served a pivotal role, for almost 90 years, connecting suburban areas with metropolitan Vancouver. The impending replacement of the Pattullo Bridge heightens its historic importance: steel through-arch designs in BC, and so a part of British Columbia’s structural engineering history will become extinct.

1929 Born in England 1951 Honours B.Sc. (Eng.), University of Nottingham 1954 Ph.D., University of Nottingham 1954 Immigrates to Canada to work at Ontario Department of Highways Bridge Office, Toronto 1956 Joins P.L. Pratley’s consulting firm, Montreal 1965 Wins competition to design pedestrian bridges for Expo 67 world fair 1965–72 Partner, Pratley and Dorton, Consulting Engineers, Montreal 1972–75 Structures Research Group Engineer, Ontario Ministry of Transportation (MTO), Toronto 1974–79 Chair, American Concrete Institute Committee 358, Concrete Guideways 1976–92Manager, MTOBridgeDesign Office 1977 Awarded Canadian Society for Civil Engineering (CSCE) Casimir Gzowski Medal 1982 Chair, Organizing Committee for Inaugural International Conference on Short and Medium Span Bridges 1982 Awarded Fellowship of CSCE 1984 Awarded James A. Vance Award 1984 Chair, International Scientific Committee for IABSE Vancouver Congress 1984 Awarded Honorary Membership of IABSE 1986–89 Editor, Canadian Journal of Civil Engineering 1988 Awarded CSCE A.B. Sanderson Award 1988 Awarded Engineering Institute of Canada Julian C. Smith Medal 1988 Proposed CSCE P.L. Pratley Award for best paper on bridge engineering 1989 Awarded Honorary Doctorate, University of Waterloo, Canada 1990 Awarded Fellowship of Engineering Institute of Canada 1990 Awarded Honorary Doctorate, Queen’s University at Kingston, Ontario 1991 Chair, International Scientific Committee of IABSE Leningrad Symposium 1993–99 Manager, Ontario Office of Buckland and Taylor Ltd. 1993 Awarded Fellowship in Canadian Academy of Engineering 1993–99 Vice President, IABSE 2002 Awarded CSCE Lifetime Achievement Award 2005 Invested as Member of the Order of Canada, Canada’s highest civilian honour. 2012 Awarded Queen Elizabeth II Diamond Jubilee Medal 2016 Published Spanning the Years: Recollections of Six Decades in Bridge Engineering 2019 Awarded CSCE Gordon Plewes Award 2020 Passes away in Toronto, Canada

Integral abutment bridges eliminate expansion joints by integrating the bridge superstructure with the abutments. The thermally induced movements of the superstructure are accommodated by flexural deformations of the supporting piles. Extensive numerical analyses have been conducted to clarify the structural response and soil-structure interactions. This paper comprises a comprehensive review of the development of structural modelling techniques and the assumptions embedded in numerical modelling. The review indicates that validation of the numerical models is necessary. The typical approach for validation is to compare the analytical results with data collected from on-site measurements, which are normally expensive, time-consuming and difficult to control. The geotechnical centrifuge modelling technique is proposed as an alternative for model validation.

This paper presents preliminary findings of a study of the flexural ductility of beams reinforced with ASTM A615 Grades 60 and 100, A706 Grades 60 and 80, or A1035 Grade 100 longitudinal steel bars. Moment–curvature relationships were generated for beams with reinforcement ratios varying between 0.3 and 1.5% with concrete compressive strengths between 30 and 90 MPa. Curvature ductility factors were computed. Regression analysis techniques were used to assess whether the ductility corresponding to a given mechanical reinforcement ratio were significantly different for the different steel grades. It is concluded that the curvature ductility factor is, in all cases investigated, essentially proportional to the inverse of the mechanical reinforcement ratio. The ductility factors for ASTM A615 Grade 100 reinforcement are markedly less than those for the other grades, suggesting that a more stringent target reliability index should be used to calibrate the resistance factor for ASTM A615 Grade 100 reinforcement.

The Middle Road Bridge, constructed in 1909 on present-day Sherway Drive to span Etobicoke Creek between Toronto and Mississauga, was recognized as a CSCE Civil Engineering Historic Site in 2009. The official CSCE plaque for this structure will be unveiled at the 2021 Annual Conference and subsequently installed on site. The Toronto firm Barber & Young designed the bridge, the first reinforced-concrete tied-arch-truss (or “rainbow”) bridge built in North America. The paper describes some of the design and construction innovations in the structure and the professional lives of James Franklin Barber (1875–1945) and Clarence Richard Young (1869–1964), who left the partnership in 1911 to become Professor of Civil Engineering at the University of Toronto and, subsequently, Dean of the Faculty of Applied Science and Engineering from 1941 to 1949.

Military vehicles are sometimes required to transit bridges owned and operated by civilian bridge authorities. Using available data regarding the gross vehicle weight and associated axle loads of military traffic, live load factors, calibrated to the Canadian Highway Bridge Design Code, are proposed for bridge design and evaluation. This paper recommends live load factors for three categories of military vehicles: (i) wheeled-transport vehicles; (ii) wheeled-fighting vehicles; and (iii) tracked-fighting vehicles. The values are derived for interior girders of simply supported slab-on-girder bridges subjected to a single lane of traffic loading and are believed to be generally applicable for other structural elements and bridge types. Inherent differences between fighting vehicles, which are heavily armoured, and transport vehicles, which although armoured have high payloads, suggest that highway bridges should be evaluated separately for military fighting vehicles and military transport vehicles using distinct live load factors.

Concrete overlays are widely used to rehabilitate bridge decks. This investigation presents parametric and sensitivity analyses of the mechanical strains due to restraint of shrinkage of the overlay that may cause it to crack. The parametric analysis identifies the significant variables and the sensitivity analysis quantifies the correlations between these variables and the magnitude of mechanical strains. The strain analysis accounts for drying shrinkage using Fick's law, and for tensile creep strains. Total strains are computed by superposition, assuming a linear-elastic concrete behavior, using a time-history approach developed in a previous investigation. Concrete overlays on concrete slabs and composite systems are considered. Compressive strength of the overlay concrete, curing period, overlay thickness and environmental humidity contribute the most to the variability of the analytically predicted mechanical strains.

The target reliability index for the assessment of an existing flexural element depends on the warning of failure provided and therefore on the total deflection at incipient failure. Sensitivity analyses accounting for both the linear-elastic-cracked and plastic responses indicate that the warning of failure depends on the ductility of critical cross sections (and therefore on the flexural reinforcement ratio) and the length of the plastic hinge regions (and therefore on the applied load configuration). Structural redundancy typically reduces the total deflection at incipient member failure and therefore is an inconsistent indicator of warning of failure. The deflections at incipient failure can be normalized as fractions of the span length to quantify the Warning Factor, W, as a function of the reinforcement ratio, span length, and effective beam depth. This continuous variable can replace existing discretized values of the Warning Factor based on somewhat subjective classifications of ductility and redundancy.

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Proof load tests have the potential to confirm the structural safety of a component suspected of being substandard. Methodologies are available to revise the reliability index of the suspect component, after it passes a proof load test, that essentially assume that the probability that the actual resistance is less than the proof load is zero. There is some sense among practitioners, however, that “you can always pass a proof load test” and so the current methodologies for updating the reliability index may be unconservative. This paper presents the development of rational criteria for including proof load testing into the safety assessment that account for imperfect repeatability of the test result. The necessary mathematical formulation requires the following steps: 1. Define the likelihood that a particular proof load test can be successfully repeated, i.e., (100-α)%; 2. Partially truncate the lower tail of the resistance distribution such that the cumulative probability corresponding to the load test magnitude equals the probability that the load test will not be successfully repeated, i.e., α%; and, 3. Carry out reliability analyses using the partially truncated resistance distribution. Preliminary findings are presented assuming the load and original resistance distributions are normal. Two example calculations demonstrate the applicability of the method, and indicate ist potential value in determining the necessary test load magnitude to achieve a desired reliability index.

The design and modelling of 10-, 15-, and 20-storey wood buildings with cross-laminated timber and glulam structural members are presented in the present study. The system is platform-type construction with a cross-laminated timber core, perimeter walls as lateral load resisting system, and glulam columns as the gravity system. The designed buildings satisfy requirements stipulated in applicable design codes in Canada. The hysteretic models and the associated parameters used to model the fasteners for wood members are developed. Assessments of the nonlinear inelastic seismic responses and capacity curves of the designed buildings are carried out using the incremental dynamic analysis (IDA) and nonlinear static pushover analysis (NSPA) methods. The results indicate that the NSPA curve closely approximates the mean capacity curve estimated using the IDA curves for wood buildings. The post-yield stiffness ratio to initial stiffness for the wood buildings ranges from approximately 0.35 to 0.55. The results also show that the effect of the record-to-record variability on the IDA curves is substantial.

Military vehicles frequently use civilian bridges. The loading effects of military vehicles, both wheeled and tracked, are specific and different than those of civilian vehicles in normal traffic. Calibration to determine appropriate load factors for military loading of civilian bridges has not been fully performed and the corresponding levels of safety have not been quantified. This is partially due to the lack of probabilistic information of the gross vehicle weights and corresponding axle loads of military vehicles while operating in real-world conditions. This paper quantifies probabilistically the gross vehicle weight and axle loads for three military vehicles in use by NATO, each of which is representative of: military transport vehicles; armoured personnel carriers; and main battle tanks. A general means are proposed to quantify the probabilistic gross vehicle weight of military vehicles on the basis of maximum nominal payload as a proportion of the total nominal vehicle weight. Based on observed probabilistic gross vehicle weight of military vehicles, it is recommended to differentiate between military transport and military fighting vehicles as different categories of vehicles in bridge evaluation.