Canadian Council of Professional Engineers

A very high dose rate of ionizing radiation (> 40 Gy s -1 , "FLASH" radiation) causes less damage to healthy cells than moderate dose rates. Following a nuclear explosion, a significant fraction of the radiation dose is delivered at this rate. Consequently, there is a potential impact on the radiation risk estimates currently in use, which are largely based on the studies of the populations of Hiroshima and Nagasaki. Based on the scientific literature covering the relevant dose range, we estimate the maximum protective effect on genetic damage is about a factor 0.6 (-40%). Using this number and the relevant dosimetry for the Life Span Study population, while excluding data doses above 4 Gy, the maximum magnitude of the effect for Hiroshima would be somewhere between 3.3% and 13.1%, depending on the dose received. These values are sensitive to the neutron relative biological effectiveness (RBE), which was assumed to be 10 in the nominal case. In Nagasaki, the magnitude varies little with the dose, between 7.3% and 9.3%, and is relatively insensitive to the neutron RBE. Nevertheless, there are some indications that a threshold for this effect around 1 Gy may be observed in biodosimetric studies of this population. Still, due to the high heterogeneity in the relevant experimental data, further research should be carried out to investigate the FLASH effect at doses relevant to epidemiology (between 0.1 to 4 Gy) instead of the higher doses used in radiotherapy, for which most research on FLASH effect is carried out.

Loadbearing, concrete masonry walls are an effective structural system to resist combined out-of-plane and gravity loads. A large portion of the market for these walls is composed of single-story warehouse and industry buildings, and public-use structures such as theaters, community centers, and school gymnasiums. In these applications, it is common to have tall walls with an effective height-to-thickness ratio greater than 30. North American masonry design standards (CSA S304-14 and TMS 402-16) have special design requirements for these types of masonry walls due to their perceived vulnerability to second-order effects. In particular, one of the CSA S304-14 requirements consists of assuming a pinned base condition to calculate design moments and deflections, which severely impacts the available strength and stiffness of tall masonry walls. The objective of this study is to assess the influence of the rotational base stiffness on the out-of-plane response of slender masonry walls subjected to cyclic loading, in terms of strength, stiffness, base damage, and failure modes. Two full-scale, partially grouted slender masonry walls were tested under combined eccentric axial load and cyclic lateral out-of-plane pressure. The tests showed increased flexural capacity and decreased deflections in the out-of-plane direction when rotational stiffness at the base is accounted for, with limited degradation at the wall base observed during cyclic loading. Results suggest that accounting for the presence of the base stiffness provides additional strength to the wall that may lead to more economical masonry wall designs while maintaining satisfactory strength and reliable structural performance.

Abstract This study presents a semi-analytical approach to solve the Laplace equation in arbitrarily shaped two-dimensional domains. The method is meshless and addresses boundary value problems that include both pure Dirichlet and mixed Dirichlet-Neumann boundary conditions. The solution is obtained via a weighted superposition of harmonic polynomials which are obtained via an orthonormalization approach. We show that the approach is efficient in terms of number of operations. The numerical solution is convergent and exact (within machine precision) given a sufficient number of terms in the series. Moreover, the method offers several advantages over traditional approaches. Advantages include providing analytical expressions for the stream function and velocity components when solving potential flow problems. There are also important implications for the storage of model results; the method offers extremely low cost data storage. In the paper, several example applications involving arbitrary domains are presented. The results obtained are compared with known analytical solutions.

Water distribution networks (WDNs) are complex interconnected networks that require extensive planning and maintenance to ensure good quality water is delivered to all consumers. The main task of WDNs is to provide consumers with a minimum acceptable level of supply (in terms of pressure, availability, and water quality) at all times under a range of operating conditions. However, the water infrastructure in North America signifies an urgent need of upgrading the aging and deteriorating distribution systems if they are to continue to provide consumers with reliable and safe water supplies. In this context, this research is proposing a new reliability model for assessing the mechanical/structural as well as hydraulic conditions of a WDN to identify failure-prone components and prioritize their renewal. The developed model provides a systematic and practical methodology to calculate the mechanical/structural reliability of the pipe and its accessories (valves, hydrants, and so on) through the consideration of historical failures of components. The research deployed pressure-dependent demand analysis to determine the hydraulic reliability of the network in meeting the pressure requirements and overall hydraulics of the network. The minimum-cut-set theory was implemented in both reliability assessments, and the outputs of the two models were integrated to provide a representative reliability of the network. A sensitivity analysis was followed to study the change in segments’ attributes on the mechanical/structural and hydraulic reliabilities. The approach was implemented on the City of London, Canada, network (north and south) to test its applicability. The developed model is expected to assist decision makers in integrating the failure records with the hydraulic simulation to plan for optimum intervention actions.

Abstract NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract Main Menu Non-Academic Instruction: As part of their engineering design content Canadian universities make strong use of projects solicited from and put forward by private sector, often involving the submitting firms in both advisory and evaluation roles. This seems to acknowledge the need for “real life” projects as a break from the strictly academic, theoretical framework and the involvement of non-academic engineers to provide the “applications” perspective. It also often provides students with valuable experience in presenting their cases outside the classroom environment. Such experience often provides the only exposure to such things as codes and their requirements, assessments of loadings for which there are no handbooks and the realities of limited budgets and project phasing, that students get. Given the earlier mentioned link between accreditation and the constituent members, the question arises as to whether the accreditation criteria should be amended to embed this practice. While Canadian criteria already stipulate that engineering science and engineering design content be taught by “P.Eng’s” (licensed engineers), the focus intended has been on the academic faculty. Should some portion of an accredited program be reserved for presentation by non- academic members of the profession or does this encroach on the universities’ freedoms or further still, is it moving some of the internship phase inappropriately back into the academic formation? Conclusion While the foregoing considerations are all raised in the Canadian context, each in its own way also has implications in the global sense, particularly as engineers are increasingly mobile. The challenge for the CEAB will continue to be to facilitate innovation within universities, while remaining fully mindful of the “public interest” expectations.

Abstract Located 500 km north of the Arctic Circle, the massive Mary River Iron mine project required an operating ore dock to annually ship 3.5 million tonnes of iron ore to world markets. The high latitude Arctic ore dock loaded its first bulk carrier on August 8, 2015 from the its record breaking −17.75 m deep water berth. The project was executed by a design-build team selected by the owner after it became apparent the traditional design-bid-build method could not achieve schedule and budget objectives. Major challenges facing the design-build team included −35 degree celcius temperatures, 24- hour darkness, remote logistics, compressed schedule and varying geotechnical site conditions. To minimize risk in this challenging environment, the design-build team redesigned most of the project with a major focus on modularization of components in the south and utilization of a land-based construction methods rather than reliance on a fleet of marine equipment.

Abstract A comprehensive laboratory evaluation of the geotechnical and geoenvironmental properties of five predominant types of construction and demolition (C&D) waste materials was undertaken in th...

A high-speed railway project for trains of speeds of up to 160 km/h is currently being constructed between Rawang and Bidor (110 km long) in Peninsular Malaysia. The ground improvement methods adopted in the project are vibro-replacement with stone columns, dry deep soil mixing (cement columns), geogrid-reinforced piled embankments with individual pile caps and removal/replacement works. This paper provides a detailed insight into the design and implementation of vibro-replacement and the deep soil mixing treatment methods used in the project. The use of plate bearing tests and field instrumentation to monitor the performance of the stone columns and soil mixing ground treatment methods is also discussed. This paper also provides a brief overview of other treatment methods implemented in this high-speed railway project such as a pile embankment with geogrids and removal/replacement works.