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Post-tensioned cross-laminated timber (PT-CLT) walls have been demonstrated to be a low-damage seismic force-resisting system (SFRS) due to their self-centering capability. However, there is still a need to examine the seismic performance of such SFRS in high-seismic risk zones. This study evaluates the seismic performance of 6-, 9-, and 12-storey PT-CLT shear wall buildings in Vancouver, Canada, equipped with buckling-restrained axial fuses. The prototype buildings were designed using the displacement-based design method, and the assessment considered the most recent seismic hazard model provided in the 2020 National Building Code of Canada. To conduct nonlinear response history analysis (NLRHA) and incremental dynamic analysis (IDA), numerical models were developed in OpenSeesPy and calibrated based on component- and system-level experimental tests. The NLRHA and IDA results demonstrate that all the studied buildings have adequate collapse margin ratios, with less than a 10% chance of collapsing at the maximum considered earthquakes. [ABSTRACT FROM AUTHOR]

Corrugated web plate girders (CWPGs) have grown in popularity in Canada in recent years because of their economic efficiency. Although research on the flexural performance of such members has increased in recent years, there are still additional advancements that can be made in their design, particularly in the calculation of lateral torsional buckling resistance. However, no research has been presented in Canada on this subject, and very minimal research has been published on CWPGs with sinusoidal corrugated webs. The purpose of this study was to examine the lateral torsional buckling strength of CWPGs with sinusoidal corrugated web profiles through experimental analysis of CWPGs that are currently being used in Canada. Nine simply supported specimens were loaded and failed in lateral torsional buckling (LTB). The nine specimens were chosen according to size in order to observe variations in LTB strength based on web thickness, web depth, and variations in identical beams. All beams tested recorded strengths far greater than conventional design strength, confirming the conservative nature of the current design procedure. As web thickness increased, a trend of ultimate capacity increasing was observed. The depth of the webs had no significant effect on LTB strength apart from what was gained by increasing the depth of the flanges. Based on the results, an equivalent web thickness equation is proposed for the purpose of calculating a more precise LTB resistance. A numerical analysis was run on a wide range of beam sizes and compared with the physical testing results. It was determined that the proposed equation effectively captured the physical testing results among more than just the tested beams. However, future work should further examine the reliability of the proposed equation by testing more specimens and/or using the finite-element method. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ductile concentrically braced frames (CBFs) are commonly used seismic force-resisting systems in seismic regions. The capacity design approach described in the state-of-the-art seismic codes of the US, Canada, and Turkey defines a design procedure for columns and girders via two structural analyses that intend to capture the nonlinear behavior of CBFs while assuming braces in different stories undergo yielding or buckling, simultaneously. It would be, therefore, befitting to question the validity of the anticipated mechanism controlling CBF design considering limited studies in the literature. In addition to chevron and two-story Xbraced frame configurations, an alternative design approach is proposed without changing the current habits in the industry. The present study aims to investigate whether or not the capacity design approach adopted by the leading seismic codes is consistent with the nonlinear behavior of CBFs via pushover analyses and time-history analysis. For the proto-type CBFs, peak and residual inter-story drift ratios were compared as well as ductility demands of braces. In conclusion, it is found that mechanism scenarios stimulated in current seismic codes are unlikely to occur under an earthquake event and the proposed balanced design approach provided significant reductions on seismic demands, only with an 8% increase in weight. [ABSTRACT FROM AUTHOR]

The intensity and frequency of extreme rainfall events have increased in North America and the world due to climate change. Extreme rainfall events, characterized by a heavy volume of rainfall in a short duration, have triggered the onset of urban flash floods. Over the years, flash flooding has been reported in different cities in Canada, which resulted in many losses. Subsequently, different green roofing systems have been adopted to control urban stormwater runoff as part of Nature-Based Solutions (NBS) to mitigate urban flood and build a flood-resilient city. Currently, no specific widely recognized standard or code is dedicated to determining the hydrological performance of green roofs as a whole system. Moreover, there are no test protocols to regulate the design of green roof systems in the market. A comprehensive literature review examines existing research methods adopted to evaluate influencing parameters affecting the hydrological performance of NBS-CR. The results indicate several limitations in experimental and field investigations. Consequently, to address these limitations, it is essential to formulate a multi-functional work plan to develop a standardized test method that can become a common platform for the roofing industry to test and quantify the hydrological performance of their systems. [ABSTRACT FROM AUTHOR]

The prohibitive costs of small-scale solar photovoltaic (PV) racks decrease PV adoption velocity. To overcome these costs challenges, an open hardware design method is used to develop two novel variable tilt racking designs. These are the first stilt-mounted racking designs that allow for the manual change of the tilt angle from zero to 90 degrees by varying the length of cables. The racks are designed using the calculated dead, wind, and snow loads for Canada as a conservative design for most of the rest of the world. Structural capacities of the wooden members are then ascertained and the resisting bending moment, shear force, tensile force, and compressive force is calculated for them. A structural and truss analysis is performed to ensure that the racking design withstands the applicable forces. Moreover, the implications of changing the tilt angle on the wooden members/cables used to build the system are also determined. The systems offer significant economic savings ranging from one third to two thirds of the capital expenses of the commercially available alternatives. In addition, the racking designs are easy-to-build and require minimal manufacturing operations, which increases their accessibility. The stilt-mounted designs can be employed for agrivoltaic settings while allowing farm workers shaded, ergonomic access to perform planting, weeding, and harvesting. [ABSTRACT FROM AUTHOR]

A commissioning test of the deep-burial simulator at Queen's University, Canada, was conducted on a 3.05-m-diameter steel-reinforced polyethylene pipe to evaluate the behavior and design of this pipe class under deep burial. The diameter change measurements indicated that friction on the side walls was mitigated ensuring that the surface load was transferred to the pipe. Measurements of the displacement and rotation of the surface loading plates and strain in the steel reinforcing strips combined with visual observations after exhumation indicated that the pipe failed due to yielding of the steel reinforcing ribs. The surface pressure that the pipe was able to withstand exceeded the maximum burial depth specified by the manufacturer. Comparisons are also made between the experimental thrust forces at the springline and estimates from two design codes and a finite-element estimate; all were similar, with the rate of thrust increase with overburden pressure from the computer analysis approximately 8% larger than the measurement. Thus, the experimental results confirm that use of finite-element and code-equation analyses to design this pipe class for deep-burial conditions appear to be appropriate. [ABSTRACT FROM AUTHOR]

• Combined out-of-plane bending and compression is an inevitable loading condition for CLT walls. • The experimental program consisted of 36 CLT panel specimens. • The damage was caused by the local buckling near the mid-height of the outer layer on the compression side. • Signs of shear failure of cross layers were evident almost simultaneously with the outer layer failure. • The interaction equations specified in the Canadian design standard are appropriate for the CLT panels under small load eccentricities. Combined out-of-plane bending and compression is an inevitable loading condition for cross-laminated timber (CLT) walls due to the out of plumbness, initial panel curvature and load eccentricity. Because of the weaker cross layers, the mechanical performance and failure mode of the CLT panels under such loading significantly differ from those of the other wood members, such as sawn timber and glulam. This experimental study focuses on investigating the behavior of CLT panels under the stated loading scenario. The experimental program consisted of 36 specimens, including 12 five-layer CLT panels provided by two Canadian manufacturers, as well as 12 three-layer and 12 five-layer CLT panels provided by a Chinese manufacturer. All the specimens were tested in Canada and China, respectively, using the same test setup. It was found that in the majority of the specimens, the damage was caused by the local buckling near the mid-height of the outer layer on the concave compression side at about 45%–60% of the ultimate failure load and 25%–35% of the ultimate deflection. The dominant failure mode was characterized as the crushing yield of the outer layer on the concave side (fibers in compression) near the mid-height after the local buckling progressed. Signs of shear failure of cross layers were evident almost simultaneously with the outer layer failure. Hence, although the dominant failure mode was likely triggered by the fracture in the cross layers due to rolling shear, the load-carrying capacity of the CLT panels under the combined out-of-plane bending and compression is governed by the compression failure of the longitudinal outer layers. It was found that a cross-layered panel can maintain its integrity before failure. It was also noted that the interaction equations specified in the Canadian design standard are appropriate for the CLT panels under small load eccentricity, while for panels that have large load eccentricity, the appropriateness of the interaction equation is questionable. Based on the test results obtained, the validity of the interaction equation for the prediction of the load-carrying capacity of CLT columns, specified in the CSA O86-19, is confirmed for cases in which P f / P r > 0.5 and M f / M r < 0.3. For the cases of P f / P r < 0.5 and M f / M r > 0.3 , modification of the equation is needed. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop spatiotemporal whole-stem wood quality prediction models for a suite of end-product-based fibre attribute determinates for jack pine (Pinus banksiana Lamb.) and red pine (Pinus resinosa Aiton): specifically, for wood density (Wd), microfibril angle (Ma), modulus of elasticity (Me), fibre coarseness (Co), tracheid wall thickness (Wt), tracheid radial diameter (Dr), tracheid tangential diameter (Dt), and specific surface area (Sa). Procedurally, these attributes were determined for each annual ring within pith-to-bark xylem sequences extracted from 610 jack pine and 223 red pine cross-sectional disks positioned throughout the main stem of 61 jack pine and 54 red pine sample trees growing within even-aged monospecific stands in central Canada. Deploying a block cross-validation-like approach in order to reduce serial data dependency and enable predictive performance assessments, species-specific calibration and validation data subsets consisting of cumulative moving average values were systematically generated from the 27,820 jack pine and 11,291 red pine attribute-specific annual ring values. Graphical, correlation, regression and validation analyses were used to specify, parameterize and assess the predictive performance of tertiary-level (ring-disk-tree) hierarchical mixed-effects whole-stem equations for each attribute by species. As a result, the jack pine equations explained 46, 66, 74, 63, 59, 72, 42 and 48% of the variation in Wd, Ma, Me, Co, Wt, Dr, Dt and Sa, respectively. The red pine equations explained slightly higher levels of variation except for Me: 50, 71, 31, 83, 72, 78, 56 and 71% of the variation in Wd, Ma, Me, Co, Wt, Dr, Dt and Sa, respectively. Graphical assessments and statistical metrics related to attribute and species-specific residual error patterns and goodness-of-fit, lack-of-fit and predictive error metrics, revealed an absence of systematic bias, misspecification or aberrant predictive performance. Consequently, the resultant parameterized models were acknowledged as acceptable functional descriptors of the intrinsic spatiotemporal cumulative developmental patterns of the studied end-product fibre attribute determinates, for these two pine species. Although predicted development patterns were similar between the species with the greatest degree of nonlinearity occurring before a cambial age of approximately 30 years, irrespective of attribute, jack pine exhibited a greater degree of nonlinearity in the Wd and Dt developmental trajectories, whereas red pine exhibited a greater degree of nonlinearity in the Ma, Me, Co, Wt, Dr and Sa developmental trajectories. Potential biomechanical linkages underlying the observed attribute distribution patterns, as well as the potential utility of the models in forest management, are also discussed. [ABSTRACT FROM AUTHOR]

Buried medium-density polyethylene (MDPE) pipes are widely used for gas distribution systems in Canada and worldwide. When exposed to geotechnical hazards such as ground movements, these pipes can experience excessive distresses, leading to leaking or failure. This research investigates the effects of ground movement near a tee connection of MDPE gas distribution pipes. If the ground movement is parallel to a branch, the branch pipe experiences an axial force, and the main pipe experiences bending deformation/strains. The axial forces and the wall strains were investigated in this study using full-scale laboratory tests. Test results showed that the axial force on the branch and strains on the main pipe depend on the burial depth, backfill soil density, and the pipe diameter due to the effects on the shearing resistance of the soil. The soil shearing resistance was less for shallow buried pipes, resulting in a lower axial force in the branch but higher bending strain in the main pipe. The axial pullout resistance of the main pipe also contributed to the wall strains of this laterally loaded pipe at large displacements. The conventional beam-on-elastic foundation solution reasonably estimated the pipe wall strains within the linear range of deformations. Nonlinear analyses, including lateral and axial soil springs, are recommended to capture the nonlinear responses at large displacements. [ABSTRACT FROM AUTHOR]

While damping devices can provide supplemental damping to mitigate building vibration due to wind or earthquake effects, integrating them into the design is more complex. For example, the Canadian code does not provide building designs with inline friction dampers. The objective of this present article was to study the overstrength, ductility, and response modification factors of concrete frame buildings with inline friction dampers in the Canadian context. For that purpose, a set of four-, eight-, and fourteen-story ductile concrete frames with inline seismic friction dampers, designed based on the 2015 National Building Code of Canada (NBCC), was considered. The analyses included pushover analysis in determining seismic characteristics and dynamic response history analysis using twenty-five ground motion records to assess the seismic performance of the buildings equipped with inline seismic friction dampers. The methodology considered diagonal braces, including different 6 m and 8 m span lengths. The discussion covers the prescribed design values for overstrength, ductility, and response modification factors, as well as the performance assessment of the buildings. The results revealed that increasing the height of the structure and reducing the span length increases the response modification factors. [ABSTRACT FROM AUTHOR]

The seismic resilience of structures can be quantified through rigorous seismic assessment. Because no detailed guideline is available for nonlinear modelling parameters and the corresponding acceptance criteria for the seismic evaluation and upgrading of steel structures in Canada, the structural commentary of the National Building Code of Canada suggests using ASCE 41, which has been adopted as a standard for seismic evaluation and retrofit of buildings in the United States (U.S.). However, because the steel design standards in Canada and the U.S. are different, their applicability to steel structures in Canada needs to be investigated. To this end, this paper critically reviews the nonlinear modelling parameters and acceptance criteria, and then recommends whether these values need to be revised or are adopted as is for the seismic evaluation and upgrading of steel structures in Canada. A numerical example of a steel moment-resisting frame is presented to demonstrate the recommended parameters being used for seismic evaluation. [ABSTRACT FROM AUTHOR]

Host–parasite coevolution may lead to patterns of local adaptation in either the host or parasite. For parasites with complex multi‐host life cycles, this coevolution may be more challenging as they must adapt to multiple geographically varying hosts. The tapeworm Schistocephalus solidus exhibits some local adaptation to its second intermediate host, threespine stickleback, to which the parasite is strictly specialized. However, the tapeworm's adaptation to its first intermediate host (any of a number of copepod species) is not documented. We investigated if there was local adaptation and host specify in the tapeworm Schistocephalus solidus to its copepod first intermediate hosts. We exposed copepods from five lakes in Vancouver Island (BC, Canada) to local (i.e. same lake) and foreign tapeworms in a reciprocal exposure experiment. Results indicate that the tapeworm is not locally adapted to the copepods. Instead, we observed moderate‐effect host specificity, infection rates being higher in certain copepod species than in others. Infection rates also varied among cestode populations. These results show that although S. solidus infects multiple copepod genera, they are not equally competent hosts. Differences in S. solidus epidemiology among lakes is likely to be driven more by this partial specialization, than by local adaptation to first intermediate hosts. [ABSTRACT FROM AUTHOR]

The constant fluctuation of thermal loads on steel members, especially during construction, causes non-uniform distributions of temperatures, resulting in possible constructional and structural defects leading to unfavorable thermally induced responses and potential safety risks. The Canadian Highway Bridge Design Code (CHBDC) provides one thermal gradient variation profile without accounting for the differences in the geometrical parameters of the steel members and the variations in the climate regions of Canada. Therefore, in this study, three-dimensional finite element (FE) thermal simulations were conducted to investigate the maximum effective temperatures and positive vertical thermal gradients for different Canadian climate regions. Parametric studies were performed to conduct the FE thermal analysis using the thermal model validated in ANSYS. The comprehensive study results showed that Canada could be divided into two main zones for vertical thermal gradient calculations, meaning that one stationary thermal gradient profile cannot be applicable to all climate regions of Canada, as recommended by the CHBDC. Based on the FE thermal analysis results, empirical formulas as a function of the significant parameters were proposed to predict the maximum effective temperature and thermal gradient variations of the steel I-girder. The predicted maximum effective temperature and thermal gradient variation values were found to be highly correlated with the FE values with coefficients of determination R2 of approximately 0.97 and 0.98, respectively. [ABSTRACT FROM AUTHOR]

The National Research Council Canada (NRC) is currently developing seismic evaluation and upgrading guidelines for existing buildings in Canada. The seismic evaluation guidelines consist of three tiers of seismic evaluation procedures, that is, Tier 1 Quick Evaluation, Tier 2 Deficiency-Based Evaluation, and Tier 3 Detailed Evaluation. This paper presents the Tier 1 Quick Evaluation procedure, which aims to update the initial quick evaluation procedure in the existing seismic evaluation guidelines developed by the NRC in early 1990s. The proposed procedure covers seismic assessment of both structural and non-structural elements, and requires the review of construction documents, on-site inspection, and calculations. A set of checklists are contained to uncover potential key seismic deficiencies of the building under evaluation. The checklists are in the form of evaluation statements that relate to potential seismic deficiencies in the structural systems and non-structural components. The proposed procedure is demonstrated by conducting the seismic evaluation of an existing building that is part of a pilot study. [ABSTRACT FROM AUTHOR]

The desire of using sustainable materials has reignited the interest in timber-based construction. Researchers and practitioners are developing novel timber-based structural solutions. Cross-laminated timber (CLT)-coupled wall is a recently proposed system for potential use in mid- and high-rise timber construction. The National Building Code of Canada, however, does not include this system and, consequently, the seismic force modification factors are not available. This study evaluated the ductility-related force modification factor (Rd) using the FEMA P-695 procedure. Nine archetype buildings were designed considering different design parameters: building storey height, CLT wall configuration, and coupling ratios. Using 30 ground motion records (bi-directional), rigorously selected for seismicity of Vancouver, BC, Canada, incremental dynamic analyses were performed. Collapse margin ratios were calculated to assess the adequacy of the trial Rd factors. Using an over-strength factor of 1.5, Rd = 4 is found to be acceptable for this system. [ABSTRACT FROM AUTHOR]

Our understanding of the present‐day state and evolution of the Canadian and Alaskan mantle is hindered by a lack of absolute P‐wavespeed constraints that provide complementary sensitivity to composition in conjunction with existing S‐wavespeed models. Consequently, cratonic modification, orogenic history of western North America and complexities within the Alaskan Proto‐Pacific subduction system remain enigmatic. One challenge concerns the difficulties in extracting absolute arrival‐time measurements from often‐noisy data recorded by temporary seismograph networks required to fill gaps in continental and global databases. Using the Absolute Arrival‐time Recovery Method (AARM), we extract >180,000 new absolute arrival‐time residuals from seismograph stations across Canada and Alaska and combine these data with USArray and global arrival‐time data from the contiguous US and Alaska. We develop a new absolute P‐wavespeed tomographic model, CAP22, spanning North America that significantly improves resolution in Canada and Alaska over previous models. Slow wavespeeds below the Canadian Cordillera sharply abut fast wavespeeds of the continental interior at the Rocky Mountain Trench in southwest Canada. Slow wavespeeds below the Mackenzie Mountains continue farther inland in northwest Canada, indicating Proterozoic‐Archean metasomatism of the Slave craton. Inherited tectonic lineaments colocated with this north‐south wavespeed boundary suggest that both the crust and mantle may control Cordilleran orogenic processes. In Alaska, fast upper mantle wavespeeds below the Wrangell Volcanic Field favor a conventional subduction related mechanism for volcanism. Finally, seismic evidence for the subducted Kula and Yukon slabs indicate tectonic reconstructions of western North America may require revision. Plain Language Summary: Our understanding of the plate tectonic history of North America is incomplete. Outstanding questions include: 1. Have ancient parts of the North American plate been modified over time or remained unchanged since assembly? 2. What processes produced the differing shape of the western Canadian Cordilleran Mountains along their length? 3. Can we image the old plate remnants that were recycled back into the mantle at subduction zones to better understand how North America was formed? We use earthquakes that produce P‐waves, recorded at distant receivers, to seismically image the mantle below North America, including new data from Canada and Alaska for the first time. Slower‐than‐expected seismic wavespeeds that continue from the west coast inland toward north‐central Canada suggest the ancient Slave Craton has been modified by chemical processes ≥500 million years ago. An abrupt seismic wavespeed boundary perpendicular to the Canadian Cordilleran Mountains suggests their shape may be controlled by pre‐existing zones of weakness in the crust and mantle. Fragments of old tectonic plates, stuck in the mantle below western North America and Alaska, suggest our understanding of the final stages of assembly of modern North America requires revision. Key Points: North American absolute P‐wavespeed tomographic model incorporating dense seismic networks in Canada and AlaskaImaged fast wavespeed subducted remnants suggest revision of Alaskan and proto Pacific subduction models is necessarySlow wavespeed structures imply Slave Craton metasomatic modification and tectonic inheritance during Cordilleran orogenesis [ABSTRACT FROM AUTHOR]

The Arctic is the fastest warming biome on the planet, and environmental changes are having striking effects on freshwater ecosystems that may impact the regional carbon cycle. The metabolic state of Arctic lakes is often considered net heterotrophic, due to an assumed supply of allochthonous organic matter that supports ecosystem respiration and carbon mineralization in excess of rates of primary production. However, lake metabolic patterns vary according to regional climatic characteristics, hydrological connectivity, organic matter sources and intrinsic lake properties, and the metabolism of most Arctic lakes is unknown. We sampled 35 waterbodies along a connectivity gradient from headwater to downstream lakes, on southern Victoria Island, Nunavut, in an area characterized by low precipitation, organic-poor soils, and high evaporation rates. We evaluated whether lakes were net autotrophic or heterotrophic during the open water period using an oxygen isotopic mass balance approach. Most of the waterbodies were autotrophic and sites of net organic matter production or close to metabolic equilibrium. Autotrophy was associated with higher benthic primary production, as compared to its pelagic counterpart, due to the high irradiance reaching the bottom and efficient internal carbon and nutrient cycling. Highly connected midstream and downstream lakes showed efficient organic matter cycling, as evidenced by the strong coupling between gross primary production (GPP) and ecosystem respiration, while decoupling was observed in some headwater lakes with significantly higher GPP. The shallow nature of lakes in the flat, arid region of southern Victoria Island supports net autotrophy in most lakes during the open water season. Ongoing climate changes that lengthen the ice-free irradiance period and increase rates of nutrient evapoconcentration may further promote net autotrophy, with uncertain long-term effects for lake functioning., (© 2024 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

The design provisions for internal glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) columns have been recently under consideration by design committees in Canada and around the world due to new advancements in understanding the behavior of GFRP-RC columns. The slenderness limit is a critical design parameter differentiating between the first- and second-order analyses of GFRP-RC columns. The existing slenderness limits in design standards were calibrated using deterministic approaches. In this study, a novel reliability-based approach was utilized to quantify the reliability index associated with the slenderness limit to calibrate and propose optimized reliability-based slenderness limits for CSA S806 and CSA S6, for the first time. The method takes the advantage of artificial intelligence and incorporates a comprehensive experimental database. [ABSTRACT FROM AUTHOR]

The 2020 National Building Code of Canada (NBCC) seismic hazard model (SHM) marks a comprehensive update over its predecessor (NBCC 2015). For different regions in Canada, this will have an impact on the design of new buildings and performance assessment of existing ones. In the present study, a recently developed hybrid building system with reinforced concrete (RC) moment-resisting frames and cross-laminated timber (CLT) infills is assessed for its seismic performance against the latest SHM. The six-story RC-CLT hybrid system, designed using the direct displacement-based method, is located in Vancouver, Canada. Along with very high seismicity, southwestern British Columbia is characterized by complex seismotectonics, consisting of subduction, shallow crustal, and in-slab faulting mechanisms. A hazard-consistent set of 40 ground motion pairs is selected from the PEER and KiK-net databases, and used to estimate the building's seismic performance. The effects of using steel slit dampers (associated with large hysteresis loops) and flag-shaped energy dissipators (associated with the recentering capability) are investigated. The results indicate that the hybrid system has good seismic performance with a probability of collapse of 2–3% at the 2475-year return period shaking intensity. The hybrid building with steel slit dampers exhibits a collapse margin ratio of 2.8, which increases to 3.5–3.6 when flag-shaped dissipators are used. The flag-shaped dissipators are found to significantly reduce the residual drift of the hybrid building. Additionally, the seismic performance of the hybrid building equipped with flag-shaped dissipators is found to improve marginally when the recentering ratio is increased. [ABSTRACT FROM AUTHOR]

This paper presents the results of a benchmarking study on face support practice in seismically active mines in Australia and Canada. The choice of ground support strategies is based on the anticipated strainburst hazard as well as corporate, legislative, and operational requirements. Although mines appear to employ similar face support standards, using friction rock stabilizers and mesh, the details and the resulting coverage vary from site to site. The variations in design and coverage result in significantly different residual risks. The case is made for documenting strainburst events at the mining face and using this information to formally assess the effectiveness of implemented face support practice at the various mine sites. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of revised seismic hazard values in the National Building Code of Canada (NBCC 2015) on the design of reinforced-concrete (RC) shear wall buildings. Five buildings with different heights located in three cities in Canada are selected. Toronto, Montreal, and Vancouver are selected to represent low, medium, and high seismic hazard zones. The buildings are designed according to the NBCC 2010 and then checked against the updated design spectral accelerations of the NBCC 2015. The seismic demands are compared, and the need for retrofit of existing walls is evaluated. The analyses showed that the maximum interstory drift ratios increased specially for buildings in Vancouver. The shear force and bending moment demands increased for most buildings in Vancouver by up to 32% and 60%, respectively. A significant decline in the moment overstrength ratio was noticed for walls in Vancouver, which indicates that flexural strengthening might be mandatory for these walls. Moreover, the code changes had a great negative impact on the walls' ductility for buildings in Vancouver due to the higher deformations exhibited. Several retrofit techniques available in the literature were discussed to enhance the flexural strength and ductility of RC shear walls as remedies for the consequences of the updated seismic hazard in Canada. [ABSTRACT FROM AUTHOR]

Coupled shear walls (CSW) are an efficient lateral load-resisting system. Their seismic performance depends primarily on their coupling beams (CBs) ability to provide adequate stiffness and strength. However, many existing buildings with CSW resisting system were designed and constructed according to old codes and standards with insufficient requirements for seismic design. These systems feature unsatisfactory behaviour and prematurely collapse in case of major earthquake events. Therefore, their seismic retrofit is urgently needed. The main objectives of this study are, i) evaluate and compare the seismic performance of CSWs designed to old and new codes; ii) highlight the deficiencies of CSWs designed to old codes; iii) investigate a retrofit method using externally bonded (EB) carbon fibre reinforced polymer (CFRP) composites to enhance the seismic response of deficient CSWs. To that end, a 20-story CSW is considered with different design details including one according to old National Building Code of Canada (NBCC) before the 1970s and the other one designed consistent with the new NBCC 2015 and the Canadian Standard Association, CSA A23.3–14, for Eastern seismic Canadian zone. The nonlinear analyses of CSWs under earthquake records are conducted in two steps. At first, the nonlinear time-history analyses of two types of CSWs are carried out using RUAUMOKO program and the deficiencies of old-designed CSW are identified through the comparison of obtained results. In the second step, the old design CSW is retrofitted using CFRP sheets and reanalysed to investigate the benefits of the retrofit technique in mitigating the shortcomings. The results indicate that CFRP retrofitting is an efficient method to enhance the seismic performance of deficient old CSWs in terms of story displacement, inter-story drift, CBs rotation, and ductility demand. [ABSTRACT FROM AUTHOR]

Lack of robustness is a major barrier to foster a sustainable cyanobacterial biotechnology. Use of cyanobacterial consortium increases biodiversity, which provides functional redundancy and prevents invading species from disrupting the production ecosystem. Here we characterized a cyanobacterial consortium enriched from microbial mats of alkaline soda lakes in BC, Canada, at high pH and alkalinity. This consortium has been grown in open laboratory culture for 4 years without crashes. Using shotgun metagenomic sequencing, 29 heterotrophic metagenome-assembled-genomes (MAGs) were retrieved and were assigned to Bacteroidota, Alphaproteobacteria , Gammaproteobacteria , Verrucomicrobiota , Patescibacteria , Planctomycetota , and Archaea. In combination with metaproteomics, the overall stability of the consortium was determined under different cultivation conditions. Genome information from each heterotrophic population was investigated for six ecological niches created by cyanobacterial metabolism and one niche for phototrophy. Genome-resolved metaproteomics with stable isotope probing using 13C-bicarbonate (protein/SIP) showed tight coupling of carbon transfer from cyanobacteria to the heterotrophic populations, specially Wenzhouxiangella. The community structure was compared to a previously described consortium of a closely related cyanobacteria, which indicated that the results may be generalized. Productivity losses associated with heterotrophic metabolism were relatively small compared to other losses during photosynthesis. [ABSTRACT FROM AUTHOR]

A lower shear strength and higher compressibility impose major challenges for construction on organic soils. Cementitious materials have been effectively used in the improvement of the engineering properties of mineral soils with low organic contents. However, limited studies have been devoted to the stabilization of the organic soils commonly encountered in forested regions in Canada. The present study investigated the effects of pulp mill fly ash (PFA) on the compressibility of a natural soil consisting of 26% organic matter. Fall-cone and oedometer tests were conducted on organic soil mixed with different PFA dosages (5%, 10%, 20%, 30%, 40%, and 50%), as well as on untreated soil samples. The mineralogical and microstructural aspects of PFA-treated organic soil were examined using scanning electron microscope and energy-dispersive X-ray spectroscopy techniques. The results suggest that when the organic soil was treated with PFA, its undrained shear strength and compressibility behavior were improved. Moreover, the potentially large settlement of organic soil can be reduced by the addition of PFA. The primary and secondary compression index (Cc and Cα, respectively) values decreased significantly when compared with the untreated organic soil, indicating that PFA stabilizers can effectively improve the creep behavior of organic soils. These findings indicate that the beneficial utilization of PFA for the stabilization of organic soils could be a practical step toward the environmentally sound management of this waste byproduct. [ABSTRACT FROM AUTHOR]

The lateral strength and stiffness requirements due to wind loads usually govern the design of tall buildings. The current building codes in the US, Canada, and Europe recognize the first significant yield point as an ultimate limit state. Consequently, the current design practices ignore the plastic capacity of structural systems in the nonlinear range, which could result in overdesigned buildings. Thus, the classical linear-elastic design arguments shall be reexamined with consideration of performance-based wind design (PBWD) approaches, innovative technologies, and materials. We are presenting two companion papers to demonstrate the benefits of considering the nonlinear capacity of structural systems in the design of wind-excited buildings. In this paper, Part I, we have postulated and then proved the capability of self-centering systems in controlling the possible damage accumulation in structural systems subjected to along-wind loads. Our arguments are based on an extensive parametric study through nonlinear time history analyses considering peak and residual ductility-demands, normalized hysteretic energy dissipation, and the rate of damage accumulation as performance indicators. Overall, the results of the parametric study revealed that self-centering systems could benefit the most from the ductility-based design due to their inherent recentering capability, higher energy dissipation, and lower sensitivity to wind duration. Consistent with the notion of PBWD, for self-centering systems, the companion Part II paper demonstrates the benefits of the ductility-based wind design in terms of economics and safety through structural reliability analysis. [ABSTRACT FROM AUTHOR]

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Due to the efficiency, sustainability, and advances in firefighting technologies, the allowable height for wood buildings was increased from 4 to 6 storeys in 2015 and will be further increased to 12 storeys in the 2020 edition of the National Building Code of Canada, as a result of the advent and application of mass timber products. To match the development in the industry and the increasing need in the market for highly skilled timber engineers, structural timber design curricula at the university level must evolve to train the next generation of practitioners. At most Canadian universities, structural timber design courses are mainly provided in civil engineering departments. In this study, 31 accredited civil engineering programs in Canada were reviewed for structural wood design content at undergraduate and graduate levels based on two surveys conducted in 2018 and 2020. In the 2018 survey, the percentage of structural timber design content was estimated and compared with other engineering materials (e.g., steel, concrete, and masonry), and a similar survey was repeated in 2020 to determine if any significant changes had occurred. In early 2021, two complementary questionnaires were sent to the instructors of timber-related courses across the country to collect quantitative information, including enrollment statistics, percentage dedicated to timber design in combined material courses, and potential topics deemed critical to support the design of modern timber structures. Based on the responses provided, and also on the availability of resources and the research ongoing, the content for five advanced-level courses is proposed to address the needs of the timber design community. The findings presented in this paper will assist the timber industry, government agencies, and educational institutions in effecting potential changes to university curricula to educate the next generation of timber design professionals who will possess the necessary skills and knowledge to meet the challenges in designing modern mass timber structures. [ABSTRACT FROM AUTHOR]