EBA Engineering Consultants Ltd

Edmonton, Canada

EBA Engineering Consultants Ltd

Edmonton, Canada
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Phillips D.H.,Queen's University of Belfast | Nooten T.V.,Flemish Institute for Technological Research | Bastiaens L.,Flemish Institute for Technological Research | Russell M.I.,Queen's University of Belfast | And 11 more authors.
Environmental Science and Technology | Year: 2010

The Monkstown zero-valent iron permeable reactive barrier (ZVI PRB), Europes oldest commercially-installed ZVI PRB, had been treating trichloroethene (TCE) contaminated groundwater for about 10 years on the Nortel Network site in Northern Ireland when cores from the reactive zone were collected in December, 2006. Groundwater data from 2001-2006 indicated that TCE is still being remediated to below detection limits as the contaminated groundwater flows through the PRB. Ca and Fe carbonates, crystalline and amorphous Fe sulfides, and Fe (hydr)oxides have precipitated in the granular ZVI material in the PRB. The greatest variety of minerals is associated with a ∼1-2 cm thick, slightly cemented crust on top (up-gradient influent entrance) of the ZVI section of the PRB and also with the discontinuous cemented ZVI material (∼23 cm thick) directly below it. The greatest presence of microbial communities also occurred in the up-gradient influent portion of the PRB compared to its down-gradient effluent section, with the latter possibly due to less favorable conditions (i.e., high pH, low oxygen) for microbial growth. The ZVI filings in the down-gradient effluent section of the PRB have a projected life span of >10 years compared with ZVI filings from the continuous to discontinuous cemented up-gradient ZVI section (upper ∼25 cm) of the PRB, which may have a life span of only ∼2-5 more years. Supporting Information from applied, multi-tracer testing indicated that restricted groundwater flow is occurring in the upper ∼25 cm of the ZVI section and preferential pathways have also formed in this PRB over its 10 years of operation. © 2010 American Chemical Society.

Wang Y.,EBA Engineering Consultants Ltd. | Moore I.D.,Queen's University
ICPTT 2013: Trenchless Technology - The Best Choice for Underground Pipeline Construction and Renewal, Proceedings of the International Conference on Pipelines and Trenchless Technology | Year: 2013

The structural design of joints in highway culverts requires evaluation of expected values of both the shear force across the joint and the joint rotation that result from vehicle loads. This paper describes new design equations that have recently been developed for estimating shear force and rotation in bell and spigot joints for both rigid and flexible culverts. The equations are exact closed form solutions based on the modeling of the pipes as elastic beams, and the Winkler soil model (where the soil stiffness is represented using a series of elastic springs). The kinematic assumptions are explained, and the equations are presented. Comparisons are included between estimates of joint rotations under surface loads and rotations measured during full-scale laboratory experiments. The paper concludes with a discussion of how shear force and rotation depend on pipe diameter, pipe stiffness and burial depth. © ASCE 2013.

Taghaddos H.,University of Alberta | Soleymani H.R.,University of Alberta | Robson J.D.,EBA Engineering Consultants Ltd
ACI Materials Journal | Year: 2010

Most standardization agencies allow small-cylinder specimens (100 x 200 mm [4x8 in.]) to be used in compressive strength concrete testing. Some engineers are still skeptical about using small cylinders, however, as they believe that compressive strength testing results from small cylinders are too varied. Limited studies have been conducted regarding the precision of small cylinders compared to precision studies for conventional cylinders (150 x 300 mm [6x12 in]). This paper describes the results of a comparative concrete testing program conducted by 15 laboratories in Edmonton, AB, Canada, over the past 10 years. This study attempted to develop within-laboratory (repeatability) and betweenlaboratory (reproducibility) precision indexes for small and conventional concrete specimens by analyzing more than 2700 compressive strength concrete testing data within a compressive strength range of 17 to 57 MPa (2500 to 8300 psi). Copyright © 2010, American Concrete Institute. All rights reserved,.

Kim I.-A.,University of British Columbia | Trosper R.L.,University of British Columbia | Trosper R.L.,University of Arizona | Mohs G.,Stsailes | Mohs G.,EBA Engineering Consultants Ltd.
Forest Policy and Economics | Year: 2012

We have identified cultural uses of non-timber forest products (NTFPs) in the Sts'ailes, a group within the central Coast Salish First Nation in British Columbia, Canada. The non-timber forest products are culturally important and often accessible to local people. We undertook a community-based participatory case study of the cultural uses of non-timber forest products within the Sts'ailes traditional territory. We used semi-structured interviews, ethnography, and secondary documents (e.g. maps and supporting documents) to provide in-depth understanding of the NTFP uses. Sts'ailes people use NTFPs by (1) gathering plants for food and medicine, (2) making materials from the plants, (3) making spiritual regalia and paints for winter ceremonials, and (4) brushing with cedar branches as spiritual practices. Forest environments and NTFPs provide secured environment for spiritual bathing and other spiritual practices and cedar branches are essential to use for purification. Because of these uses, Canadian governments need to consult and accommodate the Sts'ailes people when undertaking forestry operations. In addition, Sts'ailes use of the land demonstrates their continued possession of it. © 2012 Elsevier B.V.

Khalili A.,EBA Engineering Consultants Ltd. | Wijewickreme D.,University of British Columbia | Ward Wilson G.,University of British Columbia
Canadian Geotechnical Journal | Year: 2010

The idea of mixing mine tailings and waste rock to form "paste rock" prior to disposal is now receiving significant attention from the point of view of sustainable mine waste management practices. This approach has been viewed as a favourable alternative to traditional methods of mine waste disposal because paste rock has the potential to overcome deficiencies (e.g., acid rock drainage and liquefaction-induced failures) associated with traditional methods. To advance the current limited knowledge, a laboratory research program was undertaken to study the mechanical response of paste rock. Testing was undertaken on paste rock specimens prepared so that the tailings would "just fill" the void spaces within the waste rock particle skeleton. The findings suggest that the material is unlikely to experience flow deformation under monotonic shear loading conditions, at least up to the tested initial effective confining stress conditions of 400 kPa. The monotonic shear response of paste rock was found to be similar to that of rock-only material; this finding is in agreement with previous observations from one-dimensional consolidation testing where it had been shown that the rock particle skeleton would carry almost 90% of the externally applied stress on a given paste rock mass.

Wijewickreme D.,University of British Columbia | Khalili A.,EBA Engineering Consultants Ltd. | Ward Wilson G.,University of British Columbia
Canadian Geotechnical Journal | Year: 2010

Mixing of waste rock and tailings as a homogeneous mixture (referred to as "paste rock") has been suggested as a favourable approach to overcome deficiencies associated with traditional methods of mine waste disposal. In consideration of the current limited understanding of the fundamental mechanical response of paste rock, a laboratory research pro-gram was undertaken to investigate the monotonic and cyclic shear response of paste rock. This paper presents the findings from undrained cyclic triaxial shear testing conducted on saturated paste rock specimens reconstituted such that the tailings would "just fill" the void spaces between the coarse particles of the skeleton. During undrained cyclic loading, paste rock typically exhibited a cumulative decrease in effective stress along with a progressive degradation of shear stiff-ness. The material generally displayed a higher tendency for strain development under cyclic loading when compared with rock-only and tailings-only specimens subjected to similar consolidation and cyclic loading conditions. However, no strain-softening or loss of shear strength was observed, suggesting that the material is unlikely to experience flow failure under undrained cyclic loading. The cyclic shear resistance was relatively insensitive to the initial effective confining pres-sure (σ' 3c) for the tested stress levels of σ'3c < 400 kPa.

Neth V.W.,EBA Engineering Consultants Ltd.
International Conference and Exhibition on Performance of Ships and Structures in Ice 2010, ICETECH 2010 | Year: 2010

The objective of this drilling program was to extract sediment cores while operating on a floating ice platform at a crater lake in Siberia during the 2008/2009 winter season. The lake, 12 km in diameter and 175 m deep, was formed as a result of a meteoroid impact 3.6 million years ago. The lake is ice covered nine months of the year. Ice engineering work involved the planning, surveying and monitoring of a 7.5 km long ice road and the construction and monitoring of an ice platform in the middle of the lake. The planning and logistic challenges to execute a project at an extremely remote location in Eastern Russia will be presented. Copyright ©2010 Icetech 10. All rights reserved.

Czarnecki B.,EBA Engineering Consultants Ltd. | Day R.L.,University of Calgary
Concrete under Severe Conditions: Environment and Loading - Proceedings of the 6th International Conference on Concrete under Severe Conditions, CONSEC'10 | Year: 2010

By definition, High Performance Concrete (HPC) contains one or more Supplementary Cementitious Materials (SCM) and hydraulic cement, has a low w/cm ratio, usually contains a superplasticizer, and almost invariably contains silica fume. The performance characteristics include long service life, dimensional stability, ease of placement, and load carrying capacity. In a majority of project specifications for HPC, the use of silica fume is made a requirement. The focus of this study was to determine if high quality/high performance concrete can be produced using available sources of aggregate and fly ash, without silica fume. The study shows that both fly ash concrete and silica fume concrete can satisfy high performance expectations and produce an extended service life. The impact of the quality of aggregates and SCMs as well as the consistency of commercially produced concrete mixes on the performance of concrete are assessed. © 2010 Taylor & Francis Group, London.

Barua U.,EBA Engineering Consultants Ltd. | Azad A.K.,University of Calgary | Tay R.,University of Calgary
Transportation Research Record | Year: 2010

Intersections are recognized as the most hazardous locations on roads since conflict possibilities are high at intersections and often result in a high frequency of fatal crashes. A significant share of fatal crashes in Canada occur at intersections on rural undivided highways. Nevertheless, few studies have examined the factors contributing to the fatality risk of intersection crashes in Canada. In this study, a logistic regression model was applied to a sample of crash data at intersections on the rural undivided highways of Alberta, Canada, to investigate 18 factors and 71 variables. Of the significant factors, the major ones affecting the likelihood of fatality are the type of intersection, horizontal and vertical alignment of the highway at the intersection, signalization at the intersection, type of collision, impairment of drivers, and age of drivers involved in crashes. The fatality risk of intersection crashes tends to increase when crashes occur at offset intersections or at cross or T-intersections on horizontal curves. The likelihood of fatality tends to increase if the intersection is on a sag curve or at a constant grade. However, signalization at intersections tends to reduce the likelihood of fatality. Pedestrian-involved collisions, head-on collisions, right-angle collisions, and run-off-road collisions that involve hitting a fixed object and overturning of vehicles are associated with higher fatality risk. An intersection crash also tends to have a higher likelihood of fatality when it involves an older driver (>70 years) or impaired (by alcohol or drugs) or fatigued drivers.

Tay R.,La Trobe University | Churchill A.,EBA Engineering Consultants Ltd | De Barros A.G.,University of Calgary
Accident Analysis and Prevention | Year: 2011

Despite their growing popularity in North America, little research has been conducted on understanding the effects of roadside memorials on drivers' behaviour. In this study, we examined the short-term effects of roadside memorials on traffic speed and headways on a high speed intercity freeway as well as its long-term effect on traffic speed on a high speed urban freeway. Our study found that the placement of roadside memorials did not have any significant effect on traffic speeds or headways, either in the short or long term. Therefore, concerns about the negative effects on driver behaviour were not supported by this research, at least with regards to speeding and following too closely. However, no positive effects on safety were found either. © 2010 Elsevier Ltd.

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