MMM Group Ltd.

Kitchener, Canada

MMM Group Ltd.

Kitchener, Canada
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Bowser M.,MMM Group Ltd | Stephenson J.,Region of Waterloo
Structural Engineering International: Journal of the International Association for Bridge and Structural Engineering (IABSE) | Year: 2017

In cold climates, special consideration needs to be given to the design and construction of segmental posttensioned concrete girder bridges. This article presents the special considerations that enabled winter construction of the Fairway Road/Grand River Bridge in Canada at a location where temperatures commonly drop below -20°C. The four-span crossing is a high-level, variable depth, post-Tensioned, cast-in-place, twin box-girder segmental bridge, 237 m in length with a main span of 95 m over the Grand River. During the winter months, the form traveler was enclosed and heated to protect the cast-in-place concrete. Cold weather concrete protection to enable winter construction is common practice in Canada, but to enable segmental post-Tensioned construction during the winter months a method to protect the tendons after stressing was necessary. Standard specifications require tendons to be grouted within 14 days of tensioning. However, posttensioning grout typically requires a minimum temperature of 5°C. Therefore, a method of applying a corrosion inhibitor powder was implemented during winter construction to provide temporary protection of the stressed tendons until temperatures permitted the grouting to be completed. This article also presents special design features that include the use of glass fibre reinforced polymer reinforcing and high performance concrete.

Ho E.,MMM Group Ltd | Lukashenko J.,MMM Group Ltd
2011 Conference and Exhibition of the Transportation Association of Canada - Transportation Successes: Let's Build on Them, TAC/ATC 2011 | Year: 2011

There is increasing pressure on bridge designers to minimize joints on bridge decks in order to reduce maintenance and long-term rehabilitation costs. One method of achieving this that is gaining popularity in recent years is the use of concrete link slabs. A concrete link slab is a relatively thin reinforced concrete slab that typically connects simply supported deck spans. It is designed to flex due to girder deflections and also transmit compressive and tensile forces through the deck in conjunction with appropriately designed bearings. This paper will describe available design methodologies and provide an example of its application for a bridge retrofit. Link slabs are currently being installed in new bridge construction, and also used to replace expansion joints in the rehabilitation of existing structures. The applicable use of link slabs in the field is limited by variables such as girder end rotation from applied loads, bridge skew, and girder depth. Link slabs are designed to flex, however excessive deflection causes potential for the development of wide cracks, exposing the interior steel reinforcement to susceptibility of corrosion. The concrete deck is typically composite with the supporting steel or concrete girders, but is debonded in the link slab region to increase the link slab curvature length, resulting in a reduced slab flexure and minimizing cracking. Although flexural cracking cannot be completely eliminated, water ingress into the cracks can be controlled by the following design considerations: limiting deck crack opening width by limiting end girder rotation; application of waterproofing membrane on top of concrete deck; and use of fibrereinforced concrete in the link slab.

Schilleman B.,Stantec Inc. | Gough J.,MMM Group Ltd.
ITE Journal (Institute of Transportation Engineers) | Year: 2012

Sustainable transportation projects are increasingly important as the world population grows, resources shrink, and environmental impacts become more pervasive. Federal, state/provincial, and local rules, programs, and practices are already evolving in response to this emerging issue. ITE members are among the world's leaders in identifying and developing innovative and sustainable transportation practices, and are changing the standards for our industry. More than 480 responses to the survey were received from Australia, Canada, and the United States. The respondents provided a wealth of information in response to a 17-question survey, which encompassed current practices with respect to definitions, performance measures, organizational approaches to sustainability, funding, certification, and other topics.

Samuelson H.W.,Harvard University | Ghorayshi A.,MMM Group Ltd. | Reinhart C.F.,Massachusetts Institute of Technology
2014 ASHRAE/IBPSA-USA Building Simulation Conference | Year: 2014

This paper evaluates the accuracy of 18 design-phase building energy models, used for documentation for LEED Canada certification, and analyzes the effectiveness of simple model calibration steps applied to these models. The calibration steps included inputting actual weather data, adding unregulated loads, revising process loads (often with submetered data), and updating a minimal number of other inputs. In net, the design-phase energy models under-predicted the total measured energy consumption by 36%. Following the above outlined calibration steps, this error was reduced to a net 7% under-prediction. For the monthly Energy Use Intensity (EUI) the coefficient of variation of the root mean square error improved from 45% to 24%. Revising the process loads was particularly important in these cases. This step alone increased the EUI by 32% on average (15% median) in the models. This impact far exceeded that of calibrating the weather data, even in a sensitivity test using extreme weather years. These results suggest that although compliance-type energy models can be poor predictors of actual energy use, practitioners may be able to make initial strides toward calibration with relatively little effort. © 2014 ASHRAE.

Jim G.,MMM Group Ltd.
ITE Journal (Institute of Transportation Engineers) | Year: 2010

Transportation professionals are always looking to make things safer, cleaner and more sustainable. while there is no one single guide to best practices in this area, a look at some of the efforts already uhdertakeh-as well as a look toward the future-may provide the profession with the tools it needs to create a system of best practices that will guide transportation's increasing role in building a sustainable world.

Perry V.,Lafarge | Krisciunas R.,Ontario Ministry of Transportation | Stofko B.,MMM Group Ltd
PCI Journal | Year: 2014

The Mackenzie River bridges are part of the TransCanada Highway realignment near Thunder Bay, ON, Canada. The project consists of twin two-lane bridges, each with three spans, for a total length of 180 m (590 ft). The bridges cross a deep gorge of the Mackenzie River using variable depth, continuous steel plate girders with full-depth precast concrete deck panels that are lightly prestressed and extend the full width of the bridge. Precast concrete approach slabs and 130 precast concrete deck panels (2.99 m [9.6 ft] wide x 14.5 m [47.6 ft] long x 225 mm [9 in.] thick) were connected at transverse joints and attached to the steel girders through shear pockets and haunches using a total of 175 m3 (229 yd3) field-cast ultra-high-performance concrete (UHPC).

Samuelson H.W.,Harvard University | Ghorayshi A.,MMM Group Ltd. | Reinhart C.F.,Massachusetts Institute of Technology
Journal of Building Performance Simulation | Year: 2016

This paper evaluates the accuracy of 18 design-phase building energy models, built according to LEED Canada protocol, and investigates the effectiveness of model calibration steps to improve simulation predictions with respect to measured energy data. These calibration steps, applied in professional practice, included inputting actual weather data, adding unregulated loads, revising plug loads (often with submetered data), and other simple updates. In sum, the design-phase energy models underpredicted the total measured energy consumption by 36%. Following the calibration steps, this error was reduced to a net 7% underprediction. For the monthly energy use intensity (EUI), the coefficient of variation of the root mean square error improved from 45% to 24%. Revising plug loads made the largest impact in these cases. This step increased the EUI by 15% median (32% mean) in the models. This impact far exceeded that of calibrating the weather data, even in a sensitivity test using extreme weather years. © 2014 International Building Performance Simulation Association (IBPSA).

Zhang Q.,University of British Columbia | Alam M.S.,University of British Columbia | Khan S.,MMM Group Ltd | Jiang J.,MMM Group Ltd
Canadian Journal of Civil Engineering | Year: 2016

Performance-based design (PBD) was first introduced in Canadian Highway Bridge Design Code (CHBDC) in 2014. Performance-based design is the design that meets multiple performance criteria under different earthquake hazards. To investigate the impact of changes in CHBDC 2014, a four-span concrete highway bridge is designed and evaluated using force-based design (FBD) and PBD methods as per CHBDC 2014, and FBD method as per CHBDC 2006. By incorporating soil– structure interaction (using p–y curves) nonlinear pushover and dynamic time history analyses are conducted to assess the seismic performance of these bridges. Maximum strains of concrete and reinforcing steel are compared among the three designs to determine their performance levels. It is concluded that PBD (CHBDC 2014) is highly conservative compared to FBD (for both CHBDC 2014 and 2006). For the three-level PBD approach, the design is governed by the criterion of reinforcing steel not yielding under the design earthquake (with 475 years return period). © remains with the author(s) or their institution(s).

Hasaballa M.,University of Manitoba | Mady M.,MMM Group Ltd. | El-Salakawy E.,University of Manitoba
Proceedings of the 4th Asia-Pacific Conference on FRP in Structures, APFIS 2013 | Year: 2013

Implementing the non-corrodible glass fibre-reinforced polymer (GFRP) reinforcement in reinforced concrete (RC) infrastructure is a viable alternative to avoid steel-corrosion problems. However, the behaviour of GFRP bars in tension-compression reversed cycles in RC frame structures has not been well investigated yet. Furthermore, the elastic-linear behaviour of the GFRP reinforcement up to failure makes the ability to dissipate energy of frame structures in seismic loading events questionable. Therefore, this study attempts to partially fulfill this gap by investigating the structural performance and ultimate capacity of concrete beam-column connections reinforced with GFRP bars. In this paper, four full-scale exterior beam-column joint prototypes were constructed and tested under simulated seismic load conditions. Specimens were reinforced with GFRP bars. The test variable is the beam end anchorage (increased column depth, beam stubs and headed bars) of the beam longitudinal bars within the joint. Test results are presented in terms of load-drift ratio relationship, ultimate capacity and mode of failure. The study concluded that using beam stubs or headed bars are viable solution wherever geometric constraints do not allow for deep columns. © 2013 International Institute for FRP in Construction.

Khan S.,MMM Group Ltd | Jiang J.,MMM Group Ltd
Structures Congress 2015 - Proceedings of the 2015 Structures Congress | Year: 2015

Performance based seismic design has emerged as one of the most rational methods to overcome inherent risks and uncertainties in predicting the seismic performance of structures designed by the force based approach. The Vancouver Evergreen Line Rapid Transit Project is a first known rapid transit project in Canada utilizing the multi-level performance-based design approach for the Guideway structures. The proposed Guideway alignment runs through enormously challenging site conditions prone to soil liquefaction causing variable, large-scale lateral spreading. Ground improvements were mostly precluded due to deep liquefiable layers coupled with a stiff crest near the surface, utility proximity and right of way issues. Innovative and robust structural solutions had to be developed to meet the performance criteria. Non-linear structural analyses incorporating soil-pile-structural interactions and directional ground deformations were carried out to confirm structural performance. As per the Project Agreement, the station building structures were designed based on the single-level and force-based design approach of the 2006 British Columbia Building Code, which presented additional challenges for the interface structural elements. This paper provides a summary of the seismic design criteria specified by the PA, seismic design review and approval process, technical challenges faced and innovative design solutions developed to meet the prescribed seismic performance criteria.

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