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Sharif M.,Jamia Millia Islamia University | Burn D.H.,University of Waterloo | Hofbauer K.M.,University of Waterloo | Hofbauer K.M.,McCormick Rankin Corporation
Water Resources Management | Year: 2013

This paper evaluates the impact of climate change, as projected by two Global Climate Models (GCMs) on the occurrence of extreme precipitation events in the Upper Thames River Basin in the Canadian province of Ontario. The modelling approach presented herein involves a two-stage process of generating daily weather data followed by disaggregation to an hourly time step of select variables for some events. Monthly change fields for three weather variables (maximum temperature, minimum temperature, and precipitation) were obtained from the output of two GCMs. The historical data set is modified by applying change fields to the weather variables simultaneously and then using this as the driving data set for an improved K-nearest neighbour weather-generating model. Weather sequences representative of climatic conditions in 2050 were simulated. Disaggregation of precipitation data is carried out using a new method that is a hybrid key site approach. A distinct practical advantage of the approach presented here is that extreme wet and dry spells are simulated, which is crucial for evaluation of effective flood and drought management policies for the basin. © 2012 Springer Science+Business Media Dordrecht.

Wu W.,University of Mississippi | Altinakar M.S.,University of Mississippi | Song C.R.,University of Ottawa | Al-Riffai M.,Building and Infrastructure Testing Laboratory Ltd. | And 40 more authors.
Journal of Hydraulic Engineering | Year: 2011

Embankment breaching processes are very complex and involve mixed-regime free-surface flow with overfalls and hydraulic jumps, pressurized pipe flow, strong vertical and lateral erosion, discrete mass failure, and headcut migration. The failure mode and mechanism are affected by upstream and downstream water conditions, embankment configurations, and soil properties and state. Great progress has been made to investigate embankment breaching processes through laboratory and field experiments and real-world case studies. However, most laboratory experiments were for smallscale homogeneous embankments, only a few outdoor experiments were conducted at large scales (up to several meters in height) and/or were of composite construction, and only limited data sets for historical embankment failures were sufficiently documented. A number of parametric, simplified physically-based, and detailed multidimensional physically-based embankment breach models have been established in the past decades, but prediction with these models involves significant uncertainties. The biggest limitation of the existing breach models is quantifying erosion rates or erodibility of cohesive soils and sediment entrainment under embankment break/breaching flows. It is important to conduct more large-scale laboratory experiments and field case studies to improve existing embankment breach models or develop new ones. These models should also be enhanced by incorporating better physical insights, by using more efficient computational technologies, and integrating them into more robust flood forecasting and risk assessment systems with comprehensive relevant databases © ASCE.

Bowser M.,McCormick Rankin Corporation | Walbridge S.,University of Waterloo | West J.,University of Waterloo
Transportation Research Record | Year: 2012

To enable a portable composite bridge, a shear connection between steel plate girders and precast concrete deck panels, which would allow these two components to be fastened and unfastened, proposed. In the system, points of shear connection would be spaced at 3 m on center along the length of the girder. Finite element analysis was employed to compare the performance of the proposed composite system to a conventional composite girder with ductile shear studs. A nonlinear analysis was performed, and the proposed composite system was seen to demonstrate a response comparable to that of a composite girder with conventional shear studs. The model was verified for its capability to capture the possible effects of flange buckling, web buckling, and lateral torsional buckling of the steel plate girder. It was then confirmed that these failure modes did not influence the performance of the proposed portable composite bridge system for the investigated bridge configuration. A parametric study also was performed: the effects of shear connection stiffness and spacing on the behavior of the composite girder were investigated. In general, the investigated variations of these parameters had a significant influence on the girder stiffness but only a limited impact on the ultimate strength.

Choi H.,McCormick Rankin Corporation | West J.S.,University of Waterloo | Soudki K.A.,University of Waterloo
Proceedings, Annual Conference - Canadian Society for Civil Engineering | Year: 2011

An extensive experimental and analytical investigation on concrete beams strengthened with partially bonded FRP showed that the deformability in the partially bonded beams was greatly improved, and the loss of the ultimate load carrying capacity was minimized, compared to fully bonded beams. A parametric study was performed to investigate the effect of the main parameters on the behaviour of the partially bonded beams and to derive design guidelines for the effective use of the partially bonded FRP strengthening system. The parametric study showed that a FRP strengthened beam, that has a FRP area less than the balanced area of FRP, has high potential to improve the deformability, as the unbonded length increases. This balanced FRP area is a function of the beam configuration, including the concrete strength, the area of the steel reinforcement, and the level of prestress in the FRP. Based on the parametric study, design charts and a design procedure were proposed to determine an appropriate unbonded length as a function of the beam configuration.

Choi H.T.,McCormick Rankin Corporation | West J.S.,University of Waterloo | Soudki K.A.,University of Waterloo
Construction and Building Materials | Year: 2011

A partially bonded strengthening approach for reinforced concrete (RC) beams utilizing near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) bars was investigated with the specific objective of improving deformability. A total of six RC T-beams strengthened with NSM CFRP bars of various unbonded lengths were tested. Test results showed a decrease of the stiffness at the post-yield stage of the load-deflection response in the partially bonded beams. This is caused by the delayed increase of the FRP strain within the unbonded length. As a result the beam deformability was increased as the unbonded length increased at the same applied load. Internal slip of the FRP bar and gradual concrete failure were observed near the ultimate state, which caused a complicate nonlinear behavior of the beams. An analytical model is proposed to address the complete beam behavior including the effect of slip of FRP reinforcement and gradual concrete crushing. This model was developed based on the compatibility of deformation of the partially bonded system and was able to represent the ultimate behavior of the beams well. © 2010 Elsevier Ltd. All rights reserved.

Choi H.T.,McCormick Rankin Corporation | West J.S.,University of Waterloo | Soudki K.A.,University of Waterloo
Journal of Composites for Construction | Year: 2011

The flexural behavior of RC T-beams strengthened with prestressed near-surface-mounted (NSM) carbon fiber-reinforced-polymer (CFRP) reinforcement was investigated. The specific objective was to study the effect of partial unbonding of the CFRP reinforcement on the beam flexural behavior to increase the deformability. A total of eight RC T-beams were tested under four-point monotonic loading. The main variables were the level of prestressing force in the CFRP bars and the unbonded length at the midspan of the beam. The test results showed that all of the prestressed strengthened beams effectively improved the ultimate load-carrying capacity and the serviceability performance compared to the unstrengthened beam. The partially bonded prestressed beams exhibited an enhancement of the deformability compared to the fully bonded beams while minimizing the reduction of the load-carrying capacity. Partial unbonding was more effective to improve the deformability at higher levels of prestressing force. The general behavior of the partially bonded beams was reasonably well predicted by an analytical model developed previously by the writers. © 2011 ASCE.

Jacob C.,McCormick Rankin Corporation | Abdulhai B.,University of Toronto
Transportation Research Part A: Policy and Practice | Year: 2010

Urban traffic corridors are often controlled by more than one agency. Typically in North America, a state of provincial transportation department controls freeways while another agency at the municipal or city level controls the nearby arterials. While the different segments of the corridor fall under different jurisdictions, traffic and users know no boundaries and expect seamless service. Common lack of coordination amongst those authorities due to lack of means for information exchange and/or possible bureaucratic 'institutional grid-lock' could hinder the full potential of technically-possible integrated control. Such institutional gridlock and related lack of timely coordination amongst the different agencies involved can have a direct impact on traffic gridlock. One potential solution to this problem is through integrated automatic control under intelligent transportation systems (ITS). Advancements in ITS and communication technology have the potential to considerably reduce delay and congestion through an array of network-wide traffic control and management strategies that can seamlessly cross-jurisdictional boundaries. Perhaps two of the most promising such control tools for freeway corridors are traffic-responsive ramp metering and/or dynamic traffic diversion possibly using variable message signs (VMS). Technically, the use of these control methods separately might limit their potential usefulness. Therefore, integrated corridor control using ramp metering and VMS diversion simultaneously might be synergetic and beneficial. Motivated by the above problem and potential solution approach, the aim of the research presented in this paper is to develop a self-learning adaptive integrated freeway-arterial corridor control for both recurring and non-recurring congestion. The paper introduces the use of reinforcement learning, an Artificial Intelligence method for machine learning, to provide optimal control using ramp metering and VMS routing in an integrated agent for a freeway-arterial corridor. Reinforcement learning is an approach whereby the control agent directly learns optimal strategies via feedback reward signals from its environment. A simple but powerful reinforcement learning method known as Q-learning is used. Results from an elaborate simulation study on a key corridor in Toronto are very encouraging and discussed in the paper. © 2009 Elsevier Ltd. All rights reserved.

Saiedi R.,Queen's University | Saiedi R.,McCormick Rankin Corporation | Fam A.,Queen's University | Green M.F.,Queen's University
Journal of Composites for Construction | Year: 2011

This paper investigates the behavior of concrete beams prestressed with carbon fiber-reinforced polymer (CFRP) rods under high-cycle fatigue at low temperature. Seven precast T-beams were tested, including five beams prestressed to various levels with the CFRP rods and two beams with conventional steel strands. All beams had a history of sustained loading. Some beams were directly loaded monotonically to failure as control specimens. Other beams were subjected to three million cycles of flexural loading, either at room temperature or at -28°, prior to being monotonically loaded to failure at the same temperature. All CFRP-prestressed beams survived the three million cycles, whereas the steel-prestressed beam did not. It was shown, however, that the bond between CFRP rods and concrete could be weakened because of cyclic loading, low temperature during loading, or high prestress level. This resulted in a premature bond failure at 70 to 90% of the full flexural strength in subsequent monotonic loading. Also, stiffness and camber gradually decreased during cyclic loading. © 2011 American Society of Civil Engineers.

Cerullo D.,McCormick Rankin Corporation | Cerullo D.,Ryerson University | Sennah K.,Ryerson University | Azimi H.,Ryerson University | And 3 more authors.
Journal of Composites for Construction | Year: 2013

A bridge was damaged when a dump truck violated the height clearance limitation on Highway 401 in Ontario, Canada. The collision caused extensive damage to the AASHTO Type-III precast/prestressed bridge girders, which led to the closure of the two-lane bridge. Crack mapping showed extensive torsion-shear cracks between the girder quarter points, horizontal crack at the flange-web junctions, and spalled concrete at point of impact. Preliminary elastic testing on the girder established that the flexural capacity of the girder had not been significantly affected. As such, flexural strengthening was not necessary. Crack patterns and severity, followed by analysis, have shown that the girder is deficient in shear capacity. Therefore, the girder was strengthened for shear throughout its entire length using carbon fiber-reinforced polymer (CFRP) sheets. This paper presents a summary of the design and detailing of the elastic behavior test conducted before repair, the girder repair methodology, and results from proof load testing of the repaired girder. It was shown that the rehabilitated girder could sustain flexural live load demand. A field application was also carried out using the same rehabilitation technique on another impact-damaged bridge in Ontario. It was viewed as a major budget-saving project compared to the girder replacement alternative, because of the speed of rehabilitation and the minor traffic disruptions. © 2013 American Society of Civil Engineers.

Orendorff B.,McCormick Rankin Corporation | Rennie C.D.,University of Ottawa | Nistor I.,University of Ottawa
Journal of Hydro-Environment Research | Year: 2011

Particle tracking velocimetry was used to determine for the first time the surface velocities upstream, downstream, and through experimental embankment dam breach channels at all stages of breach development. A series of experimental tests was performed, which used varying initial breach geometry. The measurements were made using Styrofoam surface tracking particles and three different video camera angles to obtain 3-dimensional velocity measurements, which were calculated using ArcGIS. Space-time contour maps of velocity were then interpolated for each of the breach scenarios. A maximum surface flow velocity of 2.1 m/s, corresponding to 21 m/s at prototype scale, was measured at the downstream end of the breach channel near the time to peak for the breach outflow. The surface velocities were also converted to average velocities and used in conjunction with breach flow measurements to determine the depth of flow through the breach channel and to make estimates of the sub-aqueous breach geometry. Estimates of flow depth through the breach were used to compare measured outflow results with those determined analytically using the broad-crested weir equation. © 2011 International Association of Hydro-environment Engineering and Research, Asia Pacific Division.

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