2017

Permanent URI for this collectionhttps://hdl.handle.net/1807/75482

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  • ItemOpen Access
    Developing a Plastic Hinge Model for RC Beams prone to Progressive Collapse
    (Canadian Science Publishing, 2017-12-14) Rouhani, Farzad; Lin, Lan; Galal, Khaled
    It is known that building structures would undergo nonlinearity during progressive collapse. Given this, modelling the nonlinear behaviour of structural members is critical for assessing their resistance. The objective of this study is to develop the nonlinear modelling parameters of RC beams for the progressive collapse analysis. To achieve this, three types of RC moment-resisting buildings located in high, moderate and low seismic zones in Canada are designed. Afterward, nonlinear pushdown analyses are conducted on 27 three-dimensional finite element models using ABAQUS for the case that one column on the ground level is removed. Based on the analysis results, an idealized moment-rotation curve for modelling the plastic hinge in beams with different ductility is proposed. In comparison with the 2013 GSA modelling parameters, smaller chord rotations are observed from the detailed finite element analysis.
  • ItemOpen Access
    Investigation of Alternative Ways for Recycling Waste Foundry Sand: An Extensive Review to Present Benefits
    (Canadian Science Publishing, 2017-11-26) Gedik, Abdul Gazi; Lav, Abdullah Hilmi; Lav, Musaffa Ayşen
    Foundry sand, an indispensable component of the metal casting process, is discarded after a number of metal casting operations. Since virgin sand is required for the new processes, and the spent foundry sand is treated as waste, a huge amount of discarded sand is either stockpiled or dumped into landfills. This results in a wide scale consumption of natural resources despite the fact that this "waste" can be recycled as a viable resource in various engineering processes. To this end, this study represents a detailed investigation into the possible uses for waste foundry sand. Obtained results concluded that this material can best be utilized in highway and hydraulic barrier construction, as well as low strength concrete production. Thus, the recycling of waste foundry sand results in the conservation and saving of natural and financial resources.
  • ItemOpen Access
    Rheological Characterization of Asphalt Binders Treated with Bio Sealants for Pavements Preservation
    (Canadian Science Publishing, 2017-09-27) Ghosh, Debaroti; Turos, Mugurel; Johnson, Ed; Marasteanu, Mihai M
    Pavement preservation is playing an increasingly significant role in maintaining our aged pavement infrastructure under severe budget constraints. One important component is the use of surface treatments based on application of sealants. Recently, a number of new products, called bio sealants, have been used to treat aging pavement surfaces. The objective of this study is to investigate rheological properties of the binders treated with these materials to understand the mechanism by which they may improve pavement performance. One plain asphalt binder and four types of sealants, two oil-based sealants, one water-based sealant and one traditional emulsion were used in the experimental work. The results obtained using a dynamic shear rheometer and a bending beam rheometer were used to determine the changes in rheological properties and the change in performance grade. It was observed that the oil-based sealants have a significant softening effect of the control binder compared to the water-based sealants. The transverse cracking histories from field investigation were used to verify the laboratory findings.
  • ItemOpen Access
    Investigation of Significant Inputs for Pavement Rehabilitation Design in the Pavement M-E
    (Canadian Science Publishing, 2017-12-22) Harsini, Iman; Haider, Syed Waqar; Brink, Wouter C; Buch, Neeraj; Chatti, Karim
    The Pavement-ME can design different flexible or rigid pavements rehabilitation scenarios. A set of quantitative and qualitative input variables are considered to characterize the new and existing pavement layers and predict the damage accumulation in these layers. To evaluate the impact of the inputs on the predicted performance for the rehabilitation options, sequential analyses were performed to assess the main and interactive effects of each input. Continuous responses surface models for interactive effects were obtained using Artificial Neural Network (ANN). Furthermore, a normalized sensitivity index was used to quantify the significance of main and interactive effects. The following rehabilitation options were included in this paper: HMA over HMA, HMA over JPCP, HMA over fractured JPCP, and JPCP over JPCP. The results of the study can assist the highway agenciesâ efforts to implementing the Pavement-ME, especially when the most of pavement designs are related to rehabilitation of the existing highways.
  • ItemOpen Access
    DISCRIMINATION BETWEEN A GROUP OF THREE-PARAMETER DISTRIBUTIONS FOR HYDRO METEOROLOGICAL FREQUENCY MODELING
    (Canadian Science Publishing, 2017-12-18) Ba, Ismaila; Ashkar, Fahim
    We recommend methods of discrimination between some three-parameter distributions used in hydro-meteorological frequency modeling. Discriminations are between model pairs belonging to the group {generalized extreme value (GEV), Pearson Type III (P3), generalized logistic (GLO)}. To assess the fit of these distributions to data, the Akaike information criterion (AIC), Bayesian information criterion (BIC), and/or goodness-of-fit measures are commonly employed. However, it is difficult to estimate the discrimination power and bias of these methods when used with three-parameter distributions. Consequently, we propose two alternative tools and assess their performance. Both tools are based on a sample transformation to normality followed by applying a powerful statistic for testing normality, such as the Shapiro-Wilk or the probability plot correlation coefficient statistic. While arriving at recommendations for discriminating between the (GEV, GLO) and (P3, GLO) pairs of models, we show that the discrimination power between the P3 and GEV distributions can be rather low.
  • ItemOpen Access
    Wind-induced shear and torsion in low-rise and medium-rise buildings: Provisions of National Building Code of Canada 2015
    (Canadian Science Publishing, 2017-12-16) Nguyen, Thai Son; Stathopoulos, Ted; Tirca, Lucia
    This paper discusses the shear and torsion induced in low-rise and medium-rise buildings, according to wind load specifications provided in NBCC 2015. Results from experimental studies, carried out in wind tunnels were compared with corresponding NBCC 2015 provisions under different upstream roughness conditions. These comparisons demonstrated notable discrepancies for the case of torsion in low-rise buildings. Further, comparisons between the wind load specifications given in NBCC 2015 and ASCE/SEI 7-10 standard were carried out. Following both sets of provisions, wind-induced shear and torsion were computed and compared for five low-rise and medium-rise buildings with the same horizontal dimensions but different heights. Emphasis was directed towards the cases that create maximum shear forces and/or maximum torsions in order to reflect critical design conditions. For low-rise buildings, the ASCE/SEI-7-10 and NBCC-2015 yield similar shear coefficients but quite different torsional coefficients; while for medium-rise buildings, clear agreement was found, for both shear and torsion. The diversity of the results is discussed and some suggestions for improvement of code provisions are made. A definition for medium-rise buildings was provided
  • ItemOpen Access
    CONSTRUCTION PRODUCTIVITY FUZZY KNOWLEDGE BASE MANAGEMENT SYSTEM
    (Canadian Science Publishing, 2017-12-22) Elwakil, Emad; Zayed, Tarek
    Construction companies need a Knowledge Management system in order to collate, share and ultimately apply this knowledge in various projects. One of the most important elements that determine the time estimates of any construction project is Productivity. Such projects have a predilection towards uncertainty and therefore require new generation of prediction models that utilizes available historical data. The research presented in this paper develops, using Fuzzy approach, a knowledge base to analyze, extract and infer any underlying patterns of the data sets to predict the duration and productivity of a construction process. A six-step protocol has been followed to create this model: (1) determine which factors affect productivity; (2) select those factors which are critical; (3) build the Fuzzy sets; (4) generate the Fuzzy rules and models; (5) develop the Fuzzy knowledge base; and (6) validate the efficacy and function of these models in predicting the productivity construction process. The Fuzzy knowledge base was validated and verified using a case study and the results were satisfactory with 92.00 % mean validity. In conclusion, the developed models/system demonstrated the ability of a knowledge base management to predict the patterns and productivity of different construction operations
  • ItemOpen Access
    Gene-Expression Programming to Predict Manning’s n in Meandering Flows
    (Canadian Science Publishing, 2017-11-29) Pradhan, Arpan; Khatua, Kishanjit K
    Accurate prediction of Manning’s roughness coefficient is essential for the computation of conveyance capacity in open channels. There are various factors affecting the roughness coefficient in a meandering compound channel and not just the bed material. The factors, geometric as well as hydraulic, are investigated and incorporated in the prediction of Manning’s n. In this study, a new and accurate technique, gene-expression programming (GEP) is used to estimate Manning’s n. The estimated value of Manning’s n is used in the evaluation of the conveyance capacity of meandering compound channels. Existing methods on conveyance estimation are assessed in order to carry out a comparison between them and the proposed GEP model. Results show that the discharge capacity computed by the new model provides far better results than the traditional models. The developed GEP model is validated with three individual sections of a natural river, signifying that the model can be applied to field study of rivers, within the stated range of parameters.
  • ItemOpen Access
    Shear deformable hybrid finite-element formulation for buckling analysis of composite columns
    (Canadian Science Publishing, 2017-11-29) Niki, Vida; Erkmen, Emre
    The objective of this study to develop a shear deformable hybrid finite element formulation for the flexural buckling analysis of fiber-reinforced laminate composite columns with doubly symmetric cross-sections. The hybrid finite element formulation is developed by using the Hellinger-Reissner functional which is obtained by introducing the conditions of compatibility as auxiliary conditions to the potential energy functional. The shear deformation effects due to bending are included by equilibrating shear stress. In comparison to the displacement-based formulations the current hybrid formulation has the advantage of incorporating the shear deformation effects easily by using the strain energy of the shear stress field without modifying the basic kinematic assumptions of the beam theory. The agreement with Engesser formulation for flexural buckling analysis of columns with shear-weak cross-sections shows the applicability and accuracy of the current hybrid finite element method for composite structural elements. The applicability of the developed method herein to sandwich and built-up columns are also illustrated.
  • ItemOpen Access
    Near-Field Explosion Effects on Reinforced Concrete Columns: An Experimental Investigation
    (Canadian Science Publishing, 2017-12-14) Braimah, Abass; Siba, Farouk
    Explosion effects on structures have been an area of active research over the past decades. This is due to the increasing number of terroristsâ action against infrastructures. Although significant amount of work is continuing on the effects of explosions on infrastructures, experimental work involving live explosion testing is limited. Moreover experimental testing of reinforced concrete (RC) columns subjected to near-field explosions is scant. This paper presents results of an experimental program designed to investigate the effects of near-field explosions on RC columns with different tie spacing and at different scaled distances. The results show that the response of columns is strongly dependent on scaled distance. As the scaled distance increased the severity of damage reduced seismic columns showed better response. The effect of axial loading was also observed to increase the level of damage on reinforced concrete columns at the axial load level and blast loads considered in the test program.
  • ItemOpen Access
    Motivation and Implementation of Traffic Management Strategies to Reduce Motor Vehicle Emissions in Canadian Cities
    (Canadian Science Publishing, 2017-12-09) Bigazzi, Alexander York; Mohamed, Amr
    There is a pressing need to reduce pollution emissions from transportation and consequent negative effects on air quality, public health, and the global climate. Diverse traffic management strategies have been proposed and undertaken with primary or secondary goals of reducing motor vehicle emissions. The objective of this paper is to investigate the motivation and implementation of traffic management strategies to reduce motor vehicle emissions, with a focus on moderate-scale local and regional strategies that are broadly applicable. Public documents from 44 local, regional, and provincial government entities across Canada were reviewed for information regarding the implementation of 22 traffic management strategies. Results show that different levels of government are involved in the implementation of different types of strategies, and with a different mix of traffic, safety, and environmental motivations. Regional governments more frequently cite environmental motivations and appear to be most interested in the two strategies with the strongest empirical evidence of air quality benefits: area road pricing and low emission zones. Strengthening regional transportation planning and better integrating it with municipal and provincial planning could potentially increase the implementation of effective sustainable traffic management strategies in Canada. Additional opportunities exist through emphasizing the potential environmental co-benefits of strategies such as road pricing, speed management, and traffic signal and intersection control improvements
  • ItemOpen Access
    Flexible pavement damage during spring thaw: a field study using the falling weight deflectometer
    (Canadian Science Publishing, 2017-11-30) Bilodeau, Jean-Pascal; Doré, Guy
    Spring thaw creates critical performance conditions for pavement networks. The increase of water content in the pavement environment is significant during spring thaw. Combined with poor drainage conditions, materials condition variations are triggering factors that accentuate the effect of heavy vehicle loading on pavement response and damage. Two experimental pavement sections were monitored in 2014 and 2015 for temperature and deflections. the section with the lowest structural capacity was found to be more sensitive to thaw weakening. Fatigue damage calculated for this section was found to be 31 % higher than the section with the highest structural capacity. Moreover, it was shown that a load reduction in the range of 20 % can decrease the total yearly damage by about 7 to 10 % for the considered test sections. In general, fatigue damage was found to increase from spring onset to the warmest conditions of the yearly cycle, in July.
  • ItemOpen Access
    Identification of most significant factors for modeling deterioration of sewer pipes
    (Canadian Science Publishing, 2017-11-17) El-Housni, Hind; Ouellet, Maxim; Duchesne, Sophie
    Existing methods used to identify the important factors that can improve predicting structural deterioration of sewer pipes rarely take into account the interactions and correlations among them. Here we present a standardized method that combines use of the Cox model and likelihood ratio test, and overcomes these limitations of previously employed methods. This combined method is applied to the pipes of two Canadian sewer systems, and its results are compared to the results of two simpler methods for the identification of the factors that significantly influence sewer pipe deterioration. The three methods identified pipe age as the principal factor driving the structural deterioration of sewer pipes. However, slight differences between the methods for other potential influential factors (material, slope and diameter) showed that accounting for the interactions and correlations among factors, as is possible with the proposed method, is crucial to identifying the factors having a significant impact on pipe deterioration.
  • ItemOpen Access
    Strength behavior of plain cement concrete subjected to true-triaxial compression
    (Canadian Science Publishing, 2017-10-21) Rukhaiyar, Saurav; Sajwan, Gaurav; Samadhiya, Narendra Kumar
    True-triaxial compression test was conducted on 100 mm x 100 mm x 100 mm cubical sample of plain cement concrete using the true-triaxial testing machine. A total of 30 tests were conducted on two mix of concrete having characteristic strengths of 24.39 MPa and 34.67 MPa. The minor and intermediate principal stresses were varied from 2.5 MPa to 10 MPa and 2.5 MPa to 30 MPa respectively. The samples were loaded till failure under the stress rate of 1 MPa/min. The failure mode and direction of fracture planes were observed carefully. It was observed that the ratio of intermediate and minor principal stress had an incremental effect on the strength of the concrete. The results obtained from our experimental study as well as the true-triaxial compression test data published in literature has been used to conduct a quantitative evaluation of three commonly used failure criteria presented for the concrete. The three failure criteria considered are Drucker-Prager (DP) criterion, Bresler-Pester (BP) criterion and Hsieh-Ting-Chen (HTC) criterion. It was observed that for the normal strength concrete, the HTC criterion predicts the strength with least error while for the high strength concrete, the DP criterion have a better prediction. Overall the DP and BP criterion underestimates the strength while the HTC criterion overestimates
  • ItemOpen Access
    Concrete in Canada: Fifty Years of Progress – Present Concerns
    (Canadian Science Publishing, 2017-02-11) Aïtcin, Pierre-Claude; Wilson, William; Mindess, Sidney
    Over the past 50 years, concrete in Canada has evolved from a simple robust material to a complex composite with impressive improvements in the material properties. Due to the development of water reducers and silica fume, the performance of concrete has improved from the conventional 30 MPa concrete before the CN Tower (1973) to the ultra-high strength 200 MPa concrete used in the Passerelle de Sherbrooke (1998). This paper retraces this evolution of concrete with a focus on both the technical improvements and the important structures built with these technologies. Recent progress in blended cements and poly-carboxylate ether superplasticizers is also presented, along with the concerns and current challenges to ensure an optimized and safe use of these new concrete admixtures.
  • ItemOpen Access
    Estimate of void fraction and air entrainment flux in hydraulic jump using Froude number
    (Canadian Science Publishing, 2017-01-09) Wang, Hang; Chanson, Hubert
    Hydraulic jumps are induced in hydraulic facilities for the purposes of energy dissipation or flow aeration. Presently there is no means for a simple estimate of void fraction distribution and air entrainment flux, without detailed physical modelling. This paper presents a semi-theoretical model to simulate the void fraction and velocity distributions in hydraulic jumps characterised by partially-developed inflow conditions. Relationships were established between the inflow Froude number, jump roller length and key parameters that determine the full expression of void fraction and velocity profiles. The proposed model enables accurate prediction of void fraction, longitudinal velocity and air flux using the inflow Froude number. The results indicated considerable air flux contribution of free-surface aeration, in addition to the singular air entrainment at the jump toe, for moderate to large Froude numbers. A Froude number between 8 and 9 tended to achieve highest aeration rate with maximum total air flux in the roller.
  • ItemOpen Access
    Estimate of void fraction and air entrainment flux in hydraulic jump using Froude number
    (Canadian Science Publishing, 2017-01-09) Wang, Hang; Chanson, Hubert
    Hydraulic jumps are induced in hydraulic facilities for the purposes of energy dissipation or flow aeration. Presently there is no means for a simple estimate of void fraction distribution and air entrainment flux, without detailed physical modelling. This paper presents a semi-theoretical model to simulate the void fraction and velocity distributions in hydraulic jumps characterised by partially-developed inflow conditions. Relationships were established between the inflow Froude number, jump roller length and key parameters that determine the full expression of void fraction and velocity profiles. The proposed model enables accurate prediction of void fraction, longitudinal velocity and air flux using the inflow Froude number. The results indicated considerable air flux contribution of free-surface aeration, in addition to the singular air entrainment at the jump toe, for moderate to large Froude numbers. A Froude number between 8 and 9 tended to achieve highest aeration rate with maximum total air flux in the roller.
  • ItemOpen Access
    Environmental Risk Factors for Bacteriological Contamination in Rural Drinking Water Wells in Samson Cree Nation
    (Canadian Science Publishing, 2017-10-24) Mah, Fraser; Hnidan, Travis; Davies, Evan; Ulrich, Ania
    Bacteriological contamination of drinking water wells poses a challenge to many rural areas of First Nations communities in Alberta that rely on wells as the primary drinking water source for large proportions of their populations. Here we reviewed available historical data for the Samson Cree Nation near Maskwacis, Alberta (formerly Hobbema), to identify linkages between various environmental/historical factors and the risk of contamination by Escherichia coli and total coliform bacteria. Increased bacterial counts were found to be associated with a peak in total precipitation and surface water flow following a two to four month lag period. Wells installed by contractors operating at an earlier period in time were also found to be at greater risk than more recent installations. These findings can be used to characterize better the risk of contamination, which will assist in tailoring remedial actions to address chronic or recurring bacteriological presence in wells.
  • ItemOpen Access
    Statistical description of morphological characteristics of bedforms in seepage affected alluvial channels
    (Canadian Science Publishing, 2017-09-25) Patel, Mahesh; Majumder, Shantanaba; Kumar, Bimlesh
    In this study, experiments were performed in a curvilinear cross-sectional threshold alluvial channel with no seepage and with seepage conditions in order to understand the influence of downward seepage in an alluvial channel. We observed that stable channel during no seepage condition started to reach in transporting stage with downward seepage. Increased value of Shields stress was observed after the application of seepage. In addition, this study deals with the effect of downward seepage on the evolution of alluvial bedforms. In this regard, multi-temporal bed elevation profiles were collected along the test section of channel, which are used to characterize migrating bedforms. Results reveal greater fluctuations and variability on the channel bed under the influence of increased seepage discharge. Slope of the power spectral density with wavenumber was significantly increased with an increment in seepage percentage, showing more inhomogeneous arrangement of bedforms and larger roughness over the channel boundary.
  • ItemOpen Access
    A Hybrid Method for Short-term Freeway Travel Time Prediction Based on Wavelet Neural Network and Markov Chain
    (Canadian Science Publishing, 2017-09-12) Yang, Hang; Zou, Yajie; Wang, Zhongyu; Wu, Bing
    Short-term travel time prediction is an essential input to Intelligent Transportation Systems (ITS). Timely and accurate traffic forecasting is necessary for Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS). Despite several short-term travel time prediction approaches have been proposed in the past decade, especially for hybrid models which consist of machine learning models and statistical models, few studies focus on the over-fitting problem brought by hybrid models. The over-fitting problem deteriorates the prediction accuracy especially during peak hours. This paper proposes a hybrid model which embraces Wavelet Neural Network, Markov Chain and the volatility model (WNN-MAR-VOA) for short-term travel time prediction in a freeway system. The purpose of this paper is to provide deeper insights into underlining dynamic traffic patterns and to improve the prediction accuracy and robustness. This method takes periodical analysis, error correction and noise extraction into consideration and improve the forecasting performance in peak hours. The proposed methodology predicts travel time by decomposing travel time data into three components: a periodic trend presented by a modified Wavelet Neural Network (WNN), a residual part modeled by Markov Chain, and the volatility part estimated by the modified generalized autoregressive conditional heteroscedasticity (GJR-GARCH) model. Forecasting performance is investigated with freeway travel time data from Houston, Texas and examined by three measures: mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE). The results show that the travel times predicted by the WNN-MAR-VOA method are robust and accurate. Meanwhile, the proposed method is able to capture the underlying periodic characteristics and volatility nature of travel time data