bluuebunny/crossref_metadata_2025 huggingface dataset:
Tests of frazil collector lines to assist ice cover formation
Authors: Perham Roscoe E.
Published: January 2010

A preliminary investigation was made of the effect of frazil ice on arrays of lines positioned in flowing water under winter conditions. It was found that the lines would provide a stable basis for forming an ice cover on many stream reaches that would normally remain open because of high velocity and shallow depths.Tests were conducted in a refrigerated flume and in small mountain rivers. Flume depths varied from 2 – 22 cm and river depths varied from 33–50 cm. Average flow velocities had a range of 0.08–0.84 m/s in the flume and a range of 0.6–0.8 m/s in the rivers. Frazil ice would grow on a line quite rapidly achieving a diameter of 32 mm in 15 min, on a 3.2 mm dia, line in the flume. In the river, overnight accumulations reached 20 cm in depth. A few drag force measurements were made which yielded an average shear drag coefficient of 0.16.The results suggest methods of increasing our control over ice.
Calibration of a 58 m wave flume
Authors: Muggeridge D. B. , Murray J. J.
Published: January 2010

A 58.27 × 4.57 × 3.04 m wave flume has been constructed and calibrated. The maximum wave height that can be generated in regular waves is 0.7 m at a water depth of 1.8 m. Random wave spectra have also been modelled in the flume for prototype wind speeds up to 25 m/s. The maximum significant wave height that can be generated at a 1 m water depth is 20 cm.A series of tests performed to verify design curves presented by Gilbert, Thompson, and Brewer show good agreement with the predicted values. The Pierson-Moskowitz spectrum was modelled between wind speeds of 5 and 25 m/s at suitable scale factors ranging from 1:50 to 1:150. All analysis was carried out in real time by means of an on-line computer.
Parametric study of standard RHS double chord K-joints
Authors: Korol R. M. , Keen R. G.
Published: January 2010

An ultimate strength theory is developed for double chord rectangular hollow section (RHS) K-joints that accounts for both perfectly plastic and strain hardening material characteristics. The parameters that are investigated are chord depth–width ratio, eccentricity, chord preloading, and diagonal–chord angle. Interaction curves are presented that relate the diagonal and chord axial forces for different combinations of the parameters. It is shown that joints may suffer significant reductions in strength with an increase in eccentricity for the case when shear capacity of the chord's webs does not govern overall strength.Various detailing alternatives are investigated to improve joint capacity for prescribed weldment lengths. These include altering the diagonal–chord angle and the chord depth–width ratio.
Freight facilities for central business district office buildings
Authors: Ho Herbert H. , Morrall John F.
Published: January 2010

Inadequate end-point facilities in office buildings for shipping and receiving freight are partly due to a lack of understanding of the urban goods movement problem by architects and engineers and partly due to inadequate municipal freight facility by-laws. The problems created by inadequate freight facilities impose a wide range of environmental, social, and economic impacts on an urban area. Because of the magnitude and extent of these impacts engineers involved with the planning, design, and approval of office buildings must take an increasingly comprehensive view of the range of factors that should be considered in the design and operation of office building freight facilities.This paper is based on a recently completed study of urban freight facilities conducted by the Department of Civil Engineering of The University of Calgary for the City of Calgary Transportation Department. The study included measurement of arrival rates and service times of delivery trucks, couriers, and service vehicles at office buildings in Calgary. These measurements, in addition to a survey of existing freight facilities in central business district office buildings, formed the basis for the development of a proposal to revise existing zoning by-laws regarding freight facilities. The primary deficiency of existing Calgary by-laws is that they overstate the need for delivery vehicle facilities by a factor of two for larger office buildings and neglect the space requirements for couriers and service vehicles. The paper includes a comparison of freight facility by-laws for office buildings in a number of selected Canadian cities.
The Lions' Gate Bridge — renovation
Authors: Buckland Peter G.
Published: January 2010

The entire roadway of the approach viaduct was replaced with minimal disruption to traffic. The design, tolerant of errors and maximizing prefabrication, achieved quick replacement. Foundations were rotated by inserting hinges and cutting through the mass concrete piers. Plans were prepared for replacing the suspended structure of the main spans without disrupting Monday to Friday traffic. Design criteria are given for limit states of old steel, buckling of rivetted compression members, fatigue resistance of welded tubular construction, and temporary obstructions in the roadway. The effects of turbulence on aerodynamic stability led to the use of solid guard rails. Problems associated with progressive replacement of the suspended structure are discussed. The importance of public information during reconstruction is emphasized.
Strength and durability of hot-press glued-laminated timber beams
Authors: Keenan F. J. , Kryla J. M. , Sandoe M. D.
Published: January 2010

Hot-press glued-laminated timber was manufactured exclusively by one Canadian laminator between 1967 and 1970. Members made by this process have been found to be capable of seriously delaminating in service. The purpose of this study was to determine the strength and durability of lightly-delaminated hot-press beams. Eight such beams, plus two conventionally manufactured Glulam beams, provided material which was tested in either flexural-shear, flexural-tension-perpendicular-to-glueline after accelerated ageing, or vacuum-pressure cycling. For the accelerated ageing tests, material was subjected to either zero, one, two, four, six, or eight cycles of alternating high (85%) and low (35%) relative humidity at 50 °C, corresponding to equilibrium moisture contents of 16 and 6%, respectively. Flexural-shear strength of the hot-press material was somewhat lower than that expected of conventional material. Vacuum-pressure cycling of hot-press specimens resulted in delamination values exceeding the permissible amount. The average flexural-tensile strength of conventional material was substantially higher and less variable than that of hot-press material, both before and after accelerated ageing. Moreover, the flexural-tension-perpendicular-to-glueline tests after accelerated ageing cycles resulted in increased amounts of gluebond failure in the hot-press material. The results of the accelerated ageing and vacuum-pressure cycling tests indicate that even lightly-delaminated hot-press material has an inherent ability to delaminate and may perform poorly in situations of cyclic moisture environments.
Fuel conservation in urban transportation by the optimum allocation of employment growth
Authors: Kumar M. S. Vijaya , Sargious M. A.
Published: January 2010

The amount of energy consumed in urban transportation is directly related to the number of vehicle-kilometres of travel. To reduce vehicle travel, strategies are needed to tackle its two components: the number of vehicle trips and their length. This study deals only with the second component.At present, various energy conservation strategies are being studied. The most important of these are: (1) improving the technical efficiency of the automobile by producing cars that are more fuel efficient and encouraging car pools — this can be effective in the short and medium term; (2) improving the urban transit system to increase the public transit modal share — this can also be effective in the short and medium term; (3) planning the urban structure in such a way as to reduce the number of vehicle-kilometres of travel — this can be effective in the longer term.In this study, an attempt is made to channel the growth in employment among the zones of an urban region in such a way as to provide maximum access opportunity with minimum travel requirements. The gravity model is used to simulate the pattern of trips to work and a performance measure is developed to evaluate the overall performance of the urban system. Calgary, Alberta, has been taken as a case study area in this analysis and a computer-aided investigation has been carried out to handle the allocation technique using a method of incremental maximization.The results of the study, when compared with the growth strategy proposed by the City of Calgary Planning Department, indicate that some savings in fuel consumption can be achieved by planning the location of future employment growth.
Thermocline drawdown above cooling water intakes
Authors: Elsayed Emad E. M.
Published: January 2010

An analytical expression was developed to define the incipient drawdown of a thermocline into a submerged intake equipped with a circular cover. The critical discharge at the incipient drawdown was expressed in terms of dimensionless variables defining the thermal structure of the surrounding water body and the geometric properties of the intake structure.The relationship was verified by laboratory experiments and by field data.
Velocity distributions under floating covers
Authors: Lau Y. L.
Published: January 2010

The [Formula: see text] turbulence model has been used to calculate the velocity distributions for a large number of channel flows with different top and bottom boundary roughnesses. The resulting distributions are used to review the standard procedures for stream gauging of ice-covered flows. It is found that the average of the velocities at [Formula: see text] and [Formula: see text] of the depth is indeed very nearly equal to the overall mean velocity. Examination of the velocity profiles shows that the profiles deviate from the logarithmic distribution for about 40% of the flow depth. Other flow properties, such as the location of the maximum velocity and the mean velocities in the top and bottom layers, are also examined.
Composite design method for masonry walls on steel beams
Authors: Smith B. Stafford , Pradolin L. , Rlddington J. R.
Published: January 2010

The paper describes a design method for structures consisting of a heavily loaded masonry wall supported by a steel beam, taking account of the composite tied-arch behaviour of the wall and beam. The design approach is based on the assumption of triangular distributions of vertical stress at the wall–beam interface, the length of the distributions being a function of the beam-to-wall relative stiffness. In the design method the beam flexural stiffness is calculated to give an adequate distribution of the interface stress so that the maximum stress in the wall does not exceed allowable limits. The beam is also designed with flexural and shear strengths sufficient to resist the bending moment, tie force, and shear forees applied by the normal and shear interface loadings. Experimental evidence is cited to support the assumptions and the resulting design method.
Concrete flat plates with well-anchored shear reinforcement elements
Authors: Voet A. Frank Van Der , Dilger Walter H. , Ghali Amin
Published: January 2010

Punching shear in reinforced concrete flat plates can cause brittle failure at a load well below its flexural strength. The present paper reports the results of a recent test series at The University of Calgary on full-size slab–column connections subjected to concentrically applied punching loads. Shear reinforcement elements in the form of vertical steel bars with square anchor plates at their ends were used. The number, cross sectional area, and distribution of the shear reinforcing elements around the column were the test variables.It is concluded that the shear strength in the concrete at a critical section outside the shear-reinforced zone decreases with the increase of the distance of the section from the column face. Provision of well-anchored shear reinforcement can increase the ultimate shear strength by 100%; equations to predict the ultimate strength are presented.
Internally loaded cylindrical shells
Authors: Sherbourne A. N. , Urrutia-Galicia J. L.
Published: January 2010

Simply supported cylindrical shells under internal fluid and granular loading are investigated.A Fourier series solution is presented and results are shown for various shell geometries. Experimental data are shown to agree with the theoretical solutions. The accuracy of the results is discussed and charts are given for direct use in the design of these structures.
The use of wide-flange shapes in transmission towers
Authors: Madugula Murty K. S. , Davalath Gupta S. R. , Rea V. L.
Published: January 2010

The members of self-supporting latticed electrical transmission towers customarily consist of rolled angle sections. Nowadays, with transmission voltages in the extra-high-voltage and ultra-high-voltage ranges, the leg members are required to carry very heavy loads, especially in the case of heavy angle and anchor towers. Results of a study carried out on wide-flange shapes, to investigate their suitability as alternative sections to welded and built-up angles, are presented. The world's first transmission tower that has wide-flange shapes for legs and arms, Ontario Hydro's 500-kV double circuit heavy angle dead end tower type V6H, is described.
Building deflections, distortions, and vibrations — a survey
Authors: Huggins M. W. , Barber J. D.
Published: January 2010

The introduction of limit states design procedures in building codes has led to an increased interest in the probability of distress in buildings. This note presents a summary of responses to a questionnaire mailed to Canadian consulting engineers and building officials in which they reported cases of deflection, distortion, and vibration distress in three classifications — minor, important, and major.
Plate reinforced square hollow section T-joints of unequal width
Authors: Korol R. M. , Mitri H. , Mirza F. A.
Published: January 2010

The carrying capacity of square hollow structural section T-joints stiffened by a rectangular flange plate is investigated for both branch bending moment and punching shear. The ultimate moment or load is determined from the simple yield line method of which one of three failure modes is applicable depending on the plate length. A large number of combinations of branch, chord, and plate sizes are analysed to provide a statistical basis for making recommendations of optimum plate lengths and thicknesses for stiffened joints in Vierendeel truss applications.
Floor vibration measurements in a shopping centre
Authors: Pernica G. , Allen D. E.
Published: January 2010

Vibration measurements have been correlated on five long-span floors in a two-storey shopping centre. The floors are used primarily as walking areas and have been considered satisfactory with respect to floor vibrations. Three of the floors are steel beam composite concrete deck construction, and two are precast, prestressed, concrete beam construction.Dynamic characteristics of the floors as determined by the heel impact test were compared with quiet occupancy criteria. Results suggest that quiet occupancy criteria can be increased by at least a factor of three for walking areas in shopping centres.Calculations of fundamental frequency and initial peak acceleration from heel impact for the five floors are also presented and the results compared with measured values.
Modélisation de fermeture des cours d'eau
Authors: Rohan Karol
Published: January 2010

For the construction of a rockfill dam in flowing water, caused by river closure or a dam collapse, generally a progressive lateral dumping of stones is considered. The aim of the study of this phenomenon in the hydraulic laboratory at the University of Sherbrooke was to determine an economic procedure for an actual power plant structure and, if possible, to draw some conclusions of general validity.Scale model techniques of river studies are well understood from the application of the laws of similarity of hydraulic flow and of bed load transport. It seems to be more difficult to extrapolate the results from scale model studies of a river closure, because of the uncertainty of extrapolation of some physical factors like turbulence intensity, form coefficient of solid material, friction and inertia forces of dumped particles, and their stability in connection with bottom roughness. The same uncertainty exists also in the extrapolation of the duration of closure for a specific frequency of dumping.
Analysis of freeze-up ice jams on the Peace River near Taylor, British Columbia
Authors: Keenhan T. , Panu U. S. , Kartha V. C.
Published: January 2010

Since the construction of the Bennett Dam on the Peace River in British Columbia, the temperature of flow releases from G.M. Shrum Generation Station, located at the dam, has been 0.5 °C or higher during the winter months. As a result, the progression of ice cover below the dam is inhibited and a long reach of ice-free river persists throughout the winter. During February, 1979 below normal air temperatures persisted in the area and the cover progressed to a point 103 km downstream of the dam, or 19 km upstream of the Water Survey of Canada (WSC) stream gauge at Taylor. This was only the second occurrence of ice cover at the town of Taylor since 1972, when an increase in generating capacity at the G.M. Shrum Station raised maximum powerhouse releases to 1580 m3/s.A series of ice jams at the leading edge of the ice cover formed as the cover advanced, producing water levels within Taylor that approached the maximum historic summer flood levels. The ice movement, including ice cover advance and retreat, ice levels, and jam formation were monitored and documented. The data provided an opportunity to examine various river ice simulation models and assess their applicability to the Peace River.
Cas historique de sédimentation du barrage Péligre, Haïti
Authors: Frenette M. , Tournier J. P. , Nzakimuena T. J.
Published: January 2010

The Péligre Dam in Haïti, on the Artibonite River, was built in 1956 for an expected life of about 180 years. Based on sedimentation data collected in 1925 and 1926, the average rate of silting in the reservoir was estimated at 3.45 × 106 m3/year. In 1979, however, an average sedimentation rate of 9.6 × 106 m3/year was established.Systematic observations were undertaken in 1961, 1977, and 1979 to explain the phenomenon and to predict the future rate of silting in the reservoir. The studies led to simulation, by means of a mathematical model, of the processes involved and have permitted reconstruction of the hydro-sedimentological events since 1956 as well as prediction of the future rate of sedimentation.In order to develop a methodology that has widespread applicability for predicting the rate of sedimentation, the main physical processes responsible for the patterns of deposition were used as common denominators: degradation of watershed and rivers, effects of deforestation, urbanisation, and agriculture, effects of flocculation and consolidation, effect of the reservoir geometry, expected sediment inflow, water inflow versus outflow, etc.On the whole, the model indicates very well the acceleration of the silting rate with an average increase of about 18% per year. The study thus shows that the sediment inflow took the form of a quadratic or exponential growth curve instead of a straight line. After 23 years the average silting is three times that of the design. The results show in conclusion how we must be careful in predicting long-term sedimentation rates in a reservoir since the lifetime of the dam is notably reduced. Keywords: erosion, sedimentation, reservoir, lifetime, simulation, degradation, watershed, design.
The grillage analogy in bridge analysis
Authors: Jaeger Leslie G. , Bakht Baidar
Published: January 2010

The grillage analogy method for analyzing bridge superstructures has been in use for quite some time. The idealization of a bridge by a grillage is not axiomatic and is not without pitfalls. An attempt is made in this paper to provide guidance on grillage idealization of various types of structure, together with the relevant background information. Specifically, the paper deals with the idealization of slab, beam-and-slab, cellular, and voided-slab bridges. Idealization of slabs of linearly varying thickness is also discussed. Guidance is provided on the mesh layout. Keywords: analysis, beam-and-slab bridges, cellular structures, flexural rigidity, grillage, idealization, load, mesh, slab bridges, torsional rigidity, voided slab.
Resistance coefficients from velocity profiles in ice-covered shallow streams
Authors: Calkins Darryl J. , Deck David S. , Martinson Carl R.
Published: January 2010

Techniques for analyzing flow velocity profiles for streams where the flow depth is less than 1 m should be employed with caution. The two procedures for calculating flow resistance based on the logarithmic law, (1) mean and maximum velocity determinations and (2) intereept evaluation of log depth – velocity plots, should yield the same results for the various resistance coefficients and shear stress values, but they do not. The former procedure generally predicts higher values than the latter and is recommended for shallow streams where the field data were collected. For a 3.8 cm diameter flow sensor, the minimum distance from a boundary to the position of maximum velocity for a good velocity profile appears to be roughly 15–20 cm.The fluid shear stress values for ice covers on this shallow stream range from 0.1 to 17 Pa, depending upon ice type and duration of the cover. The shear stress under frazil ice slush showed a drop of about one tenth the initial value over a 2-week period at one location. The measured division of flow velocities about the maximum velocity associated with the bed and ice boundaries indicated that the mean velocities were not equal but often differed by as much as 25–30%, generally being higher in the section associated with ice, i.e., a rougher ice boundary.The most consistent method of determining the resistance coefficients was to define the cross-sectional shape of the river and ice cover accurately, subdivide the flow areas, use the mean velocity data calculated from the velocity profiles, and then compute the resistance values accordingly. The sensitivity of the roughness coefficient is discussed in terms of its impact on determining the total stage of an ice-covered river.
Energy from waste in Niagara
Authors: Eidt Conrad H.
Published: January 2010

It has been determined that an energy-from-waste plant in The Regional Municipality of Niagara is feasible. The facility would burn all of Niagara's combustible waste, plus some from the neighboring regions of Halton and Hamilton-Wentworth, to produce steam for use at Ontario Paper's Thorold plant. Earlier, studies had been carried out to determine the quantity and quality of waste available.The Regional Municipality of Niagara, The Ontario Paper Company Limited, and the Ontario Ministry of Energy agreed to undertake a feasibility study that would determine the economic and technical feasibility of such a facility. This study was carried out by the consulting engineering firm, SNC/GECO Canada Incorporated, under the direction of a steering committee comprised of staff members from the Ontario Paper Company, the Regional Municipality of Niagara, the Ontario Ministry of Energy, and the Ontario Ministry of the Environment.The study was carried out in three phases; the first phase confirmed the waste quality and quantities and identified the characteristies of the steam used at Ontario Paper's Thorold plant. The second phase evaluated two turn-key proposals and recommended that the third phase, which was the economic analysis of the project, be carried out based on the turn-key proposal submitted by the joint venture of Waste Management of Canada Incorporated, Volund USA Limited, and Canadian General Electric Company Limited. It had earlier been decided to proceed using the proven technology of mass-burning.The proposal evaluated contained two alternatives, a 600-t/day plant and a 1200-t/day plant. It is concluded that the facility would provide the Ontario Paper Company with a long-term energy supply at an economic rate and eliminate the need for additional land for landfilling in the future, with its associated problems of leachates, gas generation, and many others.
Surges from ice jam releases: a case study
Authors: Beltaos S. , Krishnappan B. G.
Published: January 2010

Accounts by witnesses of spring ice breakup in rivers often mention violent ice runs with extreme water speeds and rapidly rising water levels. Such events are believed to follow the release of major ice jams. To gain preliminary understanding of this problem, an attempt is made to reconstruct a partially documented ice jam release reported recently by others. The equations of the ice–water flow that occurs after the release of an ice jam are formulated. It is shown that the problem may be approximately treated as a one-dimensional, unsteady, water-only flow of total depth identical to that of the ice–water flow, and average velocity. The retarding effect of the frequently encountered intact ice cover below the jam is considered implicitly, that is, by adjusting the friction factor so as to make the predicted and observed downstream stages equal. The effects of jam length are considered next by assuming longer jams of the same maximum water depth. The duration of the surging velocities increases with jam length and so does the peak stage. Less than 2 h after the jam release the surge was arrested and a new jam formed, causing further stage increases. Present capabilities of modelling the reformation process are discussed and the major unknowns identified.
Some hydrotechnical problems related to the construction of a causeway in the estuary of the Petitcodiac River, New Brunswick
Authors: Bray D. I. , DeMerchant D. P. , Sullivan D. L.
Published: January 2010

In 1968 about 21 km of the upper end of the Petitcodiac River estuary was cut off as a result of the construction of a causeway, the associated control structures, and a fish passage facility. The primary purposes of these engineering works are to provide a highway link across the estuary and to protect upstream agricultural lands from flooding during periods of high tides.Some of the practical problems that have occurred in the Petitcodiac River estuary as a result of the construction of the causeway are presented in this paper. These problems include: major geomorphological changes, annual changes in bed level near the causeway, beach formation upstream of the causeway, and net upstream transport of sediment through the fishway at the control structure.No detailed analytical solutions are presented due to the expense of extensive data collection and the difficulty of formulating adequate models for such physical systems. However, examples are given to show that limited field data and observations may be used to provide order-of-magnitudc estimates of anticipated changes and to develop an understanding of the dominant processes that are active in such an environment.
Modernizing irrigation systems in Alberta
Authors: Thiessen J. W. , Smith R. F.
Published: January 2010

Extensive agricultural development of the Canadian prairies did not take place until after construction of the first transcontinental railway in 1885. Since that time, more than 400 000 ha has been developed for irrigation in the semiarid southwestern part of the region.Early irrigation systems were based on contour canals and gravity irrigation. These systems are now being rehabilitated to improve efficiency and to minimize future maintenance requirements. The cost of upgrading existing irrigation systems is less than the cost of constructing new areas of expansion.Competing demands exist for a limited supply of water in southern Alberta. River basin planning studies have provided an inventory of potentially irrigable lands and water supply. These studies provide important guidelines in plotting a course for future water management and irrigation development. Keywords: irrigation, capital works rehabilitation, expansion, cost-sharing, conveyance efficiency, seepage, canal lining, crops, drainage, water application methods, farm efficiency, river basin planning, water balance model.
Adaptability in transportation systems: A case study of drivers' gap acceptance characteristics
Authors: Adebisi O.
Published: January 2010

An empirical illustration of the adaptability of transportation systems as it is reflected in drivers' gap acceptance behaviour is presented. Field surveys were undertaken at several uncontrolled urban intersections that were carefully selected in order to clearly show the response of drivers on minor roads, in their gap acceptance behaviour, to varying traffic flows on the main roads. The collected data were initially examined in an aggregated form. In addition, the data were subdivided according to flow categories observed on the main road and examined individually. Results from the latter show that critical gaps decrease monotonically with increasing flow on the main road. When the results from the aggregated and disaggregated analyses were compared, discrepancies exceeding 100% were obtained for the estimated critical gaps as well as for the computed probability densities of critical gaps over the population of drivers. It appears that results from the disaggregated analyses, which give greater insight into how drivers on minor roads adapt to varying traffic flows on the main roads, affirm the view that improved understanding of drivers' gap acceptance behaviour can be realized by taking adaptive features into account.
Construction planning of single-span bridges using precast, prestressed concrete beams
Authors: Fbreig Sami M.
Published: January 2010

In this paper representational data are given that can be used for the planning of single-span prestressed bridge construction. The project-network is represented, together with the critical path and time–cost relation, which has been calculated. Schedules for manpower and equipment required for project completion are also shown, as well as the owner's cash flow. The application of such data to construction of similar projects in different locations and/or in the future is discussed. The bridges under consideration were constructed using precast, prestressed concrete beams and the deck was cast in situ to act compositely with the beams. To establish these data, the daily work reports and progress payment certificates of five bridges, built in southern Ontario between 1976 and 1980, have been analyzed. Average values, based on the data of the five bridges, were utilized in this analysis.
Construction stages and design considerations for a curved box-girder bridge
Authors: Tadros Gamil , Ghali Amin , Dilger Walter
Published: January 2010

A concrete bridge, recently completed in Calgary, Alberta crosses the Bow River and passes over heavy traffic intersections at Memorial Drive and Edmonton Trail. The method of construction used required little scaffolding to support the forms and allowed smooth flow of traffic during the construction stages.In this paper the method of construction is described, some design considerations are discussed, and cost comparisons are made with designs for alternative methods of construction.
Prédiction des débits de ruissellement pour le contrôle des réseaux d'égouts unitaires
Authors: Patry Gilles , Marchi Gilles , Rousselle Jean
Published: January 2010

As point sources of pollution are being eliminated others, less apparent, are becoming increasingly threatening to many water users. Non-point sources of pollution generated by combined sewer overflows have been found to be responsible for many of our water quality problems. The purpose of this paper is twofold: (a) to offer a summary of the combined sewer overflow control problem, and (b) to suggest a methodology for the anticipation or prediction of runoff flows from an urban catchment.Two types of regression models designed to predict urban runoff are presented and compared with the calibrated runoff model ILLUDAS. The simplicity of regression models and their ease of application to the real-time automatic control of combined sewer overflows make their use very promising.
Substrate removal and sludge production in a batch activated-sludge process with blending
Authors: Droste Ronald L. , Bewtra Jatinder K.
Published: January 2010

Bench-scale studies were conducted on a batch-operated, activated-sludge system in which the mixed liquor was blended periodically in an Osterizer blender. A similar unit without mechanical blending was operated as a control. Synthetic organic feed of known characteristics was used as a substrate. Tests were conducted for mixed liquor volatile suspended solids (MLVSS), effluent chemical oxygen demand (COD), settleability, and oxygen uptake rate under steady-state conditions.Substrate uptake in both units was observed to be a rapid adsorption–absorption phenomenon. The nonremovable COD was significantly lower in the blended unit. Also, the oxygen uptake rates showed significant increases due to floc breakup. Settleability was good in the blended unit and the overall effluent quality had improved considerably.
Contribution à la simulation numérique des écoulements non permanents en milieu poreux
Authors: Marche C. , Chappet D.
Published: January 2010

The present article is a contribution to the study of unsteady, nonlinear, Darcy flow through porous media by use of a finite element approximation. Many mathematical models proposed assume that the acceleration is small and has nearly the same orientation as the velocity. Those hypotheses seem to be debatable in breakwater studies. A new treatment of the relevant equations is presented and the determination of the free surface is made by the residual flow scheme.
Alternative wastewater management strategies for rural and urban-fringe communities
Authors: Campbell P. C.
Published: January 2010

Due to rapidly rising costs for conventional sewage collection and treatment systems, there has been a reemergence of alternative approaches to wastewater management in small communities.Alternative systems are generally those that employ either septic treatment and ground disposal or soil absorption. The careful exploitation of the capability of the natural systems to assimilate community wastewater is the underlying principle behind the alternative approach, which can offer significant cost savings over conventional systems.The widespread occurrence of malfunctions of existing wastewater disposal systems in rural and urban-fringe areas leads to a requirement for improved maintenance of the systems. The septic system has been relegated to the role of country cousin in the field of wastewater management; this is due to a historic confusion between central and noncentral systems and the type of management that is applied to them.The Government of Nova Scotia, recognizing the need to develop and test alternatives, commissioned a study in 1978 to investigate the feasibility of municipal wastewater management for rural and urban-fringe areas of Nova Scotia. The study has demonstrated that such an approach is practical, with some limitations.Should land use planning continue to rely on building site approval criteria that are based solely on physical constraints for on-site sewage disposal? As the issues of protection of resource lands and the use of marginal lands for building become more critical, the physical and management systems applied to alternative wastewater management strategies will continue to gain importance in the fields of engineering and planning.
Analysis of box-girder bridges by grillage and orthotropic plate methods
Authors: Cheung M. S. , Bakht Baidar , Jaeger Leslie G.
Published: January 2010

The paper deals with the calculation of longitudinal moments and transverse shear in multi-spine box-girder bridges. Results from three-dimensional analyses by the well tested finite strip method are used to establish the limits of validity of the grillage analogy method and the orthotropic plate method. These methods are shown to give accurate results provided that, for the orthotropic plate method, the number of spines is not less than three.Since transverse shear is mainly responsible for transferring loads from one spine to another, the flexural ridigity of the deck slab, and hence the slab thickness, has little influence on the distribution characteristics of a bridge; this is demonstrated with specific examples. Thus it is shown that a multi-spine bridge with at least three spines can be idealized as an articulated plate, i.e., a specific orthotropic plate in which the transverse flexural rigidity is assumed to be negligible.The behaviour of multi-spine box-girder bridges can be characterized by a single dimensionless parameter, with the help of which a simplified method can be developed to calculate longitudinal moments and transverse shear.
Innovative approaches to sewage collection, treatment, and disposal: practices in northern Canada
Authors: Smith Daniel W. , Christensen Vern
Published: January 2010

Some components of the wastewater management systems used in northern Canada have undergone significant changes within the last ten years. The natural and imposed constraints are reviewed with special emphasis on the wastewater characteristics. Wastewater collection through the use of butt-welded polyethylene pipe, individual line service connections, and truck collection are discussed. Improvements in the disposal of undiluted and moderately, conventionally, and greatly diluted wastewater are outlined. The problems and improvements underway with greywater treatment and disposal are important for the improvement of living conditions. Also, current efforts to increase water conservation are noted. Keywords: cold regions engineering, wastewater treatment, sewage collection, sewage disposal, water conservation.
Bend losses in drop inlet spillways
Authors: Smith C. D.
Published: January 2010

The drop inlet spillway consists of a vertical riser open at the top and connected to a horizontal conduit or tunnel at the bottom. A 90° change in direction is required at the connection between the riser and the conduit. In the interests of simplicity a square bend, sometimes called a miter bend, is often used for small unimportant structures. This type of bend produces separation zones and large eddy losses (bend loss). At the other extreme is the fully curved bend, commonly used for large shaft spillways. A properly designed curved bend will eliminate separation and minimize head loss. However, layout and forming for construction of a curved bend for a tunnel is complicated and expensive because the elbow surface is of double curvature.In this paper the results of hydraulic tests on five bend designs are presented. It was found that a simplified design with only an inside curve performed almost as well as the fully curved bend. It is suggested that the proposed design will meet the requirement for many low head drop inlets where use of the fully curved bend is not warranted but the square bend is not satisfactory.
Case studies measuring the benefits of the HSS hump sequencing model
Authors: Shi Qizhou , Yagar Sam
Published: January 2010

A model, entitled HSS, for selecting the sequence in which trains are to be humped in a rail hump yard, was applied to the Canadian National Railways' Taschereau Yard in Montreal. Based on the promising results of an eight-train pilot study, two separate case studies were performed. The first study compared FIFO and HSS in sequencing the 57 trains that arrived during a 24-h period. The other compared current operations and HSS in sequencing the 169 trains that arrived during a three-day period. Both showed improvements using HSS, with estimated time savings of about 3 and 0.6 h per car at Taschereau Yard, and corresponding estimated inventory savings of about $4000 and $700 per day, respectively. Keywords: humping, HSS, sequencing, railcars.
Seismic tests on a model shear wall with friction joints
Authors: Baktash P. , Marsh C. , Pall A.
Published: January 2010

The behaviour of energy-absorbing friction joints in vertical connections was studied using a model on a shaking table. By varying the slip force in the joints it was shown that there is an optimum value that maximizes the energy dissipation and minimizes the stress for a given seismic intensity.Results given by nonlinear time history dynamic analysis are compared with values from the tests. A proposed approximate method for the calculation of the optimum slip force is given that agrees well with the other values obtained. Keywords: seismic response, tall buildings, friction joints, energy dissipation, earthquake resistant structures, model tests, dynamic analysis.
Calcul de la résistance pondérée en flexion des poutres à section mixte
Authors: Picard A. , Beaulieu D.
Published: January 2010

In this paper, two methods of analysis used to determine the factored moment resistance of composite beams are compared. The first method is the one recommended by Standard CAN3-S16.1-M78 (1980 revision). The second method gives the ultimate moment resistance which is multiplied by a "global" performance factor to obtain the factored moment resistance. An elaborate statistical analysis where the variability of the strength parameters has been taken into account was carried out to determine this "global" performance factor. The proposed value is based on the results of 12 420 computer analyses.The authors believe that the second method of analysis is more coherent. Moreover, that method is similar to the method used to determine the flexural strength of reinforced concrete beams. Since one of the objectives of code writing committees is to produce consistent standards, the second method seems more appropriate. (An English version of this paper is available upon request.)
Developments in the design of welded HSS truss joints with RHS chords
Authors: Packer Jeffrey A.
Published: January 2010

Recent developments in design proposals for rectangular hollow section truss joints are reviewed for statically loaded, single chord, planar truss connections having one compression bracing member and one tension bracing member welded to the chord face, with either a small gap or an overlap at the connection. After comparison with the results of many joint tests, undertaken both in isolation and in complete trusses in other countries, a relatively simple procedure for the design of such joints is advocated. The design method is presented in a format compatible with the Canadian Standards Association Limit States Design Code for Steel Structures.
Stochastic analysis of high flows in some Central British Columbia rivers
Authors: Waylen Peter R. , Woo Ming-ko
Published: January 2010

High flows derived from the partial duration series were analysed in terms of the probability distributions of magnitude, frequency, duration, and the time of occurrence. Simple methods of representing the timing and duration of high flows as stochastic variables are presented. Existing stochastic models are applied to the probability distributions of the annual frequency of high flows and their magnitudes. A consideration of the statistical properties of the above stochastic variables leads to the development of a technique with which floods exceeding any higher level of interest may be investigated without resorting to a reanalysis of the historical data. The proposed methodology was applied to the daily streamflow records of three rivers located in diverse hydrological environments in Central British Columbia. Good agreement between the computed and the observed data in all eases reflects the applicability of the technique.
Increased sump capacity – A model study
Authors: Kouwen Nicholas , Mohsen Mohammad F. N.
Published: January 2010

Increasing pump sump capacity by mere addition of more pumps is limited by the generation of vortices. In most cases the costs for changing sump dimensions to increase capacity are prohibitive. In a sump model for which three pumps would satisfy the Hydraulic Institute Standards, three arrangements were tested with five pumps to determine their acceptance for the increased load. These arrangements were the echelon, the inverted "Vee," and the upright "Vee" as shown in the paper. At this 67% higher pumping rate, the echelon and the inverted "Vee" arrangements were found acceptable. Besides increasing the capacity of existing sumps, adoption of these arrangements could yield substantial space savings in new pumping pits.
Fecal coliform loadings from birds on bridges
Authors: Palmer Merv D.
Published: January 2010

The fecal coliform loadings to the Rideau River from bird populations resident on bridges were measured for dry weather, summer, low river flows (8.5–17 m3 s−1). The Rideau River has typical velocities to 0.216 km h−1. The loadings were estimated by an intensive river sampling program over 4 weeks at river cross sections upstream and downstream of a bridge with birds on the bridge and without birds on the bridge. The birds were temporarily displaced from the bridge with bird nets. Statistical testing of the river cross section geometric means showed the birds do have a significant effect on river fecal coliform levels. From bird census, river water sampling data, and river flow data, a pigeon was estimated to generate on the average a daily loading of between 0.88 and 1.3 × 1010 fecal coliform organisms with a standard deviation of approximately 0.39 × 1010. An independent check on the validity of the estimated loadings from resident bird populations at another bridge produced results within 40% of the measured values. Keywords: fecal coliform loadings birds.
Powerhouse concrete quantity estimates
Authors: Gordon J. L.
Published: January 2010

In this paper formulae are developed for the rapid estimation of the hydroelectric powerhouse concrete volume for nine different types of surface powerhouses, containing high head vertical or horizontal shaft impulse units; high head Francis units intermediate head Francis, Kaplan, or fixed blade propellor units; low head horizontal shaft tube, rim generator, or bulb units; and low head vertical shaft Kaplan or fixed blade propellor units. Heads range from a minimum of 4.65 m up to a maximum of 825 m. Unit size ranges from a minimum of 3000 kVA to a maximum of 615 000 kVA. The formulae are based on statistics derived from 93 hydro developments. In addition formulae are developed for generator casing diameters as a prerequisite to the development of a chart which indicates whether the turbine or the generator will influence powerhouse concrete volume for intermediate head powerplants. Finally, the formulae are used to compare concrete volumes for horizontal and vertical shaft low head powerplants. Keywords: hydroelectric powerhouse, concrete volume.
Étude de formation de vortex au voisinage de l'aspiration verticale inversée dans un puits de pompage
Authors: Kougnima Tilena , Kahawita René
Published: January 2010

The purpose of the laboratory investigation reported here has been to study the conditions under which vortices appear in the free surface flow upstream of a vertically inverted intake in a circular sump. The influence of geometry, approach conditions, size, and relative position of the intake in the sump has been studied. The effect of viscosity, surface tension, and inertia forces on the formation of vortices has been examined. A discussion of the results and the principal conclusions drawn permit certain recommendations to be made at the conceptual stage of pumping pits.