bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultimate loads of orthotropic bridges continuous over isolated interior supports
Authors: Kennedy John B. , El-Sebakhy Ibrahim S.
Published: January 2010

The collapse loads of orthotropic bridges continuous over isolated interior column supports are predicted by means of the yield-line theory. Equations for the collapse loads are derived for bridges of skew and rectangular planforms, and for an arbitrary angle of inclination of the line joining the centres of the interior columns. The analytical results are verified by experimental test results from prestressed concrete bridge models. Uniformly distributed and concentrated loads as well as Ontario Highway Bridge Design truck loading can be accommodated. A design example illustrating the use of the derived equations is presented. Key words: bridges (orthotropic), isolated supports, model tests, skew, structural engineering, ultimate load.
Design factors for the scouring of deposited materials in water and wastewater treatment systems
Authors: Machina David W. , Bewtra Jatinder K.
Published: January 2010

Many water and wastewater systems require that sediments in the flow remain in suspension. Sometimes, auxiliary power sources, such as compressed air or pumping, are used to obtain scouring velocities in the system. The combined effects of pumping, compressed air, and gravity (floor slope) on the solid–liquid interaction and the velocity required to scour particles are presented herein.Two nondimensional parameters are developed to present data. Design curves for scouring sand, grit, and secondary sludge particles are presented and compared with data obtained for spherical particles. The particle terminal settling velocity is used to describe the significant particle characteristics. The use of prototypical particles and slopes, together with the dimensionless parameters, allows an application of results to prototype systems where auxiliary scouring sources may or may not be present.Using the information presented, it is possible to design water and wastewater systems in which particles must remain in suspension, with or without the use of auxiliary power sources. Key words: scouring velocity, settling velocity, compressed air, pumping, wet well floor slope, suspended particles.
Effective lengths of laterally continuous, laterally unsupported steel beams
Authors: Schmitke Calvin D. , Kennedy D. J. Laurie
Published: January 2010

Laterally unsupported steel beams of sufficient length may fail by elastic or inelastic lateral–torsional buckling. The fundamental equations governing elastic lateral–torsional buckling, taking into account such parameters as the shape of the bending moment diagram, the level of application of the load, and the effect of end restraints to lateral movement and to twist, are reviewed. Provisions in the current CSA Standard CAN3-S16.1-M84 are discussed. The methods currently available for dealing with the interactive lateral–torsional buckling of laterally continuous beams are evaluated statistically. Two new methods for considering this interaction, called the iterated effective length method and the equivalent beam method, are presented. A statistical evaluation of these methods shows that they are in reasonable agreement with available test data. Resistance factors for use in limit-states design are developed for the existing methods discussed as well as for the new methods. Key words: beam, bending moment, buckling, effective lengths, elastic, inelastic, lateral–torsional buckling, laterally continuous, steel.
Seismic loading provision changes in National Building Code of Canada 1985
Authors: Heidebrecht A. C. , Tso W. K.
Published: January 2010

This paper describes the process by which Canadian seismic loading provisions are developed and then details the primary changes being introduced in the 1985 edition of the National Building Code of Canada. The most significant change is the inclusion of new seismic zoning maps, based on a new seismic risk methodology, a new probability level, and additional seismic zones, and incorporating both horizontal ground velocity and acceleration as zoning parameters. The format of base shear calculation is revised to incorporate these changes, including the specification of a new seismic response parameter. The base shear formula is calibrated to ensure that, on a cumulative basis throughout the country, the level of seismic loading remains unchanged. Additional changes discussed in the paper include the removal of dynamic analysis as a specific option in the base shear calculation and some significant changes in the calculation of torsional effects.
Shear strength of spruce glued—laminated timber beams
Authors: Keenan F. J. , Kryla J. , Kyokong B.
Published: January 2010

The effect of size on longitudinal shear strength has been well established for Douglas-fir glued–laminated (glulam) timber beams. The present study examined whether this phenomenon exists in glulam beams made of spruce. The experiment consisted of three projects in which beams of various sizes were tested under concentrated mid-span load. The project A beams had clear spruce webs and white elm flanges with cross-sectional dimensions varying from 25 × 25 mm to 75 × 75 mm. The project B beams had spruce glulam webs with Douglas-fir flanges; cross sections ranged from 20 × 100 mm to 90 × 200 mm. In project C, three groups of 10 replications of commercially representative sizes of glulam beams were made from stiffness-rated spruce–pine–fir lumber. The beam cross sections were 76 × 200 mm, 76 × 400 mm, and 127 × 400 mm.The results indicated that depth, width, and shear plane had significant effects on the longitudinal shear strength of the beams in project A. Depth, width, and shear span of the small glulam beams in project B also had highly significant effects on shear strength. However, no effects of depth and width on the shear strength of glulam beams in project C were found. Regression analysis showed no dependence of shear strength on sheared volume for the beams of all three projects. The three-parameter Weibull model also failed to predict the near-minimum shear strength of spruce glulam beams. The results suggested that the lower-bound shear strength of spruce glulam beams is a constant (regardless of beam volume) and could be used as a single characteristic value for glulam design in shear. Further review of published data indicates that this may also be the case for Douglas-fir glulam but with a lower characteristic value than for spruce.
Analysis of continuous steel plates subjected to uniform transverse loads
Authors: Ratzlaff K. P. , Kennedy D. J. L.
Published: January 2010

The economic design of steel caissons for drilling and production platforms in the Arctic Ocean, formed from steel plates and supported by a rectangular grid of stiffeners, beams, and girders, requires that the full strength of the plates be mobilized to withstand extreme ice forces. A comprehensive method of analysis is needed to describe the behaviour of continuous steel plates into the inelastic range when they are acted upon by transverse loads. From this analysis, design procedures could then be developed.An extensive literature search has not revealed that satisfactory solutions exist for the load–deflection response of transversely loaded flat plates beyond the elastic limit when both flexural and membrane action are taken into account. Experimental data available in the inelastic range of behaviour are also limited.By considering various limiting simplified behavioural modes for the load–deflection response of uniformly loaded flat plates of zero aspect ratio, possible load–deflection domains are established. The limiting responses investigated are: elastic–inelastic flexural action, elastic membrane action, inelastic membrane action with increased stiffness resulting from increased Poisson's ratio in the inelastic range, elastic flexural membrane action, and action of a fully yielded cross section in flexure that gradually gives away to a fully yielded cross section in tension. Within the domain so established, a load–deflection behaviour is proposed that is in reasonable agreement with the results of the limited test data available. The results of a finite element analysis using the ADINA computer program are also in reasonable agreement with the proposed analysis. Design applications are discussed. Key words: deflection, elastic, elastoplastic, flexural resistance, membrane force, membrane resistance, plates, steel, strains, stresses, transverse load.
Standardized flexible end plate connections for steel beams
Authors: Kriviak Gary J. , Kennedy D. J. Laurie
Published: January 2010

A flexible end plate connection consists of a plate fastened to both sides of the web of a beam by fillet welds. Bolted field connections are used. The connection should transmit vertical shear and allow beam end rotations to occur without the development of significant moments. It is common practice to evaluate the shear capacity of these connections neglecting the presence of secondary forces, which can develop when the connection rotates.Existing analytical models of the moment–rotation behaviour correlate well with test results. These models consider both the flexural and membrane response of the connection in the upper tensile zone and use an empirical relationship to predict the force developed in the lower compression zone. In some tests undesirable impairment of connection flexiblity occurred when the bottom flange of the beam contacted the support.A limit states design model has been developed, which better predicts the moment–rotation characteristics of the connection and which also predicts the reduced vertical shear capacity of the connection due to secondary forces. Consideration of the secondary forces results in connections being designed with more consistent safety levels.An interactive computer program has been developed to design flexible end plate connections using this model. The program is attached to a data file containing the geometric properties of all standard steel flexural shapes available in North America. By specifying any of these shapes along with the desired material properties, loading conditions, connection geometry, and associated connection component costs, a designer can use the program to rapidly prepare customized connection designs or design tables. Key words: beams, connection, end plate, flexible, interactive computer program, joints, limit states design method, plastic deformation, shear strength, steel structures, structural analysis, structural design.
Three-dimensional solid finite element models for computing compressive stiffnesses of bonded rubber blocks
Authors: Lau Ming G.
Published: January 2010

This paper describes how the compressive stiffnesses of bonded rubber blocks can be obtained by modelling the blocks using three-dimensional solid finite elements, each of which has eight nodes. The application of a readily available finite element analysis computer program, called TEKSAP, to the three-dimensional models yields a computer output of static displacements of the rubber models, subjected to compressive loads within the linear range. The shape factor effect is taken into consideration in the analysis.Four rubber models of the same loaded area, but different force-free areas, are used in the study. Their compressive stiffnesses as obtained by the TEKSAP program are found to compare satisfactorily with those obtained both by experiment and by two known empirical methods. Five rubber models with metal inserts are also studied.In the computer analysis, the rubber model is assumed to possess elastic and isotropic material properties. It is also assumed that the model is nearly incompressible. A Poisson's ratio close to 0.5 is used in the analysis. The boundary integral equation method is mentioned as a suitable method for solving problems involving fully incompressible material.Some engineering applications of bonded rubber blocks as load bearings are discussed. Key words: finite element, compressive stiffness, rubber block.
Trapezoidal side-channel spillways
Authors: Hager Willi H.
Published: January 2010

Steady flows in trapezoidal, prismatic side-channel spillways are analysed using a hydraulic approach. Distinction between channels of small and moderate bottom slopes is made. All results are presented in typical nondimensional quantities, by which an immediate application is made possible. Key words: open channel flow, spillway, gradually varied flow, discharge supply, hydraulics.
Degradation of the South Saskatchewan River below Gardiner Dam
Authors: Galay V. J. , Pentland R. S. , Halliday R. A.
Published: January 2010

The construction of Gardiner Dam on the South Saskatchewan River has resulted in the trapping of substantial sediment loads within the reservoir, causing some degradation of the riverbed below the dam. Analysis of cross-section and sediment data collected since the closure of the dam indicates that the average bed level has dropped 2 m (6.5 ft) downstream of the dam and that the bed has started to armour (become coarser). The degradation has progressed approximately 8 km (5 mi) below the dam. The pattern of the river channel has not altered significantly and the river has become more stable since the operation of the dam, especially in the lower reach just above Saskatoon.Detailed computations using the U.S. Army Corps of Engineers HEC-6 sediment model indicate that, by the year 2001, total degradation may be about 5.3 m (13.8 ft). The computer model also verifies that a high flood release could result in a substantial increase to the degradation that has already taken place. Key words: river behaviour, degradation, fluvial processes, sediment routing model.
Hydromechanics of submarine pipelines: design problems
Authors: Herbich John B.
Published: January 2010

In recent years, the size, number, and applications of offshore pipelines have been steadily increasing. The design and construction of pipelines in offshore cold regions calls for special measures (such as deep burial) because of seabed scouring caused by ice.Various societies and associations have pointed out the deficiencies in the state-of-the-art areas of environmental, design, and construction factors, particularly those dealing with structural, external pressure effects, and depth of burial. It has also been recommended that more data be obtained in order to fully evaluate pipeline–soil interaction. Also, field measurements of velocities, accelerations, and forces causing scour around pipelines would greatly enhance our understanding of offshore pipeline behavior.Offshore pipelines fail in many different ways, and each mode of failure should be examined individually. Because of the complexity of the ocean environment it is quite difficult to evaluate pipeline failures in detail.Environmental factors such as hydrodynamic wave forces and currents, buoyancy forces due to liquefaction of sediment, and scouring potential are presented. The dynamics of scour, incipient sediment motion, depth of scour, and scour patterns around pipelines are also reviewed as well as the maximum scour depths as a function of bottom current velocity.Methods for scour protection in shallow and deep water are described as well as the need for inspection and maintenance to prevent failures. Key words: pipelines, offshore, hydrodynamic forces, cover, scour.
A marked Poisson process model of summer rainfall in southern Ontario
Authors: Bonser J. D. , Unny T. E. , Singhal K.
Published: January 2010

A mathematical description of summer rainfall occurrences in southern Ontario is developed in this paper. The theory of Poisson point processes with specific application to rainfall modelling is presented with a critical review of previous literature on Poisson rainfall models. A marked Poisson process model of summer storms is formulated, using the marks to represent the random duration and intensity of the events. Model parameters are estimated for four locations in southern Ontario using a total of 48 seasons of hourly rainfall data. The model is applied to calculate the seasonal return period of extreme storms and the probability distribution of total seasonal rainfall volume. These two examples demonstrate the accuracy and usefulness of the model. Key words: rainfall, storm duration, storm intensity, temporal storm pattern, probabilistic model, Poisson process, exponential distribution, gamma distribution, Weibull distribution.
Storm water pollution modelling: buildup of dust and dirt on surfaces subject to runoff
Authors: James William , Shivalingaiah Boregowda
Published: January 2010

Many runoff models are currently in use to predict both the quantity and quality of storm water runoff. In most models, the quality algorithms need further development to gain the confidence of model users. The writers have attempted to disaggregate the accumulation process and to develop improved algorithms for pollutant buildup. The factors and processes that affect buildup include atmospheric dustfall due to plumes of dust-laden air, wind effects, vehicles, intentional removals (e.g., street cleaning), special activities (such as construction and demolition), biological decomposition, and population-related activities (e.g., vegetation density, insecticides, herbicides, fertilizers, and lawn cutting). Mathematical expressions for each of these mechanisms are presented and utilized to develop algorithms in the RUNOFF module of the SWMM3 package.A separate multiregression model is used to generate atmospheric dustfall from meteorological information; this is input to the new program (NEWBLD) to calculate pollutant accumulation on individual subcatchments. NEWBLD is interfaced with the RUNOFF block of SWMM3. A sensitivity analysis is carried out using data for the Chedoke Creek catchment in Hamilton, Ontario. The modified version of the SWMM3 RUNOFF block developed herein by incorporating the new water quality algorithms is called CHGQUAL. It is applied to an urban catchment in Hamilton, Ontario. Key words: storm water models, dust and dirt buildup, storm water pollution, urban hydrology, air pollution.
Laboratory tests on surges created by ice jam releases
Authors: Wong J. , Beltaos S. , Krishnappan B. G.
Published: January 2010

Laboratory tests were conducted to investigate the unsteady-flow conditions after the release of an ice jam. The tests revealed that the presence of the moving ice has no discernible effect on the characteristics of the surge that follows the release of the jam and that the model of S. Beltaos and B. G. Krishnappan gives good predictions of the water levels and fair predictions of the water speeds.
La viabilité des bétons du Québec: le rôle des granulats
Authors: Bérard Jean , Roux Richard
Published: January 2010

The petrographic study of numerous concrete structures in Quebec has revealed the extent of postconstruction chemical reactions. Those reactions between the aggregates, which form 70% of the volume of the concrete, and the cement paste result in early deterioration and undesirable mechanical deformation of the structures. From this study, it appears that the coarse aggregates can react in three different ways: (a) by peripheral reaction, which is the case for massive granitic rocks, (b) by bulk swelling, as illustrated by the Potsdam orthoquartzite, and (c) by formation of silica gel veinules within the aggregate, as shown by some Trenton limestone. Considering these three mechanisms, it is easy to understand why certain aggregates react rapidly, that is within a few months, whereas others show signs of distress only after scores of years. Using the three rock types cited above, we have also tried to evaluate existing concrete standards and their capability to detect the most important pathologies encountered in concrete. Key words: concrete, aggregate, alkalis, disintegration, expansion, testing, durability.
Engineering education in Canada—the early years
Authors: Morris Glenn A.
Published: January 2010

The beginnings of engineering education in Canada, in the mid-19th century, are described. The development of engineering programs in 10 of Canada's universities is outlined. The activities of a number of pioneers in engineering education are described, and the curricula for several of the early civil engineering programs are presented. Key words: history, education, civil, engineering.
Computation of steady-state, gradually varied flows in parallel channels
Authors: Chaudhry M. Hanif , Schulte Andreas M.
Published: January 2010

To compute the water-surface profiles in steady-state, gradually varied flows in open channels, an algorithm is presented that allows calculation of the flow depths and discharges at all sections of a parallel-channels system simultaneously instead of by the presently used trial-and-error computations. This algorithm is accurate, efficient, and suitable for computer solution. As compared to other methods, it may be used directly for computing flows in parallel channels without necessitating graphical plots or other trial-and-error manual computations. A procedure is outlined so that the resulting matrix for a parallel-channels system may be banded in order to increase accuracy and to reduce computer time and storage. A parallel-channels system is solved for illustration purposes and the results are compared with those obtained by the fourth-order Runge–Kutta method. Key words: backwater profiles, computer algorithms, gradually varied flows, mathematical models, Newton–Raphson method, open-channel flows, parallel channels, water surface profiles.
Classification of Saskatchewan highways according to type of road use: testing of a model
Authors: Wyatt Jon J. , Sharma Satish C.
Published: January 2010

The purpose of this paper is to test a recently proposed model of road classification for use by provincial highway agencies. The proposed model to be tested is intended to classify roads according to temporal volume variations, road use characteristics, such as trip purpose, and trip length distribution. The proposed model, which was developed by using Alberta highways data, is applied to Saskatchewan highways to evaluate its classification results. For the purpose of this study, a total of 31 permanent automatic traffic recorder sites in Saskatchewan is investigated. The application of the model to Saskatchewan highways results in six main groups according to the trip purpose and trip length distribution characteristics. The paper defines and discusses these classes in detail and compares them with the existing classification of Saskatchewan highways. The model produces similar road classes for Alberta and Saskatchewan highways. The similarity of road classes for the two provinces has implications for a standard classification of provincial highways. Key words: highway classification, road use, traffic, transportation, traffic volume patterns.
Analyses and tests to determine the effective widths of composite beams in unbraced multistorey frames
Authors: Fahmy E. H. , Robinson Hugh
Published: January 2010

This paper concerns the analysis and testing of 10 cantilever composite beams incorporating ribbed metal deck, representing the positive moment beam–column connections in an unbraced steel frame with composite floor beams. The positive moment beam–column connections arise from lateral forces on the unbraced frame. The effective widths of the slabs for strength and stiffness calculations have been determined from analysis. Agreement between the calculated strain distributions across the concrete slab width and the corresponding measured strain distributions was attained. Use of the calculated effective widths of the slab for strength together with a concrete strength of [Formula: see text] gave good agreement with the measured positive ultimate moment capacities of the cantilever composite beams subjected to upward end test loads.
Behaviour and ultimate strength of continuous steel plates subjected to uniform transverse loads
Authors: Ratzlaff K. P. , Kennedy D. J. L.
Published: January 2010

The authors previously established that an initially flat rectangular steel plate, clamped on all four edges, displays three modes of behaviour as the intensity of a distributed transverse load increases: elastic flexural-membrane action, inelastic flexural-membrane action, and inelastic-membrane action.For a long narrow plate, elastic flexural-membrane action exists up to the load at which yielding of the extreme fibres along the long edges occurs. Subsequent plastic hinge formation along the long edges reduces the stiffness. The second stage ends with complete yielding in tension along the long edges. From this point onward, the plate acts essentially as a membrane straining inelastically as yielding gradually progresses from both edges toward the centre. A lower bound to this behaviour is obtained by assuming that Poisson's ratio is the elastic value and the maximum membrane stress is the yield stress. A higher lower bound is obtained using the plastic value of Poisson's ratio. The load–deflection curve gradually moves from the lower value to the higher and, because the edge forces can exceed yield, will finally exceed the latter, as confirmed by tests.A finite element program modelling plane stress conditions, the inelastic Poisson's ratio, and the stress–strain behaviour to failure gave a load–deflection response closely following the three predicted regions of behaviour. Two failure criteria have been established: a limiting tensile strain due to bending and tension at the edge and the shear resistance there. The behaviour and failure loads have been confirmed by two tests. Strain measurements taken during the tests substantiate, in general, the predicted behaviour.Implications of using the ultimate strength of plates for the design of offshore structures for oil exploration and production in the Arctic are presented. Key words: deflection, design, finite elements, inelastic, membrane, plates, steel, strains, stresses, transverse load, ultimate strength.
A critical analysis of residential flood damage estimation curves
Authors: McBean Edward , Fortin Michael , Gorrie Jack
Published: January 2010

A critical review of the problems encountered in attempting to quantify flood damage is used to demonstrate inconsistencies, omissions, and variabilities among previous studies and procedures. A reasonable procedure for updating residential depth – damage data from previous studies is shown to involve use of the all-items consumer price index. Recommended strategies for flood damage estimation involve calibration of synthetic stage – damage data to observed flood damage data.
Multiparametric sensitivity analysis of energy production projects
Authors: Beaudry Jean-Paul , Langlois André P.
Published: January 2010

Optimization studies of an energy production project or complex consist in determining the economic general dimensioning of the works during the prefeasibility or the feasibility stage of the studies. As these first studies are part of the iterative system planning process, they should include very exhaustive sensitivity analyses on the accuracy of all technical and economic parameters, although (and even because) so much data is uncertain during this phase.After a review of the mathematics of discounting and of the decision-making economic criteria, a nomographic approach is presented that allows the optimum dimensions of the project to be determined as a function of any combination of the following parameters: imposed discount rate, total investment cost, variations in cash flow pattern, delay in commissioning date, life expectancy of the works, monetary value of energy and power, system load growth, seasonal pattern of energy demand, effect of secondary energy, long-term average river flow, and effect of regulation on downstream developments.
LAVSED-II—A model for predicting suspended load in northern streams
Authors: Julien P. Y. , Frenette M.
Published: January 2010

The model LAVSED-II (LAVal SEDimentological model number II) has been developed to evaluate the suspended load in northern streams that results from rainfall and snowmelt erosion on upslope areas. The most important parameters are (1) the physical characteristics involved in soil erosion processes and (2) the climatic parameters on a month-to-month basis. Two fundamental relationships are obtained from the governing physical processes and empirical relationships describing snowmelt and sediment transport. The model has been applied to four large watersheds, tributaries of the St. Lawrence River. The computed sediment yield compares very well with the measured suspended load (mostly wash load) in the rivers. The magnitude of the peak during spring is particularly well predicted. The computed sediment yield is shown to be very sensitive to meteorological data. In the case of ungaged watersheds, the model can be applied to estimate the sediment yield.
Modélisation des solides dissous en rivière à l'aide des composantes de l'écoulement
Authors: Morin Guy , Couillard Denis , Cluis Daniel , Jones H. Gérald , Gauthier Jean-Maurice
Published: January 2010

The proposed model calculates the concentrations of dissolved solids in rivers at any point within a watershed, using the components of a conceptual hydrological model (CEQUEAU). For this purpose, the watershed is divided grid-wise into parcels for each of which a daily mass balance is computed. This mass balance takes into account the dissolved solids loads associated with the three inflows considered by the hydrological model, namely surface runoff, interflow, and base flow, as well as the loads associated with municipal and industrial point sources. The model has been applied to the Sainte-Anne River, Québec (total watershed area: 2700 km2) and the calculated values show satisfactory agreement with the observed concentrations at two sampling points (Chute Panet: 1550 km2 watershed area; La Pérade: 2700 km2 watershed area). Key words: modelling, river, dissolved solids, runoff, interflow, base flow.
Performance evaluation of alternate policies on reservoir system operation
Authors: Weeraratne J. R. , Logan Lloyd , Unny T. E.
Published: January 2010

This paper discusses within the context of the Grand River system operation the application of the three performance criteria introduced earlier by T. Hashimoto, D. P. Loucks, and J. R. Stedinger. These criteria evaluate the performance characteristic in respect to system failure, system recovery, and system vulnerability with regard to extreme (costly) failures for alternative operational policies. System robustness, also discussed by Hashimoto and co-workers, is used to measure the economic flexibility of system operation to adapt to uncertainties of future demand. The primary objective of the presentation made herein is to establish the role of these criteria in a decision-making process in the operation of the system.
Size effects in timber explained by a modified weakest link theory
Authors: Madsen Borg , Buchanan Andrew H.
Published: January 2010

This paper represents a new approach to size effects in timber. The design process in Canadian Standards Association code CAN3-086-M80 allows for size effects in shear and in tension but not in bending. A large number of bending test results arc analyzed in this paper to show that size effects in bending are very important. A modification is made to the traditional weakest link theory for size effects to reflect the anisotropic nature of timber. Good agreement is obtained between tests and theory. The theory enables us to compare tests with different spans and (or) load configurations with an understanding not previously possible. Results from several large testing programs are used to quantify the theory. For bending members, length effects and load configuration effects are found to be much more important than depth effects, and a simple design method is proposed. Information for tension members is less comprehensive; nevertheless, a tentative suggestion for the design of those members is included.
Unusual Canadian floods and the Creager diagram
Authors: Neill Charles R.
Published: January 2010

A number of unusual flood discharges in Canada are plotted on the Creager diagram of 1945, which was based on a compilation of unusual floods in the United States and other countries. Values of Creager's coefficient C for the Canadian floods lie mainly between 20 and 45. Readers are invited to contribute further data on known Canadian floods and on project estimates of PMF (probable maximum floods) and SPF (standard project floods) so that expanded versions of the table and diagram can be included in a forthcoming flood guide for Canada.
Effects of intermediate diaphragms in distributing live loads in beam-and-slab bridges
Authors: Cheung M. S. , Jategaonkar R. , Jaeger Leslie G.
Published: January 2010

For small-span to medium-span bridges, the beam-and-slab type of construction is popular, mainly because of its ease of construction, and is preferred in practice even though this form of construction may sometimes exhibit rather poor transverse load distribution qualities. This deficiency is often reduced by the incorporation of one or more diaphragms in the deck construction. Although the use of diaphragms in beam-and-slab bridges is very extensive, their use is almost entirely empirical rather than based upon any logical method of analysis. Thus, the requirements for diaphragms that are found in codes of practice all over the world usually consist of simple and arbitrary statements. It is proposed here to carry out a thorough theoretical study of the structural behaviour of diaphragms in beam-and-slab bridges, with a view to establishing this behaviour on a well-reasoned footing. Key words: beam-and-slab bridge, diaphragm, cross frame, grillage analogy, finite element method, orthotropic plate theory.
A 1-h urban design storm for Canada
Authors: Watt W. E. , Chow K. C. A. , Hogg W. D. , Lathem K. W.
Published: January 2010

The advent of stormwater modelling techniques has resulted in the need for a Canadian urban design storm. As a first stage in meeting this need, a 1-h urban design storm has been developed. This design storm, which is fully described by two parameters and the rainfall depth as given by Atmospheric Environment Service (AES) intensity–duration–frequency data, is specified for a wide range of return periods for all regions of Canada. Extensive comparisons with observed 1-h storms, both in the temporal domain and the frequency domain, indicate that the two-parameter mathematical model is capable of simulating individual rainfall events and an average or 'design' event for any particular site. The design storm model has been extended on a regional basis by evaluating the two parameters for each of 45 AES stations across Canada. Regional values of the parameters have been derived so that a design storm can be determined for an area without rainfall records. Key words: design storm, urban drainage, storm water, rainfall, temporal distribution, regional analysis.
Design and construction of a 3 km (2 mi) long shoreline protection system for the City of Luna Pier
Authors: Becker N. K. , Patterson H. R. , McCorquodale J. A.
Published: January 2010

In 1982, N.K. Becker & Associates Ltd. designed a precast concrete flood protection and beach restoration system for the 3 km (2 mi) long Lake Erie shoreline of the City of Luna Pier, Michigan. The construction of these works, which included beach sills, shorewalls, and a marina basin, was completed in 1984.The shorewall system is unique in that it was designed of interconnected, open-ended, earth-filled, thin-walled precast concrete cylinders, placed on-end and in-line to form a continuous wall. This seawall design was selected by the City of Luna Pier over alternative systems because it was estimated to cost 50% less than conventional steel sheet piling or cast-in-place concrete systems.During the final design, hydraulic model tests were carried out at both the University of Michigan and the University of Windsor to study the uprush, scour, longshore transport, and wave pressure characteristics of the proposed system. The methods used to design this economical and functional flood protection system are presented along with an analysis of its performance to date. Key words: beach, beach sill, flushing, hydraulic model testing, ice, longshore drift, overtopping, precast cellular concrete wall system, scour, shorewall, uprush, water levels, waves, wave deflector.
Modélisation d'un écoulement tourbillonnaire en régime permanent
Authors: Ouellet Y. , Dupuis P. , Soulaïmani A.
Published: January 2010

The presence of a cove, either natural or artificial, along a main watercourse is often considered to be an ideal location for a small harbor. However, when the current in the main channel is relatively large, an eddy is generated inside the small bay, thus hindering its use as a harbor for ships. The use of mathematical modelling of this phenomenon to find a solution to the problem is rather difficult. Based on a case study, i.e. a small artificial bay along the Saguenay River at Chicoutimi, Québec, a methodology is presented and a model developed to give a good representation of this phenomenon. Key words: flow, finite elements, harbor, modelling, vortex.
Stability analysis of soil–steel structures
Authors: Dessouki Abdelrahim K. , Monforton Gerard R.
Published: January 2010

A finite element analysis to predict the instability of soil–steel structures is presented. For the steel segment, beam–column elements that accommodate geometric nonlinearity as well as plastic hinge formation are used. Constant and linear strain triangular and quadrilateral elements simulate the soil media in conjunction with spring-type interface elements. A hyperbolic stress–strain relationship models the soil remote from the conduit; an elastoplastic soil model is chosen for regions of high stress gradients above and around the conduit. The formulation is capable of following the initiation and propagation of failure in the soil and its effect on the conduit stability. Analytical failure loads are compared with experimental results and those predicted by the Ontario Highway Bridge Design Code (OHBDC) and the American Association of State Highway and Transportation Officials (AASHTO) specifications.
Comparaison des performances relatives à un modèle déterministe et à un modèle stochastique de température de l'eau en rivière
Authors: Marceau P. , Cluis D. , Morin G.
Published: January 2010

A stochastic model of water temperature has been established and then applied to data taken from measurements on the Sainte-Anne River, Québec; its development uses the Box–Jenkins modelling approach. As well, an existing deterministic water temperature model had been applied to the same data and a comparative study between the two models is made. This comparison contains a graphical daily analysis, a statistical analysis including the calculation of root-mean-square error, and a comparative performance study. With these criteria, no overall domination of one model over the other has been noticed. Nevertheless, an analysis based on the purpose of the model and on the data available allows choice of the appropriate model. Key words: model, temperature, river, stochastic, deterministic, performance.
Accumulated basin storage as a factor in the correlation structure of annual peak flows on the Red River
Authors: Booy C. , Lye L. M.
Published: January 2010

The well-established occurrence of exceptionally high floods on the Red River prior to the record of annual peak flows at Winnipeg is an important factor in the flood risk assessment for that city and for the entire Red River valley. But the weight given to this occurrence is quite dependent on the autocorrelation structure assumed for the spring peak time series. It is therefore important to decide whether the clustering of high peak flows, which can be observed in the record, is a mere chance phenomenon or indeed a characteristic of the runoff process. In earlier studies this clustering was found to be significant in a statistical sense. The present study aims at finding a physical explanation for this particular type of correlation structure. It presents the accumulated basin storage (ABS) as a physically based parameter that measures average soil moisture conditions in the drainage basin. The reconstructed record of ABS values just prior to the spring runoff shows a very high first-order autocorrelation coefficient. Relatively wet and relatively dry soil conditions therefore tend to persist over long periods. Since the magnitude of the spring peak is significantly affected by soil moisture conditions prior to snowmelt, the structure of the annual ABS time series can be expected to be reflected in the peak flow time series. This was found to be the case. The study thus supports earlier conclusions based on statistical evidence that the conventional assumption of serially independent spring peak floods seriously underestimates the flood risk for the City of Winnipeg and the Red River valley. Key words: accumulated basin storage, Red River floods, simulation, time series, clustering, streamflow persistence, serial correlation, flood risk.
Recursion formula for unit hydrographs
Authors: Sangal Beni P.
Published: January 2010

A recursion formula has been derived that can be used for either converting short-duration unit hydrographs to long-duration ones or long-duration unit hydrographs to short-duration ones. Thus an alternative to developing an S-hydrograph for this purpose is proposed. Examples on the use of the formula have been provided. Key words: hydrograph, hydrology, S-hydrograph, unit hydrograph, unitgraph.
A cost comparison between conventional and detained drainage systems
Authors: Lee Ken-Beck , Ham Paul
Published: January 2010

Three drainage basins in Surrey, B.C. (sizes ranging from 31 to 102 ha) have been modelled on the basis of both the conventional design method and the design method incorporating detention. The costs for overall drainage systems are then compared. The cost comparison indicates that for the three basins studied the cost advantage would be with the detained system, if downstream erosion and flooding are considered. If these downstream costs are not considered, then the two systems are very similar in cost. Key words: urban hydrology, runoff, detention, storm water management, cost comparison.
Intraprovincial trip distribution model
Authors: Ashtakala Bala , Murthy A. S. Narasimha
Published: January 2010

A town (or city) in a province generates external trips to other towns and cities for various purposes. A cordon origin–destination (O – D) survey shows the origin and destinations of the external trips of a town. An individual external trip distribution model is developed for a town using the cordon O – D survey data. The external trips are recognized as intra provincial trips and therefore the model is called intraprovincial trip distribution model. The data used in this study is taken from cordon O – D surveys done in Alberta.In the formulation of the model, a functional form that uses a linear relationship between the dependent and the independent variables and power transformations on the independent variable is considered. The parameters in the model are obtained by regression analysis. The models are validated by statistical measures and tests. In this paper, an individual model is developed for each of the seven cities and towns chosen for this study. The formulation and development of the model, regression analysis, and validity tests are described in detail. Key words: cordon survey, intraprovincial trips, model, power transformations, regression analysis, trip distribution.
Development of poplar glued–laminated timber. I: Tensile strength and stiffness of poplar laminating stock
Authors: Lepper M. M. , Keenan F. J.
Published: January 2010

The tensile strength and stiffness of 263 full-size pieces of 38 × 80 mm in-grade poplar lumber from two mills in Ontario were determined. Prior to testing, complete maps of all grade-related defects in each piece were made; these defects included general slope of grain, centre knots, and edge knots. Specific gravity and moisture content were also recorded for each piece. After testing, the defects that triggered each piece's failure were noted. This information led, through regression analyses and the assumption of a Weibull distribution, to models for tensile strength and stiffness. The models were developed for the pieces from one mill and were tested against the results obtained from pieces from the other mill; agreement was very good. The knot frequency and slope frequency data were used in a modified form of the Foschi and Barrett glulam beam simulation model to predict the fifth fractile value of a population of poplar glulam beams. Taking the volume effect into account, the predicted beam strengths and stiffnesses are close to those of glulam beams of stress grade 20f–E.
A new concept of upflow clarification in activated sludge separation
Authors: Sparling Arthur B. , Woytowich David L.
Published: January 2010

An experimental investigation was conducted to evaluate a new concept of upflow clarification. A novel sludge removal mechanism that used the entire floor area for the removal of solids was incorporated in an upflow clarifier. The operating characteristics and design features of the continuous flux upflow clarifier (CFLUC) are described in detail. The laboratory study was conducted to determine the effectiveness of the CFLUC clarifier in separating sludges with different settling characteristics. The different sludge types were produced by an activated sludge system treating a synthetic dairy waste at four different food to microorganism (F: M) ratios. At low organic loadings (0.10–0.24 (g COD)(g MLVSS)−1 (d)−1), the CFLUC clarifier removed 70% of the pinpoint floe that remained during quiescent batch settling conditions. At high organic loadings (0.41–0.83 (g COD)(g MLVSS) −1 (d) −1), the CFLUC clarifier was capable of separating filamentous bulking sludges with poor settling characteristics. Based on the results of the experimental study the upflow clarifier effectively separated all sludge types over the range of organic loadings investigated. Key words: CFLUC clarifier, secondary clarification, upflow clarification, sludge blanket, bioflocculation, bulking sludge, gravity sedimentation.
Form drag resistance of two-dimensional stepped steep open channels
Authors: Khashab Ahmed M.El
Published: January 2010

Flow in rough steep open channels is mostly found in mountain streams and in flow overtopping protected weirs. In both cases, the energy of the flowing stream may be dissipated by artificial means so that the flowing water does not result in serious damage due to scour or erosion downstream of the main slope. The best way of achieving this purpose is to lead the flow over a series of steps. In this investigation, the author tried to determine the form drag of stepped steep open channels, considering the steps as two-dimensional triangular roughness elements. Key words: open channel flow, flow resistance, channel roughness, form drag, steep channels.
A relational database for building structures
Authors: Glass Alan J. , Holtz Neal M.
Published: January 2010

This paper looks at some of the requirements of a database for building structure data and the role of the building structure database in an integrated design system. A method of representing the necessary building structure data in a relational database is discussed. The basic data manipulation commands for relational databases are briefly explained. A demonstration database for a steel structure implemented on a microcomputer using a commercial relational database is presented. Key words: computer-aided design (CAD), database, database management system (DBMS), relational database, engineering database, building description.