bluuebunny/crossref_metadata_2025 huggingface dataset:
Colmatage naturel d'un milieu filtrant par les particules en suspension dans l'eau
Authors: Frenette Marcel , Anctil Conrad
Published: January 2010

This paper contains a general study on the natural clogging of porous media by suspended sediment in water. This creates with time a decrease in the permeability coefficient and consequently a reduction of the seepage flow.Two theories are presented and compared for the prediction of the rate of clogging in nature. The two approaches have been verified by experimental data obtained from tests carried out at Laval University. Results have permitted the limits of application of each method to be denned.
Influence of cropping on effective-length factors of tubular steel struts
Authors: Morris G.
Published: January 2010

An experimental investigation is made of the influence of cropping, a relatively new fabrication procedure, on effective-length factors for round tubular steel struts. Tests of 18 companion pairs of cropped and sawn strut specimens, with end plates providing various degrees of end-fixity, are described. The Southwell plot method, using both transverse displacements and strains, is used to determine elastic buckling loads. These are in turn used to compute effective-length factors. Those for the sawn specimens approach 1.0 for very small end-fixity and 0.5 for large end-fixity. Except for the specimens with very small end-fixity, the effective-length factors for the cropped specimens are approximately 15% larger than those for the corresponding sawn specimens.
Limit states design of HSS columns
Authors: Bjorhovde Reidar , Birkemoe Peter C.
Published: January 2010

Hollow structural sections (HSS) have come into increasing usage for structural purposes over the past number of years. There are several reasons for this development, in particular, the advantages of such shapes from an architectural viewpoint, the strength inherent in a closed cross section, corrosion stability, and ease of maintenance. Due to their shape, the members are particularly suited for use as columns.This paper presents a review of typical HSS production methods used throughout the world today, with emphasis on the effect of several important parameters that vary with the production process. Following a general discussion of column strength theory and its application to HSS columns, the development of limit states design procedures for compression members is evaluated. Special attention is paid to the requirements of the standard CSA S16.1-1974, and the studies that led to these rules.Outlining briefly the philosophy of full-scale column testing and typical procedures that are followed in such work, the ensuing portions of the paper present detailed data from experimental and theoretical studies on Canadian-produced HSS sections. Column tests conducted on heat-treated shapes are compared to other data from similar tests on columns produced by a variety of manufacturing processes. It was generally found that the heat-treated shapes performed somewhat better than the cold-formed columns, considered as a whole, and that within the cold-formed data there was considerable variation between manufacturers. Comparison with data from column tests conducted in Japan and in Europe revealed that the Canadian shapes tended to fall within the upper portions of the data band.In closing, preliminary recommendations are presented for the evaluation of the strength of various manufactured HSS members in limit states design.
Electric heating of intake trash racks at Twin Falls, Labrador
Authors: Gevay Bela J. , Erith Henry A.
Published: January 2010

Frazil ice is generated in ‘supercooled’ water upstream of an ice cover, and presents an operational hazard to any water intake for hydroelectric and steam power plants and municipal water supplies.The electric heating of trash racks incorporated in water intakes is one of the recognized methods of preventing the deposition of frazil ice on the racks themselves and the ultimate (if allowed to continue unchecked) complete blockage of the intake. In this paper the authors treat the structural and electrical design and the in-service performance of an electrically heated trash-rack system at the Twin Falls Power Development in central Labrador.The power dissipated in the trash-rack heating system for each 50 000 kW machine was approximately 250 kW, i.e., some 0.7% of unit rating.The Twin Falls rack heating installation gave satisfactory performance over some 12 years of winter operation, since its placement in service for the winter of 1962–1963.
Performance evaluation of an arctic sewage lagoon
Authors: Miyamoto Henry K. , Heinke Gary W.
Published: January 2010

Sewage lagoons are used in several communities of the Northwest Territories, Canada to provide low-cost sewage treatment. Information is sparse, particularly during winter, to prove the effectiveness of this method in arctic climates. The objective of this study was to evaluate the performance of lagoons in arctic regions by a study of the lagoon at Inuvik, N.W.T., over a 1 year period.Results of this study endorse the continued use of sewage lagoons as an effective and low-cost sewage treatment method for small arctic communities. In spite of some serious design and construction deficiencies, and several-fold increase in loading, the Inuvik lagoon has provided reasonable treatment at minimal cost over the past 15 years. Its ability to sufficiently reduce bacterial loads to the receiving stream must, however, be seriously questioned.
Incorporating uncertainty into cost estimates
Authors: Russell S. O.
Published: January 2010

This note presents a procedure for estimating the probability distributions associated with cost estimates. The procedure is approximate but appropriate to the level of detail normally available.
Dimensionnement des tabliers de ponts courants au moyen de l'ordinateur
Authors: Thenoz Marc , Bidaud Claude
Published: January 2010

This paper presents the electronic computer programmes used for the design of standard bridge superstructures by the SETRA (Service d'Etudes techniques des Routes et Autoroutes) of the French Department of Public Works. There is one particular programme for each bridge type. Through these programmes, concrete widths and depths and steel reinforcement are calculated for reinforced concrete beam and slab bridges, and prestressing is designed for prestressed concrete beam and slab bridges.Since February 1, 1962, 11 000 bridges have been designed with these varied and general programmes, suitable for most standard road and freeway overpasses. [Journal translation]
Strain measurements in floating ice platforms and their application to platform design
Authors: Masterson D. M. , Anderson K. G. , Strandberg A. G.
Published: January 2010

The use of the natural ice cover in the Canadian high arctic for offshore petroleum exploration has made possible the drilling of 10 exploratory wells at very reasonable cost. The natural ice is thickened in the loaded area by flooding and freezing in thin layers and required ice thicknesses are obtained using theory for laterally loaded elastic, homogenous plates on elastic foundations. The suitability of this type of theory, which assumes linear strain distribution through the section and a neutral axis at the middle plane, has been questioned, especially since the ice behaves as a visco–elastic material and creeps or strains with time.Resistance strain gauges made of 3 m long, 0.127 mm diameter Teflon-coated wire have been used the last two winters to measure strains in the ice platforms. They have worked well and during the winter and spring of 1978 strains at five different levels in an ice platform beneath the heavier loads were measured and recorded continuously for 62 days. Strain profiles were linear with the neutral axis 0.4 m above the middle plane of the 7.1 m thick platform. Maximum measured principal strains were 1300 με and maximum extrapolated extreme fibre strains were 2100 με, confirming that the strains are small. Stress and effective elastic modulus values are shown to decrease rapidly in the early stages of loading.
A two-continuous-phase sulphur–asphalt composite—development and characterization
Authors: Beaudoin J. J. , Sereda P. J.
Published: January 2010

A two-continuous-phase sulfur–asphalt composite was developed for use as a road repair material. Two methods to obtain a continuous sulfur phase in a continuous asphalt phase are described. Scanning electron microscopy and mercury porosimetry technique provided evidence for a continuous sulfur phase. Mechanical properties—determined from hardness, uniaxial tension, and fracture energy measurements—of the two-continuous-phase sulfur–asphalt composite were studied at 22 and −31 °C. Mechanical properties of fiber-reinforced (up to 2% by volume of dacron fibers) sulfur–asphalt composites were also studied.
Dynamic testing of a modern concrete bridge
Authors: Rainer J. H. , Pernica G.
Published: January 2010

A posttensioned reinforced concrete bridge, slated for demolition, was tested to obtain its dynamic properties. The 10 year old bridge consisted of a continuous flat slab deck of variable thickness having a total width of 103 ft (31.39 m) and spans of 28 ft 6 in. (8.69 m), 71 ft 0 in. (21.64 m), and 42 ft 6 in. (12.95 m). The entire bridge was skewed 10°50′ and the deck was slightly curved in plan.The mode shapes, natural frequencies, and damping ratios for the lowest five natural modes of vibration were determined using sinusoidal forcing functions from an electrohydraulic shaker. These modes, located at 5.7, 6.4, 8.7, 12.0, and 17.4 Hz, were found to be highly dependent on the lateral properties of the bridge deck. Damping ratios were determined from the widths of resonance peaks. The modal properties from the steady state excitation were compared with those obtained from measurements of traffic-induced vibrations and good agreement was found between the two methods.
Design of light industrial buildings
Authors: Nixon Don , Adams Peter F.
Published: January 2010

Even though a large number of light industrial buildings are constructed each year, various problems occur in design for which either little specific research information is available or existing design procedures are overly conservative. This paper is based on an investigation that has as its aims the collection of research information that might be relevant to the design of this type of structure; the modification (where possible) of this information so that it is directly applicable; and finally the formulation of a design guide specifically for light industrial buildings.The investigation is restricted basically to those problems associated with the design of single-storey buildings of structural steel. Topics covered in this paper include cost studies of different structural arrangements, design procedures for girders and columns in buildings with cantilever roof framing schemes, and design procedures for anchor bolts.
Errors in concrete structures
Authors: Allen D. E.
Published: January 2010

One hundred and eighty-eight cases of error in concrete structures, 29 of which resulted in collapse and 118 in distress, deterioration, excessive cracking, spalling, deflection, or settlement, were collected from consulting engineers and government departments across Canada. The survey indicated that about half the errors originated in the design and the other half were due to faulty construction. Most of the collapses occurred during construction, mainly as a result of inadequate formwork or temporary bracing; some were due to detailing errors in design. Most serviceability failures, on the other hand, occurred during use. Many of those failures were due to lack of consideration in design of deflection or of the effects of temperature, shrinkage, and creep.
Computer-aided design of building structures—a guide to data center service in Canada
Authors: Carson Daniel J. , Hartley Gilbert A.
Published: January 2010

The service available from data centers to structural consultants engaged in the design of buildings is reviewed here. This review includes the main hardware provided by the centers, the application software available, and some comments on the support offered for their application software. This information was obtained by purchasing computer time from data centers in the Ottawa area and using their computer programs in hypothetical design situations. This was supplemented by interviews with data center representatives and a study of brochures and manuals published by the data centers. Although the service available is not of consistently high quality right across the board, there are a few data centers that do offer good service to their engineering clients.
Effet du maximum de densité sur la convection libre de l'eau dans une cavité fermée
Authors: Robillard L. , Vasseur P.
Published: January 2010

One of the most important factors affecting the rate of heat transfer by natural convection is the temperature–density relationship of the convecting fluid. The importance of this factor is greatly amplified when the heat is being transferred to a medium that has a maximum density at a given temperature. Water at low temperatures offers such a behavior, its density attaining a maximum value near 3.98 °C. thereafter decreasing with decreasing temperature. This phenomenon is responsible for unusual flow patterns in areas of water exposed to near freezing temperatures.This investigation is a theoretical analysis of the transient natural convection of water contained in a square enclosure with constant wall temperature. Initially the water is assumed to be at a uniform temperature above 0 °C, the wall temperature being suddenly applied.An alternating direction implicit finite-difference schema was used to solve the coupled system of partial differential equations. The transient flow and temperature fields, and local and overall heat transfer are greatly affected by the inversion of flow patterns caused by the maximum density. Their respective values for different flow situations are presented in this study.
A statistical approach to traffic loading on highway bridges
Authors: Harman D. J. , Davenport A. G.
Published: January 2010

A study of the structural effects caused by traffic loading on highway bridges is presented. The objective is to provide guidance for the selection and calibration of the highway live loads, which are specified for design. Bridge loading events with one, two, …, five trucks present are simulated separately in five categories. The results are combined to form a probability distribution for each effect. The idealized trucks used in the simulation procedure are mathematical models of 6380 trucks that were weighed and measured during the 1975 truck survey in Ontario. For each effect, the mean largest value and the corresponding coefficient of variation are calculated based on two traffic densities. The largest effects caused by truck queues in traffic jams are predicted also.The effects are divided into three groups based on their sensitivity to multiple presence. For the first and third groups, the largest effects are caused by loading events with one truck and a queue of trucks respectively. For the second group, loading events with two trucks present may be the dominant cause of large effects. In the calibration process the magnitudes of live loads are adjusted in order that their application causes effects approximately proportional to mean largest effects.
Ferry and roll on/roll off terminal design
Authors: Podolak B. Mark , Khan Ata M.
Published: January 2010

Although a large number of ferry and roll on/roll off services exist in Canada, little research has been carried out on the design of their terminals. In the planning and design of a new or re modelled terminal system, one of the most important tasks is to determine the required number and size of components of the terminal complex. Although advances in design methodology and specific techniques have recently been made for other modal terminals, ferry terminal design has largely been piecemeal and nonscientific. This paper reports a systematic design methodology for ferry and roll on/roll off terminals. In addition to a description of specific techniques developed, design criteria and a case study are reported as well.
Transverse mixing in natural streams
Authors: Beltaos S.
Published: January 2010

The mechanics of mixing of neutral substances in natural streams and methods for engineering applications of the understanding developed to date constitute the subject of this paper.Diffusion and differential advection are identified as the main processes governing mixing in natural streams and are reviewed in some detail. The interaction between these two processes is shown to enhance the rates of spreading in the longitudinal direction and this effect is termed dispersion.Methods for predicting the concentration resulting from injection of a neutral substance in a stream, as a function of time and location, are outlined and the various pertinent simplifications and associated assumptions are discussed. It is shown that in steady-state situations, such as those resulting from continuous releases at constant rate, analytical predictions are possible using a transformation that substitutes distance across the channel by the corresponding fraction of discharge. However, transient mixing, such as that resulting from slug or time-dependent injections, is a relatively complex process and requires use of numerical techniques of computation.A method for generating hydraulic information necessary for applications from limited data is presented. This can be used when detailed hydraulic data are not available or when only limited accuracy of prediction is required.Engineering application is shown to depend on knowledge of the transverse mixing coefficient. In straight, prismatic channels, this reflects the combined effects of turbulent diffusion and dispersion due to secondary currents. However, in natural streams, this coefficient incorporates additional effects, such as transverse dispersion due to helical motions at river bends and river nonuniformity. The former effect has been well documented but virtually nothing is known about the latter.Experimental data regarding the transverse mixing coefficient are reviewed for straight and meandering laboratory channels as well as natural streams. It is shown that the available field data are not sufficient to permit predictions of the transverse mixing coefficient in terms of stream hydraulics. Qualitatively, it can be stated that when the mixing coefficient represents an average value over several meanders, the curvature of river bends appears to be of less significance than had been thought previously and the effect of an ice cover seems to be better accounted for if the transverse mixing coefficient is nondimensionalized with the frictional velocity and the depth rather than the hydraulic radius.Finally, an example of practical application is presented.
Water conservation in the Province of Quebec — at the crossroads
Authors: Demard H. , Dartois J.
Published: January 2010

Saving water or, in a more general fashion, water conservation has won some success in Quebec in the last few years. This article first deals with the types and consequences of drinking water waste and second with the various methods likely to be used in halting it. The possibility of uniting those methods in a policy and the difficulties in doing just that conclude the article.
Limit states design of steel structures—performance factors
Authors: Kennedy D. J. L. , Aly M. Gad
Published: January 2010

A detailed statistical analysis to give ratios of mean to nominal values and associated coefficients of variation (based on raw data collected from Canadian mills on the strength and geometric properties of rolled W shapes, welded W shapes, and class H hollow structural sections) is presented. By relating the tested capacity (based on physical tests performed by others) to the predicted capacity (based on the design equations in CSA standard S16.1-1974, Steel Structures for Buildings—Limit States Design), the professional ratio and its associated coefficient of variation were determined for steel columns as a function of the slenderness ratio, as well as for laterally supported and laterally unsupported steel beams, enabling the performance factor to be determined for these members over the entire range of behaviour. A serviceability criterion for steel bridges is presented.
End moments in open web steel joists
Authors: Shrivastava S. C. , Redwood R. G. , Harris P. J. , Ettehadieh A. A.
Published: January 2010

A study is made of the behaviour of open web steel joists having both top and bottom chords connected to a column when the end is subjected to negative bending moments. Six tests are described, three of which examine the behaviour with typical standard connections as detailed and supplied by manufacturers; the other three involve modifications to these connections in an attempt to minimize connection eccentricity. It is shown that the eccentricities inherent in the standard connections examined can have a significant influence on the behaviour and strength of a joist, whereas if the eccentricities are eliminated, reasonably predictable behaviour, based upon the member resistances under axial loads, can be achieved. These results are examined in relation to tie joists, which are designed to be simply supported under gravity load but have the bottom chord extended and attached to a column, and also in relation to joists designed as framing members.
Resonator studies for Kincardine Harbour, Lake Huron
Authors: James W. , Cuthbert D. R.
Published: January 2010

A 1:600 scale acoustic model of Kincardine Harbour originally built by the National Research Council of Canada (NRCC) was delivered to the Applied Dynamics Laboratory at McMaster University late in 1976. After preliminary testing, a second acoustic model was built to a scale of 1:200 in order to narrow the range of acoustic wave frequencies required to simulate the observed lake wave climate. Scale selection and the necessary acoustic frequency band are discussed. The response at eight locations inside the model harbour was measured in this frequency band and the harbour wave amplification determined. A comparison between the acoustic model results and the hydraulic model results (previously carried out by NRCC) is presented.A public opinion survey of recent users of Kincardine Harbour was carried out during the winter of 1976–1977. The purpose of this survey was to identify potential problems in the harbour. The survey was focused on (a) harbour entrance and resonator, (b) offshore breakwater, (c) rubble-mound breakwater, and (d) inner harbour. The results indicated that the users were generally of the opinion that the resonator had decreased inner harbour oscillations, but that it presented a navigational hazard, particularly at night.On the basis of the survey, a utility function was proposed; it indicates an average condition of the harbour in relation to outside wave conditions. Tests on the acoustic model were then carried out. Results of those tests showed that model beach reflectivity was comparable to that of the prototype, but reflectivity of the model breakwater was relatively low. When resonators were installed wave amplification in the harbour was reduced.
Anaerobic treatment of human waste in northern communities
Authors: Heinke G. W. , Prasad D.
Published: January 2010

Many communities in Canada's northern areas rely on a trucked supply of water and pickup of human waste from bucket toilets or holding tanks. The high capital costs of conventional piped water and gravity sewer systems and the lack of funds necessitate the continued use of trucked systems for many years, particularly in the smaller settlements in permafrost regions. Promising methods of cheaper piped collection of wastes, such as vacuum and pressure sewers, may be used in the near future. Both require only small quantities of water for the transport of solids. Human wastes in plastic bags ("honey bags") are now disposed of at a dump, in waste pits, or lagoons. Satisfactory treatment methods for these strong wastes and for wastes from holding tanks, vacuum, and pressure sewers are needed.Results of a 5 year study simulating a waste pit in permafrost show that it merely serves as a holding tank and does not provide satisfactory treatment. Pathogens are likely to remain viable in such a pit for many years. Anaerobic digestion of undiluted human waste has been found feasible at 20 °C, but is not likely to be a practical and economical solution for communities using trucked systems. Properly located, constructed, and operated waste pits are recommended for these situations.Anaerobic digestion of vacuum sewer wastes, which are much less dilute than sewage, is feasible at a temperature of 20 °C and with a minimum detention time of 30 days. The process may be applicable at lower temperatures, provided a high proportion of methane bacteria is maintained in the reactor. This may be accomplished either by longer detention time or through the anaerobic contact process. It is recommended that a pilot installation be constructed together with a vacuum sewer system in a northern community using anaerobic digestion as the method of treatment of vacuum sewer wastes.
Ice problems at a cooling water intake in a tidal estuary at Lingan, N.S.
Authors: Skarborn Stig , Korol Ted
Published: January 2010

Ice-related design parameters are reviewed as they apply to a saltwater cooling water system for a thermal generating station, located in northern Nova Scotia. Specific areas covered include alternative intake types, ice formation, frazil, ice loads on structures, and partial cooling water recirculation. Recommendations are made as to areas requiring further study.
The design of plain masonry walls
Authors: Ojinaga Jose , Turkstra Carl J.
Published: January 2010

This paper presents a practical method to determine the ultimate strength of plain brick or concrete block masonry walls. Results given by the proposed method are compared with a more rigorous analytical solution, with published test data, and with the current Canadian design code for masonry. Means and coefficients of variation as well as distribution shapes of the ratio of test to predicted loads are estimated from experimental data. Design procedures and simplifications along with two examples are presented.
Recent developments in water pollution control
Authors: Henry J. Glynn
Published: January 2010

Following a brief outline of the status of pollution control in Ontario, the paper examines recent developments in wastewater technology as applied to plant performance, secondary treatment, and sludge processing.Modelling, automatic control, addition of pure oxygen, land disposal, and sludge dewatering are among the new approaches to the design of treatment facilities that are described; their limitations are noted and their application in Canada is considered.Increasing public concern and decreasing resources will force serious consideration of new methods to improve treatment reliability and efficiency. Technology, judiciously employed, can be one of the most effective ways of protecting our environment.
Effet du maximum de densité sur un jet submergé dans une eau en mouvement
Authors: Robillard L. , Vasseur P.
Published: January 2010

A linear relationship between density and temperature cannot be assumed for water near the freezing point. In fact, the density reaches a maximum value near 4 °C and decreases towards 0 °C. The theoretical model of a submerged jet, developed in this report, takes into account this nonlinearity in a very efficient way for the numerical computation. Furthermore, with the general character of the equations used in the model, it is possible to take into account the effect due to the motion of the ambient water. The initial jet orientation being arbitrary, three-dimensional trajectories occur. Results from this model indicate that a submerged thermal discharge is not deflected upward in a sensible way even if its initial temperature is well above 8 °C, but in practice it behaves very rapidly as a sinking jet.
Hydraulic model study for the design of the Wreck Cove control gates
Authors: Weaver D. S. , Martin W. W.
Published: January 2010

An hydraulic model study was carried out to estimate the discharge and downpull characteristics of the vertical lift control gates proposed for the Wreck Cove power project in the Cape Breton Highlands. The same gate geometry was selected with the two different upstream tunnel configurations of the Gisborne and McMillan reservoir–outlet structures. In the former, both free-surface and closed-conduit downstream conditions could occur in the prototype, whereas only closed-conduit flow would exist in the latter. In addition, the gate model was elastically suspended so that its susceptibility to flow-induced oscillations could be assessed. The entire test section was installed in a high-speed water tunnel for testing.The gate-bottom geometry was chosen on the basis of previously reported results with two-dimensional models. The three-dimensional features included in the present model (e.g., gate slots) did not yield downpull or vibration characteristics significantly different from the two-dimensional results. The advantages of the present gate configuration are discussed with respect to simpler but unsatisfactory systems.
Fatigue behavior of steel beams with fillet-welded attachments
Authors: Bardell G. R. , Kulak G. L.
Published: January 2010

Short, horizontally placed plates are frequently welded to beam or girder webs for the purpose of attaching horizontal bracing. In the presence of fluctuating load, this type of detail will influence the allowable fatigue stress range. Current North American specifications have included this detail on the basis of judgement only. The tests reported herein examine the fatigue life of such a detail, including both the influence of the detail and the effect of attaching the bracing members. The results show that the fatigue life is governed by the detail itself and not by the forces introduced by the bracing. They show that the identification of this type of attachment as fatigue category E (Canadian Standards Association) is satisfactory.
Scour problems at railway bridges on the Thompson River, B.C.
Authors: Neill Charles R. , Morris L. Ralph
Published: January 2010

The paper describes the history of riverbed changes and associated pier foundation problems at a series of five bridges along the Canadian National main line in the Thompson River valley of British Columbia. Pier failures were experienced in past years at two of these bridges, and there is a long history of placing rock riprap to combat local scour. The riverbed consists mainly of a thin layer of coarse alluvium overlying consolidated silt and clay.Special investigations conducted for one bridge, including a hydraulic model study, are described in some detail, and various schemes considered for foundation upgrading are outlined. Details are given of a special form of scour protection apron that was installed at one pier.Some research and design implications of the cases described are discussed briefly.
Curvature corrections in open channel flow
Authors: Nasser M. S. , Venkataraman P. , Ramamurthy A. S.
Published: January 2010

A theoretical and experimental analysis of curvilinear flow in open channels is presented. The pressure head coefficient and pressure force coefficient used to account for curvature effects utilizing the energy approach and the momentum approach, respectively, are shown to be related by a simple expression. By virtue of this expression and the relative ease with which the pressure force coefficient is usually obtained, the energy approach can now be readily applied to analyze curvilinear flow problems. Verification of this expression is based on curvilinear flow experiments conducted on simple bottom openings and on available data for the limiting case of a free overfall.
Modèle mathématique de la rivière Koksoak
Authors: Ouellet Yvon , Ropars Yann
Published: January 2010

It is the objective of the present study to determine the general behaviour of an estuary under the reduction of its freshwater discharge. A unidimensional mathematical model, using the finite differences method, has been set up for this purpose. Although this model is very simple and not costly, the output results are quite good. The influence of a reduction of the freshwater discharge upon the tide propagation and the salinity distribution within the estuary is studied. The Koksoak River (now called the Kuujjuaq), which flows into Ungava Bay, has served as model for the present work.One of the goals of the study was to verify if simple geometries, having linear and exponential variations along the river, could be used in the mathematical study of the Koksoak River. Although the present field data are not complete and precise enough to obtain satisfying results of the case under study, i.e., the Koksoak River, general trends are clearly put forward with respect to the comparison between the simulated canals and the river itself. Further field measurements are expected to improve results, which would then predict more accurately the behaviour of this estuary.
Elastic behaviour of composite box girder bridges
Authors: Dalen Karl Van , Narasimham Sanivarapu V.
Published: January 2010

The experimentally observed behaviour of five, one-twelfth scale, wide-flange single-cell composite steel–concrete box girders with both box- and trough-shaped steel sections is described and compared with the behaviour predicted by a folded plate analysis.The folded plate method accurately predicts the elastic strains in such girders when subjected to uniformly distributed load but seriously underestimates the elastic deflections.No significant differences were observed between the structural behaviour of composite box girders with a closed box steel section and girders with a trough-shaped steel section.Aspects of the design of single-cell composite box girders where existing standards result in satisfactory structural behaviour are identified. Tentative design guides are proposed for some aspects of the design of such girders where no guidelines appear to exist at present.
K-joints of double-chord square hollow sections
Authors: Korol Robert M. , Chidiac Magdi A.
Published: January 2010

A new concept utilizing double-chord square hollow sections in welded K-joints of Warren trusses is described. The experimental results of 29 tests are reported, including four connection types: standard, channel, bolted, and back-to-back. The latter type comprised gapped, overlapped, and gapped with connecting stiffener plates.The results indicate that the standard type is an excellent joint in both strength and stiffness. The channel type is generally susceptible to twisting. It was found adequate only when a significant increase in chord thickness[Formula: see text] was employed. The bolted connection appears to hold promise when on-site assembly of large trusses is necessary. Its performance was further improved by connecting the chords with small tie bars. The back-to-back type needed to be reinforced or fully overlapped to develop full branch member strength. The double-chord system of connection reveals itself to be much superior in strength to an equivalent single-chord joint.The effects of eccentricity, branch member chord angle, and chord preloading were investigated. Interaction formulae are presented for the standard- and channel-type joints and their use is illustrated with examples. Satisfactory agreement between predicted and experimental ultimate strengths was obtained for joints that suffered from a chord failure at the connection.
Finite element modelling of jointed structures
Authors: Anis A. H. , Burnett E. F. P. , McNeice G. M.
Published: January 2010

Many engineering problems involve the modelling of discontinuities within continuous systems. As it is difficult and often impossible to obtain a closed form solution a numerical approach must be adopted (e.g., finite element method (FEM)). In studying the panelized problem several FEM models were found in the literature. The primary objective of this note is, therefore, to discuss and compare three FEM models for layered joint response. The specific example that is considered is the panelized concrete wall–floor joint. Joint response is compared using each FEM model at both service loads (for the essentially linear elastic situation) and overload.
Ice action on Nanisivik wharf, Strathcona Sound, N.W.T., winter 1978–1979
Authors: Frederking R. M. W.
Published: January 2010

Field observations have been made over three winters at a vertically faced wharf in an area of limited horizontal ice movement but substantial vertical movement due to tides. Ice thickness was profiled and vertical ice movements were measured. A reasonably consistent pattern of ice behaviour adjacent to the wharf was established, characterized by the formation of a transition ice zone between the first-year sea ice and the wharf. The behaviour and factors affecting growth of this zone are described.
Influence of façade geometry on weathering
Authors: El-Shimi Mahmoud , White Robert , Fazio Paul
Published: January 2010

The results of extensive site observations of weathering patterns (defined as staining, discoloration, or the like) of building façades in a city environment are presented. A primary objective of the research is to determine the relationship between profile variations of precast concrete wall panels, water flow, and resulting weathering patterns. A comprehensive classification of panel shapes arranges panels with common shape characteristics and staining patterns. General categories of projecting frames, flush or punched openings, heavily sculptured, and plain types are analyzed with respect to both large-scale and small-scale staining patterns. An analysis of design details that influence staining patterns is included. Moreover, investigations for a preliminary mathematical model of water runoff over façade surfaces are also described. Finally, a number of pragmatic recommendations are established to guide panel designers.
Aerobic sludge digestion—a suggested design procedure
Authors: Mavinic D. S. , Koers D. A.
Published: January 2010

With high-rate activated sludge as feed, various modes of digestion were studied on a laboratory scale at 20, 10, and 5 °C. This study was performed to develop design guidelines, operating criteria, and kinetic coefficients for low-temperature aerobic sludge digestion. To develop a possible scale factor for extrapolation of laboratory results to full-scale conditions, a field evaluation program was conducted to collect and analyze full-scale data from three independent sources.In this manuscript a summary of previously published data, as well as some of the latest research findings, have been presented. In addition, this paper outlines a new design procedure for use in "sizing" a typical aerobic digester; as well, a method for determination of oxygen requirements in the digester tanks is described.This design procedure is based primarily on a graphical solution involving several variables, whereby the percentage reduction of volatile suspended solids is plotted against the product of temperature and sludge age. Included in this presentation is a comparison between the use (and misuse) of kinetic data in traditional design procedures. The design methodology presented has already proven to be a valuable and cost-effective tool, especially for cold-climate package plant design.
A comparison of design loads for highway bridges
Authors: Buckland P. G. , Sexsmith R. G.
Published: January 2010

Load effects for four bridge design live load models are compared over a broad span range for three simple influence line shapes. The models are American Association of State Highway and Transportation Officials (AASHTO) HS20, Ontario Highway Bridge Design Code (OHBDC), Canadian National Standard CAN3-S6-M78 MS250, and one from the American Society of Civil Engineers (ASCE). Comparisons are made on a number of grounds including maximum effect, simplicity, and accuracy. The span range 30–300 m is considered.
Influence of P – Delta effects on seismic design
Authors: Montgomery C. James
Published: January 2010

The influence of P – Delta effects on the response of buildings subjected to earthquake ground motion is illustrated using time – history studies. It is shown that the influence of P – Delta effects is of great importance for buildings responding in a highly inelastic manner. However, for buildings responding in an elastic or slightly inelastic manner, the influence of P – Delta effects is relatively small. The stability factor approach for estimating the influence of P – Delta effects is reviewed. It appears that this approach gives reasonable results only for systems responding in an elastic or slightly inelastic manner. The strength and drift characteristics of buildings are briefly described. The results presented suggest that the response of certain types of well-designed buildings will not be significantly influenced by P – Delta effects. Finally, recommendations are made for assessing the significance of P – Delta effects for a given building design.
Biochemical oxygen demand–dissolved oxygen mathematical modelling in deep reservoirs with modified water quality for river–reservoir systems model
Authors: Spraggs L. D.
Published: January 2010

Simulation of the dissolved oxygen at the bottom of deep reservoirs using an existing one-dimensional mathematical model is discussed. A modification to the BOD and detrital components is presented and implemented in the mathematical model. A simulation of Boundary Reservoir in Saskatchewan is included to demonstrate the simulative capacity of the modified model.
Snow loads for the design of cylindrical curved roofs in Canada, 1953–1980
Authors: Taylor D. A.
Published: January 2010

Since 1975 recommended design loads on cylindrical curved roofs in the Commentaries on Snow Loads in National Building Code documents have undergone significant changes. This paper presents data and some of the background to the changes, and discusses the problems that have arisen with the recommendations published in the 1977 Commentary. The intent is to make recommended design snow distributions and loads as realistic as possible without undue complication. Further improvements are suggested.
An assessment of CSA standard equations for beam column design
Authors: Pillai S. U.
Published: January 2010

Comparisons are made between results of 81 recent tests on beam columns subjected to unsymmetrical and biaxially eccentric loads and the capacities predicted by design equations recommended by CSA standard S16.1-M78 — Steel Structures for Buildings — Limit States Design. It is concluded that the general provisions of the standard lead to satisfactory designs whereas the detailed procedure given in the Appendix of the standard may lead to a higher proportion of unsafe results.
The design of light industrial buildings — research needs
Authors: Nixon Don , Adams Peter F.
Published: January 2010

In the past decade structural research has concentrated on the design of tall buildings, and has resulted in more rational and economical design procedures for such structures. In contrast, research related specifically to the design of low buildings has lagged somewhat, even though these buildings form a large portion of the market for the steel industry. This paper is a state-of-the-art paper for light industrial buildings in structural steel. Topics covered are loads, economics of different layouts and framing schemes, design of flexural members, design of compression members, and resistance to lateral loads.
Longitudinal stress over supports of concrete box-girder bridges
Authors: Ghali A. , Cheung M. S. , Dilger W. H. , Chan M. Y. T.
Published: January 2010

This paper describes a study of the values of longitudinal moments/stresses and their distribution at sections over the supports of continuous box-girder bridges. A series of continuous box-girder bridges are analyzed using the finite element method. Results from the finite element analysis are compared with the classical beam theory which is commonly used in the design office for this type of bridge. It is found that the use of the classical beam theory assuming knife-edge supports usually results in an overestimation of the support moments. A modified beam-type equation for the support moments is proposed here for the design of continuous box-girder bridges.
Physical mechanics of aufeis growth
Authors: Kane Douglas L.
Published: January 2010

All arctic travelers have encountered streams and braided rivers swollen with ice during the winter months. Numerous field measurements were made in an attempt to develop an understanding of the mechanics of aufeis growth. Piezometers were installed at several sites in central Alaska to measure the pressure variations of the fluid in the porous streambank. Time series analyses were utilized for correlating the variations in the observed pore pressures with climatic variables. It was concluded from the piezometer measurements of pore water pressure that subpermafrost groundwater or groundwater from nonpermafrost regions was the source of water for these ice deposits. Water from the active layer did not contribute to these accumulations of ice. Time series analysis revealed that pore water pressures started to increase following warming trends. A time lag existed between the start of a warming trend and the corresponding changes in pore water pressure; this time lag increased as the thickness of ice increased.
A generalized approach to the deflection analysis of braced frame, rigid frame, and coupled wall structures
Authors: Smith B. Stafford , Kuster M. , Hoenderkamp J. C. D.
Published: January 2010

A generalized approach to the deflection analysis of uniform braced frame, rigid frame, and coupled wall structures is presented. It is shown that these three types of structures belong to a family of cantilevers whose deflections can be defined by their bending and shear characteristics. The deflection equation is written in terms of two nondimensional characteristic structural parameters. Deflection equations are presented for three lateral loading cases: uniformly distributed, triangularly distributed, and a concentrated load at the top.The method is shown to be a useful rapid hand method for estimating deflections, with an accuracy suitable for preliminary design purposes.
Dynamic testing of an open web steel joist floor
Authors: Chan M. Y. T. , Cheung M. S.
Published: January 2010

A non-composite open web steel joist warehouse floor was tested to determine its dynamic characteristics and maximum strain levels under actual operational conditions. Altogether 28 tests were carried out. The strain and acceleration information for each test was recorded on strip chart and magnetic tape recorders. The recorded data were examined and analyzed through a dual channel spectrum analyzer and the results were compared with calculated values. Good agreements are noted.
Prévision des apports hydriques au lac Memphremagog
Authors: Hoang Van Diem , Robert Bruno
Published: January 2010

Within the context of studies concerning water inflow forecasts for some Quebec watersheds, a deterministic hydro-meteorological model, the SSARR (streamflow synthesis and reservoir regulation), was used for Lake Memphremagog near Magog. The low discharge capacity at the outlet of the lake and the obligation to regulate water levels, imposed both by an international agreement and by the wish to protect the environment, had made essential an accurate assessment of runoff during the spring thaw and periods of heavy rain. The results were so conclusive that tests are currently being carried out to prepare forecasts for eight other watersheds in Quebec. [Traduit par la revue]