bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer analysis of thin-walled concrete box beams
Authors: Mavaddat Shahbaz , Mirza M. Saeed
Published: January 2010

Three computer programs, written in FORTRAN WATFIV, are developed to analyze straight, monolithically cast, symmetric concrete box beams with one, two, or three cells and side cantilevers over a simple span or over two spans with symmetric mid-span loadings. The analysis, based on Maisel's formulation, is performed in three stages. First, the structure is idealized as a beam and the normal and shear stresses are calculated using the simple bending theory and St-Venant's theory of torsion. The secondary stresses arising from torsional and distortional warping and shear lag are calculated in the second and third stages, respectively. The execution times on an AMDAHL 580 system are 0.02, 0.93, and 0.25 s for the three programs, respectively. The stresses arising in each stage of analysis are then superposed to determine the overall response of the box section to the applied loading. The results are compared with Maisel's hand calculations. Key words: bending, bimoment, box beam, computer analysis, FORTRAN, shear, shear lag, thin-walled section, torsion, torsional and distortional warping.
Estimating a mode choice model with incomplete data
Authors: Brown Gerald , Kahkeshan Siovache
Published: January 2010

This study develops and uses a synthetic data base to calibrate a logit mode choice model of work trips in metropolitan Vancouver. Missing survey data entries for perceived measures of travel time and waiting time by bus, as well as operating and parking cost by car, are calculated using statistical methods to increase the survey sample of 275 complete cases to 621 usable cases. The synthesized data set is used to specify random utility functions for two planning assumptions. The short-term policy specification using only level of service variables does not produce a usable model, but the specification based on a long-term planning assumption using a combination of level of service and socioeconomic variables produces plausible results. The inconclusive results from the policy model could be due to survey data problems, data simulation, and (or) the lack of conceptual validity of perceived measures of transportation attributes. The planning model provides insight into mode split prediction and transportation management for cities that are undergoing dynamic demographic and social changes. Key words: mode choice, incomplete data, socioeconomic factors, logit model.
Case study of a labyrinth weir spillway
Authors: Tacail François G. , Evans Barry , Babb Alan
Published: January 2010

A labyrinth weir is an effective and economical means of providing increased spillway capacity under some restricted operating conditions. This type of weir is particularly suited to reservoir sites where a low head to high discharge relation is required, the topography restricts the spillway width, and a self-operating structure is highly desirable for emergency operation. Over the past few decades, labyrinth weir spillways have been constructed throughout the world. Definitive guidelines and theoretical procedures pertaining to hydraulic design of this type of weir are not completely established. The designer is confronted with the use of empirical methods for determining spillway configurations which require careful design and verification by use of a hydraulic model. This paper describes the design and hydraulic model study conducted for a labyrinth weir arrangement proposed for the South Heart Dam in northern Alberta. The model study permitted the designers to adopt a more efficient two-cycle weir for the same spillway width as opposed to an initially proposed three-cycle labyrinth weir. Key words: labyrinth weir, spillways, weirs, floods, hydraulic structures, hydraulics.
Connectors for double angles – interconnectors or battens
Authors: Temple Murray C.
Published: January 2010

Recent research on the interconnection of double angles has raised questions with regard to the forces and moments to be transmitted by connectors. It is proposed that when buckling of back-to-back angles occurs in the plane of symmetry, the connector should be termed an interconnector and can be designed for small forces and moments. When buckling occurs in a plane at right angles to the plane of symmetry, the connector should be termed a batten and designed for the shears and moments specified for battens in the applicable standard. Key words: angles, battens, buckling, columns (structural), interconnectors.
Strength and durability of concretes containing 50% Portland cement replacement by fly ash and other materials
Authors: Langan B. W. , Joshi R. C. , Ward M. A.
Published: January 2010

Results are presented from an investigation on the compressive strength and durability of concretes containing substitute materials at a 50% replacement level (by mass) of Portland cement. Seven fly ashes (sub-bituminous, bituminous, and lignitic), together with limestone and an inert material (silica flour), were used as replacement materials. Durability studies included freeze–thaw testing (ASTM C666A), scaling resistance (ASTM C672), and abrasion resistance (ASTM C944). The air void system was assessed using the modified point count method of ASTM C457. The results indicate that although concretes with a 50% replacement level of cementitious material did not perform as well as the control concretes with no replacement, such concretes were able to meet minimum durability requirements. As anticipated, air-entrainment is the overriding factor that allows concrete to meet freeze–thaw durability requirements. In the context of this study, compressive strength does not appear to be a significant factor in freeze–thaw durability. Results indicated that concretes with compressive strengths of less than 10 MPa will still pass the freeze–thaw test, provided an adequate air void system is in place. Abrasion resistance tends to increase with compressive strength but not in all the cases. Key words: concrete, fly ash, compressive strength, durability, mineral admixtures.
Ultimate strength of fillet welded connections loaded in plane
Authors: Lesik Dale F. , Kennedy D. J. Laurie
Published: January 2010

Fillet welded connections are frequently loaded eccentrically in shear with the externally applied load in the same plane as the weld group. While some current design tables are based on ultimate strengths, methods of analysis that incorrectly mix inelastic and elastic approaches are still used. These methods give conservative and variable margins of safety. Design standards generally use a lower-bound approach basing strengths on the longitudinal value neglecting, conservatively, the increase in strength for other directions of loading. The factored resistance of fillet welds, as a function of the direction of loading, is established based on ultimate strength expressions developed herein and using geometric, material variations, and test-to-predicted ratios reported in the literature. Factored resistances of eccentrically loaded fillet weld groups are established. These are basesd on the method of instantaneous centres, ultimate strengths, and the load–deformation expressions developed herein that are functions of the angle of loading. Also, statistical data on geometry, material variations, and the comparison of predicted strengths with the full-scale test results of others are used. Tables of design coefficients giving factored resistances for various eccentrically loaded fillet welded connections are developed. The coefficients, on the average, are essentially the same as those in current design tables. Key words: connections, design tables, eccentric, fillet welds, limit states, ultimate strength.
A pilot-scale evaluation of aerobic–anoxic sludge digestion
Authors: Peddie C. C. , Mavinic D. S.
Published: January 2010

A pilot-scale (300 L) evaluation of waste-activated sludge digestion by a cyclical aerobic–anoxic mode of operation was undertaken at ambient liquid temperatures (14–17 °C). Three experimental runs were conducted over a 2-year period. The first run compared the aerobic–anoxic process to a conventional, continuously aerated, digestion process. During the second run, the aerobic–anoxic digester was compared to a lime-supplemented conventional aerobic process. The third run compared two aerobic–anoxic digester units, operating at reduced (50 and 25% of normal) aeration rates during the aerobic period. In addition, basic data from batch tests are outlined and discussed. Results from the various experimental runs indicated numerous potential advantages for the aerobic–anoxic mode of digester operation. The main advantage was that turning the air on and off resulted in volatile solids reduction efficiencies similar to that in the continuously aerated systems. In addition to the potential for significant savings in aeration costs, another benefit of the intermittent aeration mode of operation involved improved supernatant quality of the final, settled effluent. Key words: aerobic digestion, anoxic, intermittent aeration, lime, pilot-scale, Redox potential, sludge, solids reduction.
Planning and design of passing lanes for the Trans-Canada Highway in Yoho National Park
Authors: Morrall John , Thompson Wayne
Published: January 2010

This paper describes the techniques used in the planning and design of a system of passing lanes for the Trans-Canada Highway in Yoho National Park. The techniques, which include a traffic simulation model, were developed to allow the evaluation of the impact of low-cost operational improvements such as passing lanes on the level of service. The traffic simulation model allowed the investigation of a wide range of highway alternatives in addition to changes in traffic flow, traffic stream characteristics, and vehicle performance characteristics. The passing lane designs described in the paper are based on the concept of incorporating passing lanes within the existing highway cross section. The design concept has evolved from the experimental passing lane project in Banff. In addition to geometric design, signing, and road marking guidelines, warrants for bicycle lanes on the Trans-Canada Highway are also presented. Key words: highway planning and engineering, two-lane highways, traffic simulation model, level of service, passing lanes, Trans-Canada Highway.
Initial cooling of pavements and the development of pavement cooling charts
Authors: White S. , Heiman G. , Huber G. , Besant R. , Bergan A.
Published: January 2010

A relatively short highway construction season exists on the Canadian prairies and typically the paving season extends from May to October. Highway engineers and contractors are continually confronted with unfavorable weather conditions during the early spring and latter parts of the fall paving season. During these periods of cooler weather, the decision as to whether or not to allow paving to continue or begin becomes very difficult, since freshly laid pavements cool quickly and proper compaction is difficult to attain. The final density obtained in a pavement depends critically on its initial temperature and cooling rate. This study researches the subject of pavement cooling and investigates the feasibility of cold-weather paving. The results of this study illustrate the significance of the factors affecting pavement cooling and provide information for improving the paving specifications used by Saskatchewan Highways and Transportation. This study also shows that the short paving season which exists in Saskatchewan can be extended under certain conditions. Extension of the construction season into colder weather will provide financial and various other benefits, not only to Saskatchewan Highways and Transportation but also to paving contractors and the general public. Key words: pavement cooling, pavement temperature, computer simulation, compaction, asphalt concrete.
Étude par éléments finis du comportement à l'arrachement des ancrages injectés dans le roc
Authors: Benmokrane Brahim
Published: January 2010

The uplift behavior of grouted rock anchors is little known despite their increasing use within the last few years and during which their field of application has been greatly broadened. The behavior of anchors is usually controlled at great cost after installation through field tests. Generally, their design is based on experience and an engineer with lesser experience finds it extremely difficult to design one. Furthermore, present methods for dimensioning anchors generally result in oversizing the anchors' grouted length without a corresponding improvement in the safety factor. To provide a more fundamental approach to designing grouted rock anchors, a finite element analysis of the uplift behavior has been carried out. The results of the analysis using isoparametric quadrilateral elements with eight nodes are presented in this article. Results of failure loads and modes obtained from anchors installed in the field are well predicted by the model. Key words: rock mass, grouted anchor, cement grout, finite elements, uplift of an anchor.
Improving shore protection design
Authors: Kamphuis J. William
Published: January 2010

The construction of shore protection is expensive, but the alternative of permitting erosion is also expensive. Yet any design of shore protection is based mostly on intuitive concepts. This paper presents an overview of what is lacking in our knowledge, a possible methodology for improving shore protection design and discussions about some of the most important (and often ignored) physical parameters to be considered if shore protection is to perform its task without interfering with the littoral environment. Key words: erosion, groins, seawalls, sediment transport, shore protection.
Caractéristiques hydrodynamiques d'un estran à forte sédimentation
Authors: Troude Jean-Pierre , Sérodes Jean-Baptiste
Published: January 2010

In the St. Lawrence estuary (Canada), tidal flats localized in the area of saline intrusion are covered with up to 30 cm of fine sedimentation during July, August, and September. This sedimentation is the result of waters coming from the turbidity zone. The upper half of the tidal flats are covered with a tidal marsh. This vegetation is very important in preventing the sediments from eroding. In the tidal marsh, measurements with automatic current meters were taken during periods longer than a month. These showed that, among the vegetation, currents are weak and steady during spring tides and neap tides, whereas next to the drainage systems, currents are heavily dependant on the range of the tide. Close to the shore, currents decrease significantly, thus helping fine sedimentation to occur. A mathematical simulation of the currents made on a line perpendicular to the shore shows the impact of the vegetation on the formation of the drainage system in the tidal flats. Water entrapment by the vegetation at the end of the flood initiates the creation of creeks and insures their continuity throughout the summer. As soon as the vegetation is destroyed, creeks fill up with sediments and disappear from the surface of the tidal marsh. Contrary to what could be assumed, the mathematical model also shows that spring tides, even though associated with strong currents, promote a very active sedimentation on the tidal marsh. In the St. Lawrence estuary, erosion of the mud flats deposits is observed during short periods of strong winds in summer. This high energy and high variability do explain the strong year to year variation in sedimentation observed in the tidal flats. Key words: currents, intertidal sedimentation, tidal creeks, tidal flats.
Fracture and breakup of river ice cover
Authors: Beltaos S.
Published: January 2010

When runoff begins, uplift pressures develop on the underside of the shore fast cover. Analysis shows that longitudinal cracks should form soon after runoff starts. Two cracks are normally predicted, subdividing the cover into a main central part and two side strips. Where ice thickness is large or the channel is narrow, a single mid-channel crack is predicted. Field observations support the theory. With increasing flow, the central portion of the cover may detach and become subject to transverse fractures. The latter could result from bending on vertical or horizontal planes. Vertical bending fracture requires extreme, wavelike slopes such as might prevail briefly during jam releases. Flow shear and the meandering planform of rivers cause horizontal bending manifested in commonly observed transverse crack patterns. The resulting separate ice sheets will be set in motion if there is enough room on the water surface between the river boundaries, thus initiating the breakup. This mechanism leads to a breakup forecasting criterion, called the boundary constraint, that explains past empirical findings and identifies the factors influencing various empirical coefficients. Another type of breakup is caused by ice-jam releases and formation of breaking fronts whereby the ice cover is reduced to rubble before it moves. Little is known about the motion of breaking fronts but relevant field observations are reviewed. Key words: bending, breakup, crack, cover, fracture, ice, onset, release, river, surge.
Disaggregate mode choice models for intercity passenger travel in Canada
Authors: Wilson Frank R. , Damodaran Sundar , Innes J. David
Published: January 2010

Disaggregate mode choice models were calibrated for intercity passenger travel in Canada using a data base drawn from the Canadian Travel Survey. Multinomial logit models were calibrated for business and nonbusiness trips in the eastern and the western regions of Canada. The calibrated models produced reliable results in terms of goodness-of-fit measures. The likelihood ratio index, ρ2(c), varied from 0.282 to 0.436. Results obtained were comparable to those of previous studies. The research identified the significance of level-of-service factors in determining mode choice. The findings from the study indicated that the Canadian Travel Survey data could be used for developing disaggregate models for possible use in policy impact analysis. The potential for the use of this data base in the transportation planning process could be enhanced if some relatively minor modifications were made. Key words: models, disaggregate, choice, intercity, passenger, travel time, cost, frequency, service.
Preliminary report of structural damage from the Loma Prieta (San Francisco) earthquake of 1989 and pertinence to Canadian structural engineering practice
Authors: Bruneau Michel
Published: January 2010

The Richter magnitude 7.1 October 17, 1989 Loma Prieta (San Francisco) earthquake is the largest to occur near a major North American urban center since the historical 1906 San Francisco magnitude 8.3 earthquake. As earthquakes of at least similar strength are expected to occur in most of eastern and western Canada, and since the amount of structural damage that occurred is considerable, the study of the effects of this earthquake is of particular significance to Canada. This paper reports on the major structures and types of structures that were most heavily damaged by this earthquake, and presents preliminary findings as to the causes of failures or collapses. The pertinence of this earthquake is reviewed in a Canadian perspective. Key words: earthquake, structures, damage, failure, collapse, buildings, bridges, heritage buildings, emergency preparedness.
Rupture de barrage et cartographie des inondations, une analyse assistée par ordinateur
Authors: Marche C. , Lessard G. , Lemaire S. , Bouchard B.
Published: January 2010

Considering the increasing number of dams that are ageing, it is important to worry about the safety of these structures and the security of the population that could be affected by the failure of one of them. Computer-assisted engineering allows for the development of more complete computational methods and analysis to assist in these evaluations, and for the establishment of local emergency procedures. Numerical cartography, site data base and interpolation by dual kriging are some of the techniques studied in this paper in order to develop a procedure to determine flooded areas and to monitor their evolution during the rupture of dams. This procedure is applied to a dam built in 1976 upstream of the city of Granby, in Québec. Key words: dam, rupture, flood, numerical cartography, kriging. [Journal translation]
Length effects in 38 mm spruce–pine–fir dimension lumber
Authors: Madsen Borg
Published: January 2010

This paper deals with some of the problems arising when the strength of a structural member varies along its length such as occurs in timber members where knots and other natural growth characteristics create cross sections with varying strengths along the length of the member. Failure may then take place wherever a weak cross section happens to be subjected to high stresses. A different concept of strength must be introduced into the design codes in order to reflect the probability of such an occurrence. Strength becomes a function of length, depth, and load configuration, all of which must be considered in the design process if both economical and safe structures are to emerge. In this paper, which was directed toward establishing the length effects for 38 mm thick spruce–pine–fir in tension and compression as well as bending, the results of a testing program are described. It was, for instance, found that when the length of tension members is doubled from 3.0 to 6.0 m, the strength reduces to 86% of the previous strength, or if the length is quadrupled (as may occur in the bottom chords of trusses), the strength could reduce to 73% of the original strength. A review of the available research information is presented and evaluated in order to assess the adequacy of the available size effect information for design purposes. The present size effect requirements incorporated in some existing timber codes are also reviewed. Key words: timber, strength, size effects, length effect, weakest link theory, design method, load configuration, bending, compression, tension.
Size effects in defect-free Douglas fir
Authors: Madsen Borg
Published: January 2010

This paper describes experimental work on size effects occurring in defect-free Douglas fir and suggests empirical methods for modelling these. It was found, contrary to present belief, that the size effects could best be described as a volume effect. It was also found that wet and dry materials behaved very differently with respect to size effects. Defect-free material represents the stronger and more expensive range of materials available to the structural engineers. It is, therefore, important that the material behavior be better understood in order to create structures that are both safe and economical. Key words: size effects, clear wood, defect-free wood, volume effect, length effects, load configuration effect, moisture content, weakest link theory.
Wave forces on a pipeline in a trench
Authors: Skafel M. G. , Bishop C. T.
Published: January 2010

Wave forces on a model pipeline have been measured. The pipeline was located in a trench, the configuration of which is similar to that proposed for oil and gas production in the Beaufort Sea. It was found that the drag and inertia coefficients were similar to the results reported in the literature for flat beds, assuming the water depth was that of the total water column including the trench. Flow visualization tests confirmed that the horizontal velocities were about the same as those that would be found on a flat bed with the same total depth. Key words: wave forces, pipelines, trenches.
Evaluation of IRD-WIM-5000 — a Canadian weigh-in-motion system
Authors: Sharma Satish C. , Stamatinos George , Wyatt John
Published: January 2010

The analysis presented in this paper deals with the accuracy of a weigh-in-motion (WIM) system installed on Trans-Canada Highway west of Regina. Spot speed data collected by the WIM system are compared with the measurements taken by a radar meter; the WIM data on axle spacing are compared with data obtained by manual measurements; and the dynamic weight data gathered by the WIM system are evaluated against static weights. The following conclusions can be made from this study: The WIM system under investigation provides accurate data for spot speed and axle spacing. The study data for 88 trucks indicate that the dynamic weights recorded by the WIM system may contain high magnitudes of both systematic and random errors. However, the results of analysis presented indicate that a proper calibration of the system can reduce the systematic errors to a large extent and produce results that may be satisfactory for a number of highway planning and design functions. Key words: axle spacing, dynamic weight, highways, static weight, traffic studies.
Numerical modeling of pressure-reducing valves in water distribution network systems
Authors: Panu U. S.
Published: January 2010

Computer models are no longer viewed as exotic luxuries, rather they are being increasingly accepted as necessities for effective planning and operation of water distribution systems. In large networks, pressure-reducing valves (PRVs) are common water appurtenances. However, through the use of the Hazen–Williams friction factor, there are difficulties in representing PRVs in network-analysis models. This paper focuses on these difficulties and suggests a procedure for resolving them through the use of modified Hazen–Williams friction factor. The effectiveness of the proposed modification in representing PRVs in the WATER model is demonstrated. Key words: network analysis, numerical modeling, hydraulics, municipal, water distribution, PRV representation, friction coefficient, Hazen–Williams, flow rate, simulations.
Hydraulics of culvert fishways III: weir baffle culvert fishways
Authors: Rajaratnam N. , Katopodis C.
Published: January 2010

This paper presents the results of a laboratory study of culvert fishways with weir-type baffles. Baffles with heights equal to 0.15 and 0.1 times the diameter (D) of the culvert were studied with longitudinal spacings of 0.6D and 1.2D. Equations have been developed to describe the relation between the discharge, slope, diameter, and the depth of flow. It has been possible to predict the barrier velocity that would exist at the baffles. The performance of the weir baffles has been found to be as good as that of the slotted-weir baffles. Key words: culverts, fishways, hydraulics, turbulent flow, open-channel flow.
Variances and covariances of the maximum entropy estimators for the Pearson type-3 distribution
Authors: Phien Huynh Ngoc , Nguyen Van-Thanh-Van
Published: January 2010

Although the method of maximum entropy (MME) appears to be promising in fitting the Pearson type-3 distribution, the sampling properties of the estimators are not available. This paper provides the formulas needed for computing the variances and covariances of the parameter estimators and the variance of the T-year event. All needed formulas are derived analytically and related computation schemes are described. Through applications of the developed technique to actual and simulated data, it was found that the efficiency of the MME may be slightly improved when the biased sample variance is used instead of the unbiased one. Key words: Pearson type-3 distribution, method of maximum entropy, floods, statistical hydrology, Monte-Carlo simulation.
Heat and mass balance of an ablating ice jam
Authors: Prowse Terry D.
Published: January 2010

This paper reports on the heat and mass balance of an ablating ice jam at the confluence of the Liard and Mackenzie rivers in the spring of 1983. From May 6 to May 9, sufficient data were collected to determine the magnitude and relative importance of the major heat fluxes that caused thermal decay of the ice jam. The total atmospheric heat input of 1.25 × 108 MJ and the much larger contribution from hydrothermal sources of 9.80 × 109 MJ resulted in a total melt of 3.24 × 107 m3 of ice within the jam. These data in combination with previous results regarding jam dimensions permitted calculation of ice jam porosity, a variable frequently used in hydraulic studies of river ice jams although unverified by field data. The largest potential error in the calculations was related to the accuracy of water temperature measurement. Accounting for this resulted in an estimate of porosity of 0.38 ± 10% which lends credence to the commonly assumed value of 0.40. Details of the field conditions, instrumentation, theoretical methods, and results of the energy and mass balance analyses are described. Key words: floating ice, ice breakup, ice jams, ice melt, ice porisity.
Using queue distance to supplement traffic signal timing design
Authors: Lu Yaean-Jye , Luh John Z. , Yep Alan K.
Published: January 2010

A common approach in traffic signal timing design at isolated intersections is to assume homogeneous traffic flows and ideal geometric conditions, and then to apply adjustment factors so that variations from the ideal conditions are considered. Since the ideal and adjustment values are usually developed from empirical field data, the final result may not accurately reflect the true local situation. Fine tuning, primarily based on personal judgment, is therefore almost always required because local conditions differ from study conditions. This paper presents a method which relies solely on an empirical traffic factor, namely queue distance, to determine the green time. Field surveys at three intersections were conducted to establish the equations used in this method. The coefficients of the equations are interpreted. The applications of this method to supplement the fine tuning are presented. The potential application of this method on traffic responsive control is also proposed. Key words: traffic signal, queue, regression analysis, pretimed signal, traffic responsive control.
Earthquake resistant design of steel moment resisting frames
Authors: Redwood R. G. , Lefki L. , Amar G.
Published: January 2010

New provisions of the CSA Standard for Steel Structures (CAN/CSA-S16.1-M89) dealing with detailing of moment resisting frames for seismic design are described and related to requirements of the National Building Code of Canada. The basis of the new requirements is outlined, and an example eight-storey frame is used to illustrate the impact of the provisions. Key words: design, structural engineering, steel, earthquakes, moment resisting frame, standards.
Behaviour and design of coupled slab–structural wall systems
Authors: Mirza M. Saeed , Lim Albert K. W.
Published: January 2010

This paper presents the results of tests on nine reinforced concrete slab-coupled structural wall subassemblages subjected to gradually applied reversing displacements simulating earthquake loadings. Two-third scale direct models of Taylor's Specimen No. 1 were used to study the effect of the following parameters in three phases: Phase 1, the effect of providing stirrups around the longitudinal slab steel; Phase 2, the effect of providing shallow reinforced concrete longitudinal and transverse concealed beams; and Phase 3, the effect of providing longitudinal drop panels. The experimental behaviour of the specimens is reviewed and discussed and suitable design recommendations are presented for strength and stiffness of slab–structural wall systems along with some practical guidelines to control damage in the coupling slab at higher levels of imposed deformations. Key words: coupled reinforced concrete slab–structural wall systems, damage, degradation of strength and stiffness, ductility ratio, earthquakes, gradually applied reversing displacements and loads, punching shear failures, reinforcement details, shallow coupling beams, yield lines.
Development of a portable direct filtration water treatment plant in northern Manitoba
Authors: Markowsky John W. , Woytowich David L. , Goulter Ian C.
Published: January 2010

The Limestone Generating Project was reactivated in 1985. Part of the development of the project was to review and implement, if feasible, potable water treatment facilities for the construction community of Sundance. The source water, from the Nelson River, is of reasonably good quality. The turbidity, however, ranges from 4 to 70 nephelometric turbidity units (NTU), averaging 15.2 NTU. Following preliminary and pilot plant studies, a high rate, deep bed direct filtration system was proposed and constructed to reduce turbidity to acceptable levels. A key feature of the plant is its portability. Owing to the innovative design, the three filters can be easily transferred for use at future construction sites on the Nelson River. This paper reviews and discusses the design, construction, operation, and costs of the plant. Key words: construction, design, direct filtration, high rate, Nelson River, operation, portability, turbidity.
Modelling of settling and flocculation of fine sediments in still water
Authors: Krishnappan B. G.
Published: January 2010

A numerical model to predict settling behaviour of fine sediment mixtures in a stagnant water column is described. Both single-grain settling mode and the floc settling mode are considered. The single-grain settling mode is analyzed by solving the unsteady, one-dimensional diffusion–advection equation numerically and the floc settling mode is examined by solving a coagulation equation expressed as a discrete equation in logarithmic radius space considering the differential settling as the only collision mechanism. The model results are compared with the laboratory experimental data of K. Kranck for both modes of sediment settling. The agreement between the model predictions and the experimental data is good. The model can be used as a basis for such practical applications as predicting sedimentation rates in reservoirs and settling basins. Key words: sediment mixtures, settling, flocculation, advection, diffusion, floc size distribution, primary particles.
Floor vibrations from aerobics
Authors: Allen D. E.
Published: January 2010

Recent vibration problems with floors used for aerobics have shown the need for better guidelines for structural design and evaluation. Such guidelines were introduced for the first time in the Supplement to the 1985 National Building Code (NBC), but more recent experience with one particular floor has shown the need for some improvements to these guidelines. The paper describes the investigation of the floor and the use of the floor to estimate the loading function for aerobics, and recommends changes to the NBC design criteria. The paper provides guidance on estimating parameters used in the criteria and discusses repair alternatives related to the floor problem. Key words: floor vibration, aerobics, design criteria, repair.
W-shape beam to RHS column connections
Authors: Dawe J. L. , Grondin G. Y.
Published: January 2010

Tests on full-scale connections between wide flange beams and rectangular hollow section (RHS) columns reveal various modes of failure as a function of connection geometry. Tension and compression moment plates with web clip angles or tension plates and seat angles welded to doubler plate reinforced RHS walls are investigated. Eight failure modes were identified from an experimental program consisting of ten full-scale specimens. Semi-empirical expressions based on assumed stress distributions predict failure modes and corresponding moment capacities reasonably well for various connection configurations. Further analytical parametric studies showed the importance of tension plate and doubler plate dimensions on joint strength and behaviour. Key words: RHS, W-shape, columns, beams, connections, experimental, analytical, design, steel.
The San Francisco area earthquake of 1989 and implications for the Greater Vancouver area
Authors: Rainer J. H. , Jablonski A. M. , Law K. T. , Allen D. E.
Published: January 2010

The earthquake that hit the San Francisco area on October 17, 1989, is reviewed with respect to damage to buildings, transportation facilities, and services. The San Francisco experience underlines that soil conditions and inadequate structural integrity are the two most important factors in the seismic risk to a building and its inhabitants. This earthquake is used as a model for the damage prediction in the Greater Vancouver area from a "design earthquake" that is implied in the National Building Code of Canada. In comparable housing density the expected damage would be somewhat greater than that observed in the San Francisco region in October 1989 because of differences in amplitude of ground motions and building design standards. This study is seen as a first step in the detailed assessment of damage potentials for the Vancouver region, or other similar metropolitan areas. Potential shortcomings in the 1985 National Building Code of Canada were identified in the seismic requirements for non-engineered buildings (Part 9) concerning lateral bracing, beam splice ties over supports, and anchorage and reinforcing of chimneys. Key words: earthquake damage, building code, damage prediction.
Damage to buildings due to the 1989 Loma Prieta earthquake — a Canadian code perspective
Authors: Mitchell Denis , Tinawi René , Redwood Richard G.
Published: January 2010

Damage to building structures during the October 17, 1989, Loma Prieta earthquake prompted site visits by the authors. This paper presents examples of damage to buildings constructed with reinforced concrete, steel, masonry, and timber. The observed damage is used to illustrate some of the seismic design clauses in the 1990 National Building Code of Canada, the 1984 Canadian Standards Association (CSA) Standard for the Design of Concrete Structures for Buildings, and the 1989 CSA Standard for the Limit States Design of Steel Structures. The important roles played by the presence of soft soil, poor structural layouts, inadequate detailing, the lack of reinforcement in masonry, as well as inadequate connections to foundations are highlighted. Examples of the performance of upgraded structures are also given, and the concern over the presence of existing hazardous buildings in significant seismic zones in Canada is emphasized. Key words: seismic design, earthquake, Loma Prieta, structures, codes, concrete, steel, masonry, timber, upgrading.
Strengthening of wide-flange columns under load
Authors: Marzouk H. , Mohan S.
Published: January 2010

The present work deals with formulation of theoretical and analytical methods leading to the development of column strength curves. The formulations were developed for both elastic and inelastic behaviour. Two types of reinforcement have been developed for strengthening the W-shape columns under load. Since the column strength curves are based in part on the magnitude and distribution of residual stresses, it is extremely important to consider the new pattern of residual stresses due to welding process. Also, the welding sequence will affect the magnitude and distribution of residual stresses. Theoretical formulations leading to a closed-form solution for the prediction of critical load were developed for two types of strengthening using the superposition of original residual, new welding, and initial loading stresses. A nonlinear finite element analysis based on the large deformation theory of stability was used to predict the strengthened column critical load. It takes into consideration the effect of cooling residual stresses and new welding residual stresses. The formulations were incorporated with gradual penetration of yielding, the spreading of inelastic zones along the member length, the presence of residual stresses, and strain hardening of the material. Experiments were carried out to determine the actual capacity of strengthened columns. Seven specimens were tested using two and four strengthening plates. The welding stresses were measured through a series of experiments, and it was found that the parabolic distribution is a very close approximation to the actual new welding stress distribution. Key words: reinforcement of steel columns, welding stresses, welding sequence, strengthening of existing structures, buckling, steel plating, finite element.
Modelling of low-temperature behaviour of cracks in asphalt pavement structures
Authors: Selvadurai A. P. S. , Au M. C. , Phang W. A.
Published: January 2010

This paper examines the transient stress analysis of a multilayer pavement structure subjected to heat conduction and associated thermoelastic effects by the cooling of its surface. In particular, the layered structure contains a transverse crack which can be created either during the construction of the pavement or during its service life. The numerical treatment of the transient stress analysis is achieved using a finite element scheme, which models the heat conduction and thermoelasticity of each component in the layered system and the singular stress field at the extremities of a crack. The numerical scheme is applied to examine the manner in which the propagation of an existing crack is influenced by the thermoelastic mismatch between the layers adjacent to the crack location. The analysis also illustrates the influence of the thermoelastic mismatch between a cracked pavement and an overlay, in the suppression of crack propagation. Key words: fracture mechanics, pavement structures, low-temperature fracture, transient thermal effects, finite element modelling, stress intensity factors.
Shearing off the lower section of an existing column
Authors: Marzouk H.
Published: January 2010

The present investigation deals with the removal of the lower portion of a glued laminated column in an existing uranium industrial processing plant in Saskatchewan, Canada. The lower 8 m of the column was eliminated to avoid transmission of high dynamic magnification forces created from installing a new rod mill in the crushing area of the plant. The construction details of transferring and securing the building column loads to the adjacent concrete wall and new steel trestle are examined. Some design aspects of a new built-up girder and other supporting elements are discussed. A summary of the construction procedure employed is given, which would be extremely valuable in similar structural alteration or rehabilitation jobs for old industrial plants. The construction of a new mill and the structural alterations were carried out during the spring of 1984. Since then, the new mill and the existing structure have performed satisfactorily. Key words: shearing existing column, rod mill, rehabilitation, built-up girder, structural alteration.
Réponse d'une chaîne de traitement biologique des eaux usées à des apports de ruissellement urbain
Authors: Couillard Denis
Published: January 2010

During periods of rain, combined sewer systems carry urban runoff water to sewage works. Urban runoff water is different, however, from household wastewater — the usual influent of wastewater treatment systems — especially the flow and the concentrations of suspended solids and metals. The purpose of the research described herein was to examine potential effects of runoff water on a treatment system to find out if major damage to the system is likely to result from input of urban runoff. The literature on urban runoff and on qualitative, toxic, quantitative, and hydraulic shocks was reviewed, and the knowledge gained was applied to a case study based on real data collected from metropolitan Quebec City (Canada) in June 1985. Experimental data indicate that the recorded variations in flow and in quantities of suspended solids, organic matter, and nutrients in the combined system following various rain events would not dramatically affect operation of a wastewater treatment system. The same conclusion applies for the increase in concentrations of copper and zinc. Further research on qualitative shock and the impact of the increase in the concentration of lead is required. Key words: biological treatment, waste waters, quality, concentration, rainfall, urban runoff waters, shock loads, toxics. [Journal translation]
Lateral load response of unbraced steel building frames
Authors: Sivakumaran K. S.
Published: January 2010

The standard CAN3-S16.1-M84 "Steel structures for buildings — limit states design" recognizes three sets of assumptions in the analysis, design, and construction of steel buildings. In two of them the connections are assumed to be either fully rigid (continuous construction, clause 8.2) or completely free (simple construction, clause 8.3.1). In the third type of construction, termed here as "special simple construction" (clause 8.3.2), the beam-to-column connections are assumed to be completely free (pinned) to resist gravity loads and are assumed to be rigid to resist the lateral loads due to earthquake or wind. Such connnections are designed for moments due to lateral loads only, and thus they are more flexible and may yield at ultimate load levels. This paper illustrates the analysis and design of two (one 5-storey and the other 10-storey) office buildings assumed to be located in Hamilton, Ontario, on the basis of special simple construction. Using realistic connection behaviour, the influence of connection flexibility and strength on the performance of these buildings is studied. In the nonlinear static analysis, the buildings have been subjected to gravity loads and incremental lateral loads until failure. For comparison purposes, the building frames were also analysed and designed, based on continuous construction assumptions. The results showed increased drifts and decreased overall strength due to connection flexibility and strength. Thus, the system based on continuous construction structurally performs better than the system based on special simple construciton. As far as the economy is concerned both systems appear to be equivalent. Key words: building design, steel structures, flexible connections, analysis, wind load, earthquake load, strength.
Design of crane runway girders for top running and underrunning cranes and monorails
Authors: Goldman Carl
Published: January 2010

This paper contains a review of crane characteristics such as speed, wheel loads, and runway tolerances. A review of the rails and fastening is made. The paper presents the design of runway girders and a discussion on the selection of various sections or built-up members. A comparison is made between various specifications for impact and fatigue loading. Deflection tolerances and long spans are discussed. Details of supports at columns are presented and discussed, in particular, poor details causing failure as well as those that have performed well over many years. This paper is useful for structural engineers designing heavy industrial structures. Key words: crane characteristics, runway girder design and supports.
Multi-chute systems for high-rise apartment recycling
Authors: Attieh Ibrahim , Baetz Brian
Published: January 2010

The concept of a multiple chute system for waste material recycling in high-rise apartment buildings is introduced and discussed. The proposed system is compared with the existing schemes for apartment recycling, and the economic feasibility of a multiple chute system is considered for a wide range of conditions. Key words: material recycling, waste management.
Knowledge-based systems and operational hydrology
Authors: Simonovic Slobodan P.
Published: January 2010

Knowledge-based systems were brought to the attention of hydrologists almost a decade ago. The application of knowledge-based systems technology is natural and appropriate for the field of hydrology because it contains numerous procedures developed from theory, actual practice, and experience. The emphasis of the present paper is on demystifying knowledge-based systems of artificial intelligence. After a detailed review of the most important applications to the field of hydrology, the original concept for applying knowledge-based technology is presented. The discussion ends with the list of possible benefits from the application of knowledge-based technology. An expert system for the selection of a suitable method for flow measurement in open channels is used as a case study to illustrate the discussion in the paper. The system has been designed for potential use in Environment Canada. Key words: expert system, water resources, hydrology, flow measurements.