bluuebunny/crossref_metadata_2025 huggingface dataset:
Sludge management by thermal conversion to fuels
Authors: Campbell H. W. , Bridle T. R.
Published: January 2010

The philosophy of sludge management in the sewage treatment industry must respond to changes in processing costs and environmental requirements. As overall costs increase, the efficiency of sludge management must be increased either by ugrading the existing scheme or introducing new technology. Both of these approaches are discussed briefly in the paper and it is pointed out that low-temperature conversion of sludge to fuel appears to have considerable potential as a viable new technology.Experimental work carried out at Environment Canada's Wastewater Technology Centre used batch and continuous reactors to evaluate this technology at bench scale. Tests on a number of mixed raw sludges (primary + waste activated) resulted in the following yields: oil, 22–25%, char, 50–60%, noncondensable gas, 10–12%, and reaction water, 5–12%.The impact of a number of sludge treatment alternatives, including the conversion of sludge to oil, are discussed with respect to energy efficiency, flexibility, and public acceptance. The future plans of Environment Canada for the development and demonstration of sludge-to-oil technology are also discussed. Key words: sewage sludge, thermal conversion, energy recovery, sludge management, oil, fuel, char.
Effective widths of composite beams with ribbed metal deck
Authors: Elkelish S. , Robinson Hugh
Published: January 2010

The effective width of the concrete slab of a composite beam is used in the determination of its moment resistance and service load moment for the purposes of structural design of the composite beam. It is usually assumed that the same effective width of the concrete slab may be used for both ultimate strength and elastic stage calculations.This paper presents the results of an analytical investigation of the variation of the effective width of composite beams and ribbed slabs formed by ribbed metal deck in both the elastic and inelastic stages and at ultimate load. A layered finite element method is used to model the composite beam. The influence of four variables on the effective width of the composite beams was studied, namely, type of loading, beam span to actual concrete slab width, ultimate compressive strength of the concrete, and steel beam size.It was found that the effect of the compressive strength of the concrete and the size of the steel beam have negligible influence on the effective width of the concrete slab. The effective width of the slab at ultimate load is of the order of 4% larger than that in the elastic range.The effective width used for the design of composite beams under a uniformly distributed load, which is the practical loading in most cases, is significantly different from that which should be used for any other type of loading.
Torsional axisymmetric finite element model for problems in elasticity
Authors: Lau Ming G.
Published: January 2010

This note describes how the displacements and shear stresses of an axisymmetric elastic component, when loaded in torsion, can be computed by modelling the component with torsional axisymmetric finite elements. The model developed represents only minor modifications of the well-known plane stress or plane strain finite element technique.In the analysis, the model is split into a mesh of triangular annuli. Each node of each element has only one degree of freedom, the tangential displacement. The state of strain in each element is represented by a three-term displacement function, one representing a rigid body rotation, the second representing the state of torsion, and the third representing the state of strain in a hollow thin disc.The model has been applied satisfactorily to three torsional problems with known theoretical solutions. The first problem involves the computation of torsional shear stresses of a uniform shaft subjected to pure torsion. In the second problem, the solution is obtained for a conical shaft. In the third problem, known as the Reissner–Sagoci problem, an elastic semi-infinite medium is subjected to a torsional displacement on a small area of the surface.A typical application of the model to the problem of a shrink-fitted assembly subjected to torsion is discussed. Key words: torsion, finite element, elasticity, axisymmetry.
Preliminary assessment of a shortcut in nitrogen removal from wastewater
Authors: Turk O. , Mavinic D. S.
Published: January 2010

The objective of this long-term research project was to demonstrate the feasibility of removing nitrogen from highly nitrogenous wastewater by (a) blocking the nitrification process at the intermediary nitrite level through the action of free ammonia and (b) subsequently reducing the nitrite to nitrogen gas. The success of such a process could lead to substantial reductions in nitrogen removal costs.Two identical bench-scale activated sludge systems were operated for 147 days, in the initial phase. Each system was composed of four equal-sized, completely mixed cells in series. The free ammonia concentration was highest in the first cell of each system. It averaged 2 mg NH3-N/L in the first system and 5 mg NH3-N/L in the second. Nitrite buildup, in excess of 80% of the oxidized nitrogen present, was induced and sustained for around 2 months in all cells of the second system, after which time a steady decline occurred. Nitrite buildup could not be sustained in the first system. Average chemical oxygen demand (COD) for nitrite reduction was 40% lower than that for nitrate reduction. The nitrification rate for the ammonia oxidizers was similar for both systems. The presence of up to 100 mg [Formula: see text] nitrite in system 2 caused no discernible inhibition. Subsequent runs proved that nitrite accumulation could not be sustained indefinitely, owing to acclimation to free ammonia levels as high as 22 mg NH3-N/L. Periodic resting and flushing may be required; further research is being pursued along these lines. Key words: biological treatment, denitrification, nitrification, nitrite, nitrogen removal, nitrogenous wastewater.
Interconnection of starred angle compression members
Authors: Temple Murray C. , Schepers J. Albert , Kennedy D. J. Laurie
Published: January 2010

The requirements for the interconnection of starred angle compression members contained in North American standards vary greatly from those of European standards. The North American standards, which require only one interconnector for any starred angle made with equal leg angles, are the most liberal. The British standard, on the other hand, is the most conservative.A theoretical study of "slender" starred angles indicates that the buckled shape changes when the number of interconnectors is increased from one to two. There is a corresponding increase in the critical load. The addition of more than two interconnectors has no significant effect on the critical load. An extensive experimental program verified these results. The experimental program also included starred angles that could be classed as being of "intermediate" length.The paper recommends that two interconnectors be used, one at each of the third points, in all starred angle compression members made with equal leg angles. Key words: angles, buckling, building (codes), columns (structural), design, interconnector, starred angle.
Indice de qualité de l'eau pour détecter l'impact de la pollution diffuse urbaine
Authors: Couillard Denis , Lefebvre Yves
Published: January 2010

This study fits into the scheme of research work being carried out to control stormwater rejects. Its main objective is to represent, with the help of a water quality index, the deterioration of the quality of the Saint-Charles River, caused by the combined sewer overflows of Quebec City, Canada, during a rainstorm. The proposed quality index has been applied to evaluate the recreational use of the river.The overall results obtained in the case of a 20 mm rain show index values that characterize a water of poor quality. Moreover, within the region of the combined sewer overflow, a minimum delay of 24 h is necessary to allow the water quality of the Saint-Charles River to return to the level where it was at the dry period, which generally has a value less than the critical value for recreative use. Key words: water quality index, urban runoff, water pollution, nonpoint source of pollution, water quality, water use, environmental impact, pollution control.
Ice jam characteristics, Liard–Mackenzie rivers confluence
Authors: Prowse Terry D.
Published: January 2010

Breakup of the Liard and Mackenzie rivers near Fort Simpson, N.W.T., was monitored from 1978 to 1984. In each year, ice jams ranging in length from 10 to 22 km formed at the Liard River mouth. Although the thickness of some of the jams exceeded 5 m, the volume of ice within the accumulations represented less than 20% of the ice contained within the pre-breakup ice cover of the Liard River main stem. The composition and thickness of the ice jams was related to whether breakup was a 'thermal' or 'mechanical' event. The majority were mechanical breakups and produced much thicker jams and higher water levels than did thermal breakups.Stage–discharge rating curves were developed for the site using two appoaches based on the equilibrium jam theory. The first employed jam parameters calculated for the 1983 jam and the second used a simplified approach suggested by S. Beltaos. Both approaches predicted stage increases of approximately 4–8 m above that which would result from similar discharge under open water conditions. Furthermore, the first approach resulted in a coefficient of internal friction of 1.06, supporting the suggestion that this parameter may have a mean value of 1.2. Key words: floating ice, floods, ice jams, ice breakup.
The effect of confinement on lap splices in reversed cyclic loading
Authors: Sparling B. , Rezansoff T.
Published: January 2010

Twelve large-scale tests (7 m beams with 30 mm main reinforcement) were made to investigate the performance of lap splices in reinforced concrete beams subjected to reversed cyclic loading which produced yielding in the main reinforcement. Load history and various configurations of splice confinement were the major parameters considered. Performance was judged on the basis of strength, ductility, and several degradation indicators.Behavior was dependent on the degree of splice confinement. Specimens containing superior splice confinement, provided either by closely spaced stirrups or by closely fitting spirals, were more ductile and sustained more load cycles, on average, prior to failure. It was advantageous to provide more splice confinement than the amount considered to be effective under static loading. Tensile splices designed with superior confinement according to proposed seismic specifications achieved ductility ratios (failure deflection divided by first yield deflection with no splice) which averaged 2.66.Reversed cyclic loading was more damaging than repeated unidirectional or monotonic loading. The number of reversed load cycles to failure decreased as the intensity of loading increased. Under load reversals, the reduction in stiffness, the increase in energy dissipation, and the gain in damping capacity were used to examine the degradation that could be sustained before failure. Key words: reinforced concrete, beams, bond, splices, cyclic loads, ductility, seismic design, joints, deflection, strength, stiffness, damping.
Differential movements and stresses in high-rise masonry veneers: Analysis
Authors: Fenton G. A. , Suter G. T.
Published: January 2010

In recent years a growing number of masonry veneer distress cases have occurred on high-rise structures. These cases are now known to be caused by the omission of a differential movement joint between veneer and structure. This paper reviews how these distress problems have arisen in a historical context and then presents the various movement parameters and relationships that must be considered. A computer model was developed to predict differential movements and resultant stresses when inadequate movement joints are provided. The paper gives an overview of the model and describes its capabilities. The application of the model to a case study structure is treated in a subsequent paper.
National aviation museum, Ottawa
Authors: Adjeleian J. , Allen M. , Humar J. L. , McRostie G.
Published: January 2010

This paper describes various aspects of the design and construction of a new building for the National Aviation Museum, currently nearing completion on a site on the Rockliffe Airport, Ottawa. The museum will house the aeronautical collection now displayed in World War II hangars.The new museum building is shaped like an isosceles right-angled triangle with a short side 161 m long and a clear height of 13.2 m from the floor to the underside of the roof framing. A two-storey wing on the west side contains the public entrances and the administrative offices.The soil at the site consists of a deep layer of preconsolidated sensitive clay underlain by dense glacial till containing boulders, then a layer of dense sand with gravel and boulders. The main columns of the building are supported by 55 m deep piles driven to suitable resistance in the dense sand and boulder layer, while the perimeter columns rest on spread footings, supported on the surface clay layer.The roof structure, which is one of the largest of its kind, consists of a space truss with top and bottom chords staggered with respect to each other and laid on a square grid 3.3 m by 3.3 m. The depth of the roof framing is also 3.3 m.The paper presents details of subsurface exploration and the types of foundations used. The structural framing for the roof as well as the steps involved in the analysis and design of the roof are described. Also presented are details of the fabrication methods, weld testing, and erection procedures. Key words: National Aviation Museum (Ottawa), pile foundations, dynamic testing, structural steel, space truss, welded joint, ultrasonic weld inspection.
Longitudinal cracking of composite beams with ribbed metal deck
Authors: Elkelish M. S. , Robinson Hugh
Published: January 2010

An analytical study of the longitudinal cracking of composite beams with ribbed concrete slab on metal deck is presented. A layered finite element is used to model the composite beam in the analysis. The influence of six parameters on the development of the longitudinal crack is investigated in this study. These parameters are type of loading, compressive strength of the concrete slab, beam span to slab width ratio, thickness of the solid part of the slab, percentage of transverse reinforcement, and the existence of the metal deck. Three types of loading are considered, namely, uniformly distributed load over the entire slab area, single point load applied at mid-span of the beam, and two point loads applied at the third points of the span. The type of loading of composite beams has a significant effect on the location of the initial longitudinal crack.
Disposal of acid-bearing and acid-generating sludges in the fertilizer manufacturing industry
Authors: Smith Adrian
Published: January 2010

Major waste products from fertilizer manufacture are calcine and so-called phosphogypsum, calcium sulphate. The oxidation and leaching of calcine produces a liquid with a high acidity and hence is acid generating. Disposal of phosphogypsum, an acid-bearing waste, is normally effected by construction of a tailings impoundment, similar in nature to those utilized for tailings disposal in the mining industry.This paper addresses the general chemistry, pollution potential, and chemical attack potential of both calcine and phosphogypsum and the impact these have on their disposal. The similarities and differences in the design philosophy for acid-bearing and acid-generating waste facilities are then discussed. Key words: phosphogypsum, acid sludge, fertilizer manufacture, water pollution, waste disposal, calcine, sulphuric acid manufacture.
Model test of a pumping station wet well
Authors: Alexander Lamoire J. D. , Aldworth George A.
Published: January 2010

A case study is presented describing the sump model test of a wet well in an existing sewage pumping station at the Regional Municipality of Ottawa–Carleton Green Creek Pollution Control Centre in Ottawa, Ontario. The purpose of the test was to determine whether the existing sump could accommodate projected flow increases of up to 83% associated with the proposed expansion of the plant. It was anticipated that the (low increases could cause the formation of localized flow disturbances such as vortices and eddies, which might induce unacceptable cavitation and (or) vibrations in the proposed new larger pumps. The sump model was constructed entirely of Plexiglas to facilitate flow visualization enhanced by a dye tracer. Of particular interest was the use of a laser Doppler anemometer to measure velocity distributions at critical locations such as the pump intakes. This provided a significant improvement in accuracy and convenience over more conventional velocity-recording devices such as a pitot tube or hot-wire anemometer. The methodology and considerations in the selection of the model scale are described. Key words: model, sump, similitude, vortices, pumps.
Durability design criteria for bituminous pavements on orthotropic steel bridge decks
Authors: Bild Stefan
Published: January 2010

Many inspections of the pavements of orthotropic steel bridge decks show longitudinal cracks above the connections of the deck plate to the main girders and ribs. By using a simplified model for analysing the behaviour of the pavement and comparing the theoretical results with damage records, the ultimate resistance of the pavement is defined, and minimum stiffness requirements for orthotropic decks are derived. These serviceability limit states have been included in a recent draft of the German steel road–bridge code DIN 18809.Theoretical studies of the material behaviour lead to proposals for the minimum strength requirements for bituminous pavements, which may be used in conjunction with the results of material tests. This procedure will improve the strength design of bituminous bridge pavements. Key words: bitumen, bridge decks, composite structures, design criteria, durability, limit design method, orthotropic plates, pavements, serviceability limits, specifications, steel.
Rotational restraint of a simple column base connection
Authors: Picard A. , Beaulieu D. , Pérusse B.
Published: January 2010

This paper presents the results of an experimental investigation on the behaviour of steel column base connections. The purpose of the study was to determine the value of the rigidity ratio at the column base (GL). The connection is made of a steel base plate welded to the lower end of the column and attached to the footing by means of two or four anchor bolts. It is generally admitted that this type of connection behaves like a hinge and it is recommended to use GL = 10.0 to evaluate the effective length factor of the column.The test results indicate that for weak-axis buckling a conservative value of the rigidity ratio is GLY = 0.50 and for strong-axis buckling GLX = 1.50, if there is no relative displacement of column ends. The effective length of the column is therefore reduced. A design example shows that the column strength is increased by approximately 30% for slenderness ratios currently met in practice. Key words: steel column, column base connection, moment–rotation curve, buckling.
Development of loading-truck model and live-load factor for the Canadian Standards Association CSA-S6 code
Authors: Agarwal Akhilesh C. , Cheung Moe S.
Published: January 2010

Studies have shown that the MS-200 loading model in the Canadian Standards Association standard CAN3-S6-M78 for design of highway bridges no longer represents modern-day heavy trucks in Canada. For the new edition of the CSA-S6 code, based on the limit states philosophy, a new loading-truck model was developed based on the Council of Ministers' loading, which is the legal load limit for interprovincial transportation in Canada. The loading model, designated as the "CS-W loading truck," provides the flexibility to adopt a multiple-level loading system appropriate to various jurisdictions.The live-load factor was determined from a statistical approach using data from a truck survey conducted across Canada in seven provinces. Responses in simple-span bridges were determined by running one or more trucks from the survey across the bridge. Based on this study, a live-load factor of 1.60 was determined and CS-600, with a gross weight of 600 kN, was selected as the standard load level. As well, the validity of the truck model and the live-load factors were checked for continuous-span bridges. Key words: highway bridges, design loads, codes and standards, live-load models, load factors, load surveys, vehicle weight regulations.
Beam-to-column connections in steel frames
Authors: Morris Glenn A. , Packer Jeffrey A.
Published: January 2010

The importance of beam-to-column connections in determining the load–deformation behaviour of steel building frames has been recognized for more than 70 years. Yet steel design specifications, including Canadian Standard Association standard CAN3-S16.1-M84, still mandate that connections be treated as either "pinned" or "rigid," and prescribe approximate design assumptions accordingly. Structural analysis procedures and tools exist that can account adequately for connection behaviour. What is not complete is the knowledge of the force–deformation behaviour of the various connection types.In this paper, what is known of the force–deformation behaviour of the commonly used connection types is described. The factors influencing that behaviour are outlined. Procedures for modelling connection behaviour and for incorporating it into structural analysis computer programs are described. The effects of connections on the behaviour of the overall structure are described and illustrated with examples. Finally, the areas where additional research is needed are discussed. Key words: connections, steel, structural analysis, columns, semirigid design.
A stochastic real-time spring flood forecasting system for Carman, Manitoba
Authors: Fay D. M. , Watt W. E. , Watts D. G.
Published: January 2010

A stochastic system for short-term spring flood forecasting for the Boyne River near Carman, Manitoba, has been developed. The system comprises two models. The upstream model consists of a transfer function noise algorithm which forecasts 6-h mean streamflow up to 36 h ahead for a site near Stephenfield, upstream of Carman. The inputs to this model are the recorded discharge of the Boyne near Stephenfield, temperature and precipitation during the melt period, cumulative winter precipitation, and an antecedent precipitation index for the previous summer and fall seasons. The downstream model is a transfer function noise model which uses previous discharges near Carman and recorded and forecast discharges near Stephenfield to forecast streamflow near Carman. Water-level forecasts near Carman are estimated from the forecast discharges with a stage–discharge relation for the site. Separate data sets were used to calibrate and verify the system. The system produced good forecasts for lead times up to 2 days. Key words: real time, floods, forecasting, snowmelt, simulation, transfer function noise modelling, antecedent precipitation index.
INTASK—a program for postelastic dynamic analysis of three-dimensional structures
Authors: Lai Shing-Sham , Will George T.
Published: January 2010

An inelastic analysis program for three-dimensional structures subjected to static/gravity loads and (or) dynamic loads in the form of three translational and orthogonal components of base motions is described. Using incremental integration technique, the program computes structural response as a function of time. Deformation history of elements within the structure can be traced and pertinent information obtained via user element subroutines. Each node can possess up to six displacement degrees of freedom and can accommodate user elements with any specified nodes and degrees of freedom per node. The program is very flexible for modelling different structural configurations, and components like beam column elements, shear wall elements, slab elements, semirigid connection elements, and inelastic spring elements can be easily added to the base program. Key words: inelastic analysis, three-dimensional structures, earthquake, computer program, dynamic, stiffness matrix, base accelerations, unbalanced forces, element subroutines.
Mathematical models for bridge reliability
Authors: Tharmabala T. , Nowak Andrzej S.
Published: January 2010

System reliability of bridge structures is investigated. Three terms are used to describe the standard reliability: structure function, reliability network, and reliability function. A bridge structure is represented by a reliability network which makes it possible to formulate the reliability function of the system. The reliability function is used to evaluate the reliability of the system. Reliability network and the reliability function are formulated for various types of bridges. Effects of component failures on system reliability are illustrated with examples. Key words: bridges, mathematical models, redundancy, system reliability.
A methodology for optimal design of pipe distribution networks
Authors: El-Bahrawy Aly N. , Smith Alan A.
Published: January 2010

A series of computer programs has been developed to assist in the optimal design of pipe distribution networks. These programs are capable of handling nonstandard network components such as booster pumps, minor-loss devices, reservoirs, check valves, and pressure-reducing valves. All three stages of network problem, namely analysis, design, and optimization, can be solved using the same solution procedure. A known technique for layout design has been adapted to help in the selection of redundant links.The problem is formulated as a nonlinear program using as design variables the diameter, discharge, and shutoff head (where appropriate) for each link. Pump lift is assumed to be described by a parabolic Q–hp curve, the coefficients of which may be defined by the user. A powerful, large-scale, nonlinear, sparse-oriented package (MINOS) is used to solve the problem. The continuous solution obtained by MINOS is modified by a discretization procedure to arrive at the optimal discrete solution. The constraint matrix including the loop, nodal head, and continuity constraints is automatically generated.The user is required to supply a simple and concise data file that will be interfaced by a preprocessor to generate the large and complicated data file required by MINOS. The latter data file includes the nonzero elements of the constraint matrix, ordered and stored in a column-by-column fashion. A postprocessor is also used to convert the mathematical output of the package into easily understood engineering data. Three different network examples are used to demonstrate the different aspects of the model (i.e. nonstandard components, discretization procedure, and layout design). Key words: networks, optimization, design, distribution, water supply, nonlinear.
Recursive water quality forecasting models for urban catchments
Authors: Patry Gilles G.
Published: January 2010

Urban water quality forecast models for use in real-time integrated control of combined sewer systems are developed and applied to a small combined sewer system in Hamilton, Ontario. Water quality forecasts for lead times ranging from 5 to 60 min are provided for both suspended solids and chemical oxygen demand. Two modelling approaches are examined: (a) a statistical approach based on the formulation of autoregressive moving-average models with exogenous inputs and (b) a two-stage deterministic/stochastic model based on the first-order surface pollutant washoff model. While both groups of model yield comparable forecasts in terms of the mean absolute percent error in water quality forecasts, statistically based models were found to provide definite operational advantages. Key words: adaptative modelling, real-time forecasting, statistical model, stochastic system, urban hydrology, water quality modelling.
Use of peat in water pollution control: a review
Authors: Viraraghavan T. , Ayyaswami A.
Published: January 2010

Peat, besides being plentiful and inexpensive, possesses several other qualities that make it an effective medium for the removal of pollutants. This paper presents a review of its use in water pollution control — in the treatment of sanitary and industrial wastewaters. Key words: peat, water pollution control, wastewater treatment, onsite wastewater systems, industrial wastes.
Ozone disinfection of secondary effluent containing antibiotic-resistant Escherichia coli
Authors: Finch G. R. , Smith D. W.
Published: January 2010

A paired experiment using seven batches of activated sludge final effluent was used to determine the effect of ozone on the multiple-antibiotic-resistant (MAR) population of Escherichia coli. The experiments were conducted using a batch stirred tank reactor. No statistically significant difference was found in the proportions of MAR E. coli in the ozonated secondary effluent when compared with the nonozonated effluent. This was true for all levels of multiple resistance including simultaneous resistance to greater than or equal to five antibiotics. This suggests that using ozone for water and wastewater disinfection will not select for antibiotic-resistant bacteria as has been reported by other investigators for chlorine and ultraviolet radiation. Key words: antibiotic resistance, Escherichia coli, wastewater, ozone, disinfection, activated sludge effluent.
The Saddledome: the Olympic ice stadium in Calgary
Authors: Bobrowski Jan
Published: January 2010

The design and construction of Calgary's Olympic Saddledome is outlined from the conceptual stages to completion of the works. The choice of structure is justified in comparison with other possible solutions, taking into account the "wholeness" of the problem in preference to isolated parts.The preeminence of the organic solution to fulfil the complex function of the building, although clear by philosophical deduction, was tested by comparison with well-established systems in structural steel and inflated plastic.By consciously avoiding the easy task of simply copying traditional solutions, with improvements, and thereby imposing on the structure a prejudged, possibly unsympathetic character, the design evolved harmoniously and with a great source of satisfaction to those concerned with it. Key words: prestressed concrete, structural design, wind analysis, cable-supported roof, vibration analysis, construction.
Staggered shear design of concrete beams: large-scale tests
Authors: Cerruti Lou M. , Marti Peter
Published: January 2010

Two large-scale reinforced concrete I-beams were tested to failure. The principal difference between the two specimens was the angle of inclination selected for the diagonal compression field in the web. A 45° inclination was used for specimen CM1 whereas a 31° inclination was used for specimen CM2. The validity of the truss model approach used in design was confirmed by the observed behaviour of the specimens.Diagonal crushing limits given in the Canadian code CAN3-A23.3-M84 were found to be conservative. It is recommended to use these limits for uniformly stressed web regions when applying the staggering concept of shear design. For nonuniformly stressed regions it is proposed to investigate potential failure mechanisms assuming an effective compressive strength of the web concrete of [Formula: see text].Canadian code rules for determining longitudinal bar cutoff locations may be unconservative. To prevent the formation of premature collapse crack mechanisms, it is recommended to extend the bars beyond the theoretical cutoff points by at least one-half of the stirrup spacing. Key words: beams, concrete, deflection, deformation, design, failure, girders, limit design method, reinforcement, shear strength, shear tests, strains, stresses, tests.
Testing of zero-slump piling concrete
Authors: Rodway L. E.
Published: January 2010

For several years it had been noted in the field that in the absence of an accepted, rational standard method for testing impact-placed zero-slump piling concrete, a variety of strength levels were produced from the same sample of fresh concrete depending upon which of a variety of test methods happened to be used. Finally, in 1977 the Canadian Standards Association published a standard method. This method subsequently proved ambiguous and impractical in practice to many field engineers.This paper presents the results of a laboratory and field study conducted during 1985 directed at the rational development of a practical test method to realistically predict the appropriate concrete strength, [Formula: see text], to be used in the calculation of the structural load-carrying capacity of this type of pile. Key words: zero slump, impact piles, energy input, vibration, compaction, concrete strength.
Cracking of composite prestressed concrete sections
Authors: Ghali Amin , Elbadry Mamdouh M.
Published: January 2010

Partially prestressed composite concrete sections are analyzed for the stress and strain changes due to a normal force N or a bending moment M or a combination of the two. One general approach is presented, which can be used for any of the three loading cases on composite or noncomposite sections. The applied forces N and M are assumed of such magnitude to produce cracking. The distribution of stress existing before the application of N and M must be determined a priori. Key words: analysis, composite section, cracking, loads (forces), precast concrete, prestressed concrete, stress, strain, tension stiffening.
Behaviour and evaluation of pin-connected steel truss bridges
Authors: Bakht Baidar , Jaeger Leslie G.
Published: January 2010

Two posted bridges, with pin-connected steel trusses, were recently proof tested in Ontario. This paper presents some results of the tests and draws conclusions, which are also applicable to other similar structures. It is concluded that, unlike other bridge types, this type of bridge does not possess reserve strengths beyond those ascertained analytically. An experimental procedure is given in the paper using which the ratio of dead loads in the two components of a tension chord can be readily determined. This paper also describes a procedure by which equivalence between the test and design vehicles is established, thereby providing a basis for determination of the posting loads. Key words: bridge evaluation, bridge testing, pin-connected truss, posting load, proof test, through truss, steel truss, tension chord.
Guideway design and construction for Vancouver Advanced Light Rapid Transit
Authors: Mills Donald L.
Published: January 2010

The Vancouver Advanced Light Rapid Transit (ALRT) System consists of 21.4 km (13.3 miles) of grade-separated guideway between the cities of Vancouver and New Westminster. Of the total length, 16.6 km (10.3 miles) are elevated, 1.3 km (0.8 miles) are in tunnel, and 3.5 km (2.2 miles) are at grade. There are 15 stations and a maintenance and vehicle storage facility. The system uses linear induction motor driven, light-weight driverless cars which are automatically controlled from the operations center located in the maintenance facility.The guideway beam concept was developed in concrete with the requirement that direct track fixation be used without a second pour. The beams are post-tensioned, following erection into two- and three-span continuous structures, encastre at the internal supports, with single pot bearings at the expansion ends.During construction the management for the project was provided by a joint project organization (JPO) consisting of the system contractor, Metro Canada Ltd., and the owner, B.C. Transit. The JPO was formed part way through the project to reduce duplication of effort and improve communication and coordination.Quality assurance for all materials and construction was critical to the successful completion and operation of the system. To ensure quality, the JPO instituted a detailed quality assurance (QA) and quality control (QC) program, implemented through the construction management team.Production of the precast guideway beams for the project was undertaken by two separate contractors. The initial contractor produced the beams for the 1 km prebuilt or demonstration phase, requiring 74 beams. The second contractor produced the remaining and major portion of the elevated guideway beams, for phase 2, amounting to an additional 1040 beams. Information obtained from phase 1, the prebuilt section, was used to modify the structural design, equipment requirements, and production and construction methods for phase 2.The cost of the transit system including 114 vehicles and all operation and control equipment was budgeted for a maximum expenditure of $854 million of which approximately $240 million was for civil works for the guideway, stations, and maintenance yard.Construction of the guideway began in August 1983 and was completed in December 1985. The guideway began operation January 1, 1986 on time and on budget. Key words: transit, automated, design, construction, guideway precast, concrete, quality assurance.
Le barrage Sartigan dans la Beauce (Québec), Canada : un cas-type de détérioration du béton par des réactions alcalis–granulats
Authors: Bérubé Marc-André , Fournier Benoit
Published: January 2010

The Sartigan dam, a concrete ice-retention dam built in 1967 along the Chaudière River, near Saint-Georges de Beauce, Quebec, Canada, shows numerous megascopic and microscopic signs of alkali–aggregate reactivity of the alkali–silica type (expansion, polygonal map cracking, silico-alkaline gels, looseness of cement paste – aggregate bonds, characteristic rims on fracture surfaces through coarse reactive aggregate particles, etc.). Besides, the three conditions considered as essential to promote these reactions in concrete have been satisfied in this case: the use of a high-alkali cement, conditions of high humidity reinforced by frequent wetting–drying cycles, and aggregates considered as potentially alkali-reactive in concrete (rhyolitic tuffs with a devitrified matrix rich in microcrystalline quartz).
Construction of the Broadway Bridge at Saskatoon, Saskatchewan, in 1932
Authors: Ostrander J. R. , Oliver D. C.
Published: January 2010

Saskatoon in the late twenties experienced a minor construction boom. Then in 1930 the Depression hit, coinciding with more than a decade of drought that decimated Saskatchewan's farm communities and urban centres. In 1931 Saskatoon proposed a relief project. It would construct a concrete arch bridge across the South Saskatchewan River connecting the downtown business district with Nutana.Acting as the City's consulting engineer, C. J. Mackenzie, Dean of Engineering at the University of Saskatchewan, directed the design of the bridge. The metastable south bank, much higher than the downtown side of the river, was a major factor in his design. The simple geometric lines of the structure resulted in its enduring aesthetic quality.As a relief project, the Broadway Bridge had to be constructed within a year. All labour was obtained from the ranks of unemployed married men. Often 450 men were employed at once, working three shifts around the clock. During construction of the piers, temperatures fell to −40 °C (−40°F) for several days. The river's flood stage in June made it impossible to construct the majority of the falsework in the river until July. By October, freezing temperatures were again being experienced.Yet for all the difficulties, on November 11, 1932, the bridge was officially opened. It had taken the people of Saskatoon less than 11 months to construct their bridge. Unfortunately, many years of even harder times loomed ahead. Key words: arch, bridge, concrete, construction, history.
Force reduction factors for the seismic provisions of the National Building Code of Canada
Authors: Rainer J. H.
Published: January 2010

A derivation of force reduction factors for the seismic provisions of the National Building Code of Canada (NBCC), 1985, is presented. This includes the following: classification of seismic actions, applicable limit states, change in load factor, derivation of force reduction factors, and classification of structural configurations. Quantitative comparisons are made between the derived force reduction factors and the response modification factors of the Applied Technology Council and good agreement was found. It is suggested that seismic requirements should be considered as accidental actions with a load factor αQ = 1.0. These results can form the basis for possible modifications to the 1985 NBCC seismic provisions. Key words: earthquake resistant structures, building code, loads, load factors.
Rectangular hybrid elements for the analysis of sandwich plate structures
Authors: Fazio P. , Gowri K. , Ha K. H.
Published: January 2010

The structural behaviour of sandwich plate structures are characterized by transverse shear deformations in the core. The assumed stress hybrid finite element technique is particularly suitable for developing sandwich plate bending elements. In the present study, rectangular three-layer sandwich plate elements have been formulated using simple assumed stress functions. Numerical test problems have been solved to examine the convergence property and suitability of these elements. The results are compared with that of a complete quadratic stress mode element and with analytical solutions. Six degrees of freedom per node shell elements are formulated by combining the plate bending elements with membrane elements. A folded plate sandwich panel roof has been analyzed using these elements and the results are compared with the experimental values. The use of simple stress function gives satisfactory results and reduces the size of the matrices to be used, the length of the program, and the computation time for the formulation of element stiffness matrices. Key words: sandwich panel, structural analysis, finite element method, stress hybrid approach, folded plates.
Columns in partially restrained construction: analytical studies
Authors: Nethercot David A. , Kirby Patrick A. , Rifai Abdussalam M.
Published: January 2010

The American Institute of Steel Construction Proposed Load and Resistance Factor Design Specification recognizes the ability of connections that function as less than fully rigid to transmit limited moments and to provide some measure of end restraint to columns in its definition of partially restrained (PR) construction. An analytical procedure for determining the response up to collapse of subassemblages in which semirigid beam-to-column connections are present is derived. This employs a nonlinear finite element column analysis together with analytical representation of experimentally determined connection moment–rotation [Formula: see text] curves. To trace the full response under any load path produced by a combination of beam loads and direct column load, it is necessary to allow for possible reversal in the direction of rotation of any of the connections. The program is used to study the effect of different connection types (ranging from very flexible web cleats to almost rigid extended end plates) and different load paths on column behaviour in nonsway subassemblages. It is found that the degree of rotation required from each connection is an important parameter in determining column response. Key words: buckling, columns, connections, frames, stability, steel, structural design, structures.
Behaviour and transport of oil under smooth ice
Authors: Puskas James , McBean Edward , Kouwen Nicholas
Published: January 2010

Mathematical and physical models are used in studying transport of oil slicks beneath ice in the presence of an ambient water current. The mathematical expressions for the relevant forces are developed by utililizing basic boundary layer theory and considering the physical properties of the oils and are verified from the laboratory experiments. Three different crude oils are utilized beneath freshwater ice under various flow conditions in the experiments.The transport of oil slicks oriented longitudinally to the direction of the water flow are modelled by the summation of the shear force at the oil – water interface and the oil – ice friction force. Oil slicks oriented transverse to the direction of the water flow are subjected to an additional form-drag force acting as the primary driving force.For oils with low viscosities, the oil – ice friction force can be approximated by assuming "no-slip" at the oil – ice interface. Oils with high viscosities move almost as a solid mass, with the majority of the velocity variation taking place in a thin water film separating the oil and the ice. Key words: boundary layer theory, environmental engineering, ice, mathematical models, oil spills, physical models.
Interconnection of boxed angle compression members
Authors: Temple Murray C. , McCloskey David C. , Calabrese Joseph M.
Published: January 2010

Recent research on the interconnection of starred angle compression members has indicated that the requirements for the interconnection of such members as contained in North American standards are not adequate. It was also determined that the North American and European standards vary greatly in their requirements for the interconnection of double angles. As a result, concern was expressed with regard to the requirements for the interconnection of boxed angles.A total of 27 boxed angle compression members were tested. The slenderness ratio, size of angles, and number of interconnectors were varied. The failure load and failure mode were noted for each specimen.This paper recommends that two interconnectors be used, one at each of the third points, in all boxed angle compression members. Key words: angles, buckling, building (codes), columns (structural), design interconnection, boxed angle.
A study of fly ash concrete in curb and gutter construction under various laboratory and field curing regimes
Authors: Gifford P. M. , Langan B. W. , Day R. L. , Joshi R. C. , Ward M. A.
Published: January 2010

It has been assumed that cement – fly ash systems only work efficiently given full curing; low temperatures and (or) moisture loss may lead to poor (slow) strenght development and concomitant reduced freezing and thawing cycling and scaling performance.The aim of the present study, undertaken by the Calgary Fly Ash Research Group, was to examine the validity of the above assumption. Strength development and freezing and thawing durability characteristics of fly ash concretes subjected to a range of environmental variables are reported; laboratory and field tests were performed. The field study involved a coring and laboratory testing programme on three ready-mixed concretes, which were used to machine place 200 m of standard curb and gutter on a major roadway. In the laboratory programme the field concretes and an additional high fly ash mixture were cast; specimens were demoulded at the age of 4 h and were either sealed at the time of casting or allowed to dry out while curing at room temperature or at 5 °C. Strength development, freezing and thawing effects, and scaling resistance as well as air-void parameters were determined; a comparison between the field and laboratory tests is presented. Also reported are measurements of internal concrete temperature and moisture loss versus time for the different curing regimes of the laboratory specimens. Key words: concrete, fly ash, strength, durability, field trial.