bluuebunny/crossref_metadata_2025 huggingface dataset:
A multinomial logit approach for multimodal choice of work trips
Authors: Cherian Varghese , Sargious Michel A.
Published: January 2010

This paper reports the results of an explorative study on the possibility of using a multinomial logit model to replicate and predict multimodal choice for work trips in a Canadian urban context. Modal choice data from Toronto, where a multimode choice situation exists in the line-haul portion of the work trip, are used to develop the model.Both socioeconomic and system variables are used in developing the model and the parameters are estimated using maximum likelihood technique. The developed model is evaluated in terms of statistical criteria and reasonableness tests. It is further examined for its predictive ability by making choice predictions of the sample used in developing the model in addition to comparing the results with the published ones in this area. The overall modeling strategy to be used while developing and testing multimodal choice models has also been illustrated.The study shows that disaggregate models can provide reasonable results when used in forecasting the modal choice between various modes.
The Conestogo River Bridge—design and testing
Authors: Dorton R. A. , Holowka M. , King J. P. C.
Published: January 2010

The bridge is a three-span continuous steel plate girder structure with a concrete deck slab that is longitudinally prestressed for full composite action. It was selected as a development bridge to incorporate a number of recent research findings and new design techniques.The design live loading was modelled on the observed truck loadings in Ontario, and a grid analysis and a new load factor method were employed for design. The usual specification deflection and impact values were abandoned in favour of a dynamic analysis, resulting in the selection of a very flexible structure with a low natural frequency. Other features include the use of high strength bolts as shear connectors and of slab test panels designed for membrane action with greatly reduced reinforcing steel.The paper describes the initial research, the design features and procedures, the instrumentation of the bridge, and the test programme using two load test vehicles each of which could be loaded to 200 kips (90.72 t). The testing and results are reviewed, and the significant findings are related to the design assumptions and the earlier research. Initial evaluation of the test data indicates that the dynamic testing results and the slab testing results in particular promise to have considerable effect on future designs.
Distribution of wheel loads on bridge girders
Authors: Culham Gerald A. , Ghali Amin
Published: January 2010

This paper is concerned with the analysis of simply supported concrete bridges composed of main girders, having cross sections in the form of a T or an I, interconnected by cross girders. A simple empirical formula is presented for the distribution of wheel loads between the main girders. The formula is based on the computer analysis of a wide range of bridges idealized as a grid. The empirical formula and the computer results show good correlation.The formula presented is intended for use in bridge design and is suggested to replace equations in current American and Canadian specifications for highway bridges (AASHTO 1973 and CSA S6-1974), which lead in most cases to overly conservative designs.
Computer programs for structural analysis and design — a Canadian view
Authors: Firmin A. , Gilmor M. I. , Collins R. A.
Published: January 2010

In recent years there has been a rapid expansion in the number of structural analysis and design computer programs commercially available to the design engineer. The following paper summarizes the current 'state of the art' of this software and outlines some of the major features. A broad coverage of the practical considerations surrounding the use of these programs is followed by a description of individual programs and their uses. Only those programs known to be readily available through Canadian computer bureaus are included in the review.
Rigid framing connections for tubular columns
Authors: Giroux Y.-M. , Picard A.
Published: January 2010

This paper presents the design and development of rigid framing connections between wide flange beams and tubular columns for the case where the beam flange is substantially narrower than the column face. The present report is a sequel to a previous paper dealing with a connection in which the beam flange and the column face are of equal width.In the connection proposed here the transfer of flange stress from the beam to the sides of the column is effected by means of coped strap angles while transfer of shear to the column face is done through welded double angles.The experimental program comprised 15 specimens, including 2 standard rigid joints introduced to give a comparison basis for the [Formula: see text] (moment–rotation) curves.The results indicate that, in the case of a beam flange narrower than the column face, both special attention to the geometrical design of the strap angles and provision of a web connection (not required in the first case) are necessary to ensure that brittle fracture will not take place in the strap angles. A connection is then obtained which can develop the plastic moment MP and sustain appreciable inelastic deformation and is therefore suitable for plastically-designed frames.The rigidity of the connection, slightly less than that of a standard joint to a wide flange column, makes it a 'nearly rigid' connection.Exploratory analysis of the effect of that relative loss of rigidity on the sway behaviour of multi-story frames shows that, while this influence should not be critical for frames of the height that would normally be possible with the currently-available hollow structural sections, it may be significant enough to warrant investigation of P-Δ effects.A design procedure is proposed in the Appendix.
Laboratory formation of border ice and frazil slush
Authors: Hanley T. O'D. , Michel B.
Published: January 2010

Ice formation under controlled conditions was studied in a cold room using a cylindrical steel tank 120 cm in diameter and 76 cm deep. Paddles turned by a variable speed motor moved the water about the axis of the tank. Twenty-one thermistors were used to record temperatures above and below the surface of the water. Ice was allowed to form with the cold room temperature held at −2 °C, −5 °C, −10 °C, and −20 °C and with water speeds (measured 4 cm from the tank wall) from 0 to 73 cm/s.At zero water speed ice formed first as needles randomly oriented over the surface. With flowing water, border ice width increased linearly with time, but independently of water speed. The rate of increase of the border width w fits the equation dw/dt = (4/9)|Ta|0.68 where Ta is the Celsius air temperature.Frazil was never observed at water speeds less than 24 cm/s, but was always formed at this or greater speeds, regardless of cold room temperature. The volume of slush accumulated was greater at greater water speeds and at colder air temperatures. Observed slush volumes are compared with semiempirical values of the ice mass obtained from theoretical equations. The data suggest that growth of ice crystals began when the water was supercooled by approximately 0.02 °C.
A method for assessing the fire resistance of laminated timber beams and columns
Authors: Lie T.T.
Published: January 2010

A method for the calculation of the fire resistance of timber beams and columns is described. The method is based partly on the results of theoretical studies and partly on the results of a large number of tests on timber beams and columns. Simple formulas for calculating fire resistance are presented. Comparison with experimental results shows good agreement between calculated and measured fire resistances.
Tests on hollow structural section beam columns
Authors: Pillai S. Unnikrishna , Kurian V. J.
Published: January 2010

Modified interaction equations have already been proposed for the ultimate strength design of square hollow structural section columns subject to biaxial bending. The Canadian Standard S16.1-1974 permits the use of these equations for class 1 and class 2 square hollow structural section beam columns. Results of a test programme undertaken to verify experimentally the validity of these equations are presented in this paper. Tests were conducted under various combinations of axial compression and biaxial bending moment. From the test results it is concluded that the proposed interaction equations give a safe and satisfactory strength criterion for the limit states design of class 1 and class 2 square hollow structural section beam columns.
Unique diversion tunnel closure
Authors: Spurmanis A.
Published: January 2010

This paper describes a method of diversion tunnel closure that is fast and efficient. The word "unique" used in the title implies that at the time the design was made, no description of a similar method could be found in the technical literature.
Use of zero-tension lysimeters in septic tile investigation
Authors: Viraraghavan T. , Warnock R. G.
Published: January 2010

The installation and the use of zero-tension lysimeters to obtain percolates from an experimental septic tile bed are described. These lysimeters are inexpensive and easy to install. They have considerable potential for use in many investigations where the systems are constructed in shallow depths above the water table. A summary of the results of the study is also presented.
Charts for water hammer in pipelines with air chambers
Authors: Ruus Eugen
Published: January 2010

Upsurges and downsurges are calculated and plotted for a simple pump discharge line provided with an air chamber. Basic parameters such as pipeline constant, air chamber parameter, pipe wall friction, and orifice resistance are used. The results of this paper can be used to determine the necessary volume of the air chamber. Computer studies indicate that the assumption of the rigid water column and the concentration of pipe friction at the pump end of the pipeline yields reasonably good results at the pump end; however, because of these assumptions, large errors in estimation of both upsurges and downsurges occur at the midpoint and particularly at the quarter point of the pipeline. Pipe friction has a substantially different effect on surges than that of the orifice resistance; these two effects should therefore be considered separately. A differential orifice is recommended and considered; this orifice should have a low resistance to flow out of the chamber.
Selection of concrete bridge systems
Authors: Lampert Paul
Published: January 2010

The basic information needed for the selection of appropriate bridge systems of short and medium spans is given. The options in the longitudinal and transverse sense and in the choice of the supports are described. Then, by means of the Sasselli Viaduct (in project), the application to a selection problem is demonstrated.
Analysis of wood diaphragms and trusses. Part II: Truss-plate connections
Authors: Foschi Ricardo O.
Published: January 2010

An analysis of truss-plate connections is presented, taking into account the nonlinear character of the load–deformation relationship. The connection is considered as ‘continuous’ because of the high density of teeth, and connector properties are derived from those for a single tooth. Parameters considered in the analysis include the actual shape of the connected area, gaps between connected members, the buckling capacity of the plate, and its yielding in tension and shear. Good agreement is shown in a comparison between theoretical and experimental results using a single connection under eccentric loading.
A model study of St. Marys River ice navigation
Authors: Cowley J. E. , Hayden J. W. , Willis W. W.
Published: January 2010

Ice conditions on the St. Marys River hamper winter navigation between Lake Superior and Lake Huron. Vessel movements in the river during winter months lead to changes in the river ice regime and affect local ferry service across the river. A hydraulic scale model of a 7300-m length of the waterway extending downstream from the Soo Locks was used to compare alternatives for relieving these effects. Methods for representing ice behavior were a key element in the model study.An arrangement of ice booms with an open ship passage which does not impede navigation was developed and recommended on the basis of model tests. That boom arrangement was installed at the end of 1975 and proved to be highly effective under the ice conditions experienced in the 1975–1976 and 1976–1977 winter seasons.
The use of conversational computer programs in the structural engineering office
Authors: Wright Whitman
Published: January 2010

As a result of improved facilities, reduced computing costs, and the availability of better programs, conversational computer programs are becoming effective design aids in structural engineering offices. The author outlines his work in writing conversational computer programs, and the techniques he has developed to make them successful.Some of the topics given attention are: the relationship between the engineering and the computer science aspects of the work; a technique for free-format data input; the planning of the dialogue to take place between the program users and the computer; the provision of technical support for the program users; the selection of the correct computer and the correct terminal for conversational programs; procedures for error checking, error correction and input data editing; electronic data transmission from program to program; development of the programs in a time-sharing environment; the use of modular programming; and trade-offs between the costs of the software and the hardware to support conversational programs. A limited amount of attention is given to the role of computer graphics in support of conversational computer programs.
Aerobic sludge digestion at cold temperatures
Authors: Mavinic D. S. , Koers D. A.
Published: January 2010

Continuous flow, daily fill and draw, and batch aeration digesters were studied on a laboratory scale, to develop low temperature characteristics and design criteria for aerobic digestion of waste-activated sludge. These results were compared against full-scale data, from three independent sources. Raw sludge used in these studies was obtained from a municipal high-rate activated sludge plant. The digestion systems were operated at temperatures of 20, 10, and 5 °C, and at six different sludge ages. Measurements of all parameters studied were made under steady-state conditions.The results show that the effect of low temperature on aerobic digester performance is pronounced. The combined effect of temperature and sludge age is shown to be an important design parameter. Kinetic reaction rates and temperature coefficients were calculated on the basis of total volatile suspended solids. It was shown that batch and continuous feed system reaction rates are not interchangeable. The laboratory results further show that there is little difference between continuous flow and daily fill and draw digestion characteristics, except at 5 °C. Difficulties encountered in making a valid comparison between the laboratory and full-scale results are also discussed.
Steady-state dissolved oxygen model for the Rideau River
Authors: Adamowski K. , Middleton A. C.
Published: January 2010

A steady-state, one dimensional dissolved oxygen (DO) model was developed for summer conditions for the Rideau River near Ottawa, Ontario. Model parameters were estimated for July 1975 conditions, and model acceptance was based on June 1975 conditions. Results of the model indicated that the tributaries in this section had only a marginal effect on DO concentrations. The major factor affecting DO concentrations was the distributed source–sink processes, which include photosynthesis, respiration, and sediment oxygen demand. River channel reaeration and aeration at dams had a minimal effect on DO.
Diffused aeration systems from theory to design
Authors: Bewtra Jatinder K. , Mavinic Donald S.
Published: January 2010

Aeration has been used successfully in northern Canada and other cold regions for treating domestic and industrial waste waters by aerated lagoons, extended aeration package units and conventional activated sludge plants. Many of these installations used diffused aeration because this system has shown several advantages over mechanical surface aeration. The advantages of using diffused aeration in cold regions for oxygenation as well as for mixing are discussed in this paper.The parameters affecting the efficiency of oxygen transfer and the mixing of the tank contents are identified and the influence of varying these operating parameters on the performance of diffused aeration systems under cold climatic conditions is discussed. Equations showing the influence of temperature, airflow rates, submergence and tank geometry on the overall oxygen transfer coefficient are presented.A process of aeration, employing counter-current flow of air bubbles and waste water, is shown to result in increased contact time and therefore higher oxygenation efficiencies. A typical example for designing a diffused aeration system in cold regions has been worked out.
Recycled concrete—a new aggregate
Authors: Malhotra V. M.
Published: January 2010

Large urban centres in Canada and the United States are finding it increasingly difficult to locate and develop natural aggregate sources for use in concrete. The study reported herein was therefore undertaken to investigate the possibility of producing aggregates from discarded concrete control test cylinders, normally sent to waste dumps after testing.A series of 2.2-ft3 (0.062-m3) concrete mixes were made covering the low, medium and high strength levels. Two sets of mixes were made at each strength level, one set consisted of a control mix and a mix made using coarse aggregate prepared from recycled concrete and reference fine aggregate; the second set consisted of a control mix and a mix using fine aggregate prepared from recycled concrete and a reference coarse aggregate. Cylinder and prism specimens were cast from each mix to determine mechanical properties of concretes at various ages and to study the durability of concrete after exposure to freeze–thaw cycling.The analyses of the test results have shown that satisfactory concrete can be made with aggregates prepared from recycled concrete. At lower water–cement ratios, strengths of the two types of concrete are comparable.The durability of concrete made with aggregates prepared from recycled concrete is comparable to the durability of concrete made with reference aggregates.
Dynamic analysis of two dimensional simply supported orthotropic bridge decks
Authors: Kulkarni G. G. , Ng S. F.
Published: January 2010

Forced vibration analysis of two dimensional bridge deck structures involves complex mathematical procedures and therefore analysis is often based on beam idealization of equivalent plates. This simplification yields close agreement only for long span bridges where plate action is relatively insignificant. However, such a concept of beam idealization cannot be successfully utilized in the case of short span bridges where plate action is predominant and where the determination of the distribution of dynamic deflections and amplification factors at critical sections of such plates is of prime concern. The principal objective of the present investigation is the forced vibration analysis of longitudinally stiffened, simply supported orthotropic bridge decks utilizing a new concept of interconnected beam idealization. The theoretical analysis deals with determination of amplification factors and dynamic deflections along critical sections of the plate treated as a series of interconnected beams. The aspect ratios of the plates under investigation as series of interconnected beams are designed to cover a wide range of plate to beam transition. The theoretical analysis is supplemented by an extensive experimental programme.In conclusion, it is seen that this concept of interconnected beam idealization not only takes into account the plate action of the deck structure but also reduces greatly the complexity of mathematical formulation. A good comparison between the theoretical and the experimental results indicates that this concept can be used to advantage for analysis and, within certain limitations, for design purposes.
Treatment of a complex landfill leachate with peat
Authors: Cameron Robert D.
Published: January 2010

The use of cheap, locally available peat as a treatment method for landfill leachate was investigated by passing leachate through plexiglass columns filled with an amorphous-granular peat. Preliminary adjustment of pH showed that reducing pH to 4.8 dramatically reduced adsorption. Increasing the pH to 8.4, metal removal was increased owing to filtration of precipitated metals. The best adsorption of metals occurred at the 'natural' pH of 7.1. Manganese was found to be the limiting pollutant. At the 0.05 mg/ℓ maximum acceptable manganese concentration 94% of the total metals were removed, requiring 159 kg of peat per 1000 ℓ of leachate.Resting the peat for 1 month did significantly increase removal capacity.Desorption of some contaminants occurred when water was percolated through the peat. The desorption test effluent was not toxic to fish although iron, lead and COD (chemical oxygen demand) exceeded acceptable values.Chemical pretreatment using lime and ferric chloride achieved significant iron, manganese and calcium removals. Chemical pretreatment followed by peat adsorption offered no advantage other than reducing toxicity to fish.Peat treatment alone was effective in reducing concentrations to a level that was non-toxic to fish.
Ice and wave action on artificial islands in the Beaufort Sea
Authors: Croasdale K. R. , Marcellus R. W.
Published: January 2010

Artificial islands are being used in the Beaufort Sea to conduct exploratory drilling for hydrocarbons. By May 1977, 15 islands had been built in water depths ranging to the 5 fathom isobath (8.5 m). Ice up to about 7 ft (2 m) thick covers the Beaufort Sea for 9 months of the year and has a considerable influence on construction methods and island design. The islands need sufficient sliding stability to withstand the forces generated by the moving ice; and the possibility of ice ride-up has to be considered. Islands can be built either during the winter by trucking gravel over the ice or in the short arctic summer using dredges. Temporary slope protection is needed to avoid beach erosion during the short summer months. Slope protection is designed to match the measured and predicted sea state, which also influences the island freeboard needed to avoid wave overtopping. Slope protection methods include anchored polyfilter cloth, sandbags and sacrificial beaches. Optimum island designs have to account for constructional constraints, working area needed, ice action, wave action and geotechnical factors.
Automated design of rigid steel frames including member selection
Authors: Wright Peter M. , Hakim Hosny Fawzi
Published: January 2010

This paper outlines a new algorithm for the automated design of rigid plane steel frames having multiple loadings, displacement constraints, stress constraints and fixed geometry. The most significant contributions are, first, a method developed for incorporating into an optimization program the requirements of the specification CSA S16-1969 so that the program automatically uses realistic allowable stresses and, second, a procedure introduced for selecting actual sections that correspond to the theoretical solution. Elastic analysis is used and the optimum design is selected on the basis of minimum cost using the preliminary design factors recommended by the Canadian Institute of Steel Construction. Several examples, including a 10-storey, 1-bay frame, are included to demonstrate the capabilities of the algorithm.
Cold-formed steel in composite bridge construction
Authors: Kennedy John B. , Madugula Murty K. S. , Keen Robert G. , Fung C.
Published: January 2010

Laboratory tests were conducted on a full scale prototype of a segment of a bridge superstructure of cold-formed steel box girders in composite construction with a reinforced concrete slab. The results indicate that such a superstructure has adequate ultimate load carrying capacity, is effective in distributing concentrated loads laterally, and that the specially-formed shear connectors (lugs) are quite successful in shear transfer; furthermore, the design parameters can be predicted by means of ordinary analytical methods. Based on the field performance of a similar superstructure for a bridge over the Slate River and on the laboratory test results, refinements in the design that should lead to further economies for this type of construction are suggested.
Finite strip evaluation of effective flange width of bridge girders
Authors: Cheung M. S. , Chan M. Y.T.
Published: January 2010

Concrete and steel–concrete composite beam-slab type and box-girder bridges are analyzed using the finite strip method, a variation of the powerful finite element method. The results obtained are used to determine the effective width of the compressive flange of the bridge girders. A study of a wide range of bridge models resulted in an empirical relationship that is in good agreement with the design criteria set down in the composite road bridge design code of the Federal Republic of Germany.The empirical relationship presented in this paper is intended to supplant the effective width specifications in current American and Canadian design codes, which in general lead to conservative designs.
Initiation of ice jams — a laboratory study
Authors: Tatinclaux Jean-Claude , Lee Chu-Liang
Published: January 2010

Ice jam initiation by a simple partial surface obstruction in a channel was studied experimentally in laboratory flumes using polyethylene, paraffin, as well as real ice parallelepipeds, as model ice floes. The important dependent parameter under study was the critical surface concentration of floes at the gap in the surface obstruction at which floes would form a stable arch across the gap and an ice jam would be initiated. This critical floe concentration Cg* was found to be independent of the ratio of gap width to flume width and to be a decreasing power function of the ratio of floe size to gap width. In addition Cg* was found to be independent of the approach flow Froude number for flow velocity less than the critical submergence velocity of an ice floe, for artificial model floes, but to increase with increasing Froude number when real ice floes were used. This difference and other quantitatively different results depending on whether natural ice blocks or plastic blocks were used as model ice floes were tentatively attributed to differences in floe material characteristics, mainly interparticle friction force and surface tension property, the latter affecting significantly the critical submergence velocity of thin plastic blocks as compared to that of natural ice floes of the same size and density.
The aggregate shortage and high alkali cement in a changing energy situation
Authors: Grattan-Bellew P. E. , Sereda P. J. , Dolar-Mantuani L. M. M.
Published: January 2010

Shortages of good quality concrete aggregate may be experienced in the larger urban areas, across Canada, during the next 25 years. The potential shortfall in the supply of aggregate will be aggravated in many regions by legislation restricting the operation of pits and quarries. Potential supplies of aggregate will also be affected by the increasing cost of energy. The rising cost of fuel will result in higher haulage costs, which will make transport of aggregate from remote areas, where it is more plentiful, increasingly uneconomic. Some aggregates react with alkalis and are therefore unsuitable for use with high alkali cement. The increased cost of operating a cement kiln due to rising energy costs may be offset by increasing the alkali content of the raw mix, which then clinkers at a lower temperature and produces a cement with a higher alkali content. In some regions this might result in some aggregates, now acceptable, becoming unsatisfactory for use in concrete that is exposed to moist conditions. Potential shortages of good quality concrete aggregate point to the need to conserve supplies; one way of doing this would be to make concrete last longer by improved quality control of concrete exposed to harsh environments.
Simplified analysis of wall-frame structures
Authors: Moselhi O. , Fazio P. , Zielinski Z.
Published: January 2010

A simplified method is presented for the analysis of planar, uniformly perforated walls under the action of lateral loads. The method is based on replacing the perforated wall by an elastically equivalent orthotropic plate. The principle of minimum total complementary potential energy is then used to determine stresses and displacements in the equivalent plate. Internal forces in the actual structure are obtained by direct integration of these stresses. An example is worked out to illustrate the application of the method and its accuracy. Design curves are presented for the rapid determination of internal forces.
Load testing of prestressed concrete transmission pole and its concrete footing
Authors: Ghosh Ram S. , Senkiw George A.
Published: January 2010

Full-scale load tests on a centrifugally spun, prestressed concrete pole installed in a reinforced concrete footing indicate that this structure can be used for transmission lines if some dimensional changes are made to increase the torsional capacity of the pole to withstand broken-conductor loading conditions. The results also show that the strength and behaviour of the pole can be predicted analytically if the actual dimensions and properties of the materials are known. Strains in the reinforced concrete footing are very low and, in this case, indicate no need for reinforcing steel to resist stresses due to exterior loading. Where reinforcement is required for the control of cracks due to temperature and shrinkage, it need be included only in the upper part of the footing.
The strength of polycrystalline ice
Authors: Michel Bernard
Published: January 2010

The paper contains a general study on the strength of polycrystalline ice. A theory on the fracture of ice is proposed that starts from the observation of the mechanism of failure of monocrystalline ice and is based on the computation of the elastic stability of a grain of polycrystalline ice. It is verified with experimental data obtained from tests carried out at the Ice Mechanics Laboratory of Laval University. For brittle fracture it shows that when a crack is formed in one grain, it propagates immediately to the whole sample in a tensile test and is followed quickly by failure in a crushing test. An equation is derived that shows that the fracture strength depends on the crystal size and on the cohesive strength of the ice, which is only temperature dependent.The maximum strength of polycrystalline ice does not occur in the brittle range, but in the ductile range. Glen's law of creep of polycrystalline ice has been used to obtain, from the data, best fit curves between the yield strength and the strain rate, for each ice type. Strength diagrams are presented for the full range of loading, including both ductile and brittle behaviour. A discussion is made on the transition from one mode of failure to the other and on the failure criteria for complex states of loading.Recommended values for the fracture strength of natural ice are submitted that have a direct application to the design of engineering structures.
An approximate theory for the shear deflection of plywood panels
Authors: Booth L. G. , Malde K. R.
Published: January 2010

An approximate theory for the shear deflection of plywood panels is developed using the assumptions of the Engineer's bending theory. The effects of load distribution, support conditions, and span may be separated from the effects of the material and geometrical properties of the cross section. The section properties are combined in a shear shape factor (S), which in its most general form is applicable to any number of veneers with different elastic moduli.A comparison is made between the approximate theory and a more accurate theory proposed by Foschi. The approximate theory overestimates the shear deflection by an unacceptable amount when the span–depth ratio and shear moduli ratio are both small, but for practical design cases it overestimates by approximately 5% and is a satisfactory design method.It is shown that S depends on the ratios of the elastic moduli parallel and perpendicular to the span and on functions depending on the geometry. The values of S for six thicknesses of plywood currently used in Canada are tabulated and it is shown that for face grain parallel to span a simplified linear relationship between S and the shear moduli ratio can be used. Hence the shear deflection can be calculated by reference to tabulated values only.
The results of a survey on structural out-of-plumbs
Authors: Beaulieu Denis , Adams Peter F.
Published: January 2010

Statistical characteristics obtained from measurements of out-of-plumb columns and walls in three core-braced buildings and one large industrial building under construction are presented. The new data are presented together with a summary of results of measurements previously available in the published literature. Special techniques are introduced for measuring out-of-plumbs and for reducing the data for use in design.
Performance of lapped splices in reinforced concrete loaded beyond yielding of the steel
Authors: Rezansoff Telvin
Published: January 2010

Eighteen beams designed to fail in the lap splice after reaching yield of the reinforcing steel were tested under either a single load application or low cycle repeated loading. Splice lengths were varied from well below code requirements up to approximately those required by current codes and design methods. Performance was studied on the basis of the ductility exhibited prior to failure and the influence of load cycling and stress–strain characteristics of the reinforcing steel. No confinement (stirrups or a spiral) was provided to the splice.Comparison is made with common lap splice design methods. These assume that the beam will respond adequately and the splice will not fail prematurely if the splice length is made long enough to withstand a steel stress 25% above the normal yield strength of the reinforcing steel. The detrimental effects on ductility of higher than nominal yield stress and of strain hardening at relatively low strains for the grade 60 (nominal yield stress = 60 ksi (414 MPa)) deformed reinforcing steel used are noted. The possible weakness of using nominal yield strengths for the reinforcing steel with current design methods is emphasized.
Evaluation of transportation systems—a behavioural approach
Authors: Khalil D. , Sargious M. A.
Published: January 2010

This paper reports the results of a study on developing level of service indices for evaluating urban transportation systems. For this purpose the travel choices of individuals are analyzed considering the effect of the transportation system characteristics on the system's level of service as perceived by the user. A utility maximization approach is used to yield a utility function that contains a new behavioural measure of accessibility. This function is considered as a level of service index that reflects the marginal benefits to a system's user when he makes a trip by the system.The parameters of the level of service indices are determined by using a sample consisting of 2695 trips obtained from the 1976 work trip survey for the City of Calgary, Alberta, Canada. Level of service indices are developed for four modes: auto driver, auto passenger, conventional bus, and express bus.The implementation procedure of the indices for assessment and evaluation is shown by a case study for the City of Calgary.
Duration of load and probability of failure in wood. Part II. Constant, ramp, and cyclic loadings
Authors: Barrett J. D. , Foschi R. O.
Published: January 2010

A generalized model for damage accumulation is used to study the probability of failure of a wood member in bending for different load histories. The variability in time-to-fracture corresponding to a given load history is accounted for in the generalized model. Four types of loads are considered: (1) a constant load, (2) a ramp load, (3) a cyclic load of constant cycle amplitude, and (4) a cyclic load of random cycle amplitude. In each case, the probability of failure is studied as a function of the factor [Formula: see text] which, in the design equation, is applied to the 5th percentile of the short-term strength distribution to obtain the design stress. Snow loading is considered as an example of cyclic load with random cycle amplitude.
Fatigue cracking in bridges from out-of-plane displacements
Authors: Fisher John W.
Published: January 2010

The interaction of the various components of a bridge structure under normal vehicular loading has sometimes resulted in cracking in unexpected locations in relatively short periods of time. In girder type bridges this cracking has often occurred in the web at short gaps between attachments and the flanges. Although the problem has been more prevalent with welded members, cracking has also occurred in riveted members.This paper examines three cases of fatigue cracking from out-of-plane displacements: one case in which transportation and handling resulted in high cyclic stresses at the ends of transverse web stiffeners; a second case in which the end rotation of transverse floor beams framing into longitudinal girder webs resulted in cracking at the end of the connection plates welded to the girder web; and a third case in which riveted connection plates connecting cantilever brackets to floor beams were found to be susceptible to in-plane bending as a result of relative movement between the girder and the floor system.Field and laboratory studies were beneficial in assessing the mode of behavior and causes of fatigue cracking. The results of these studies were useful in developing ways to avoid such cracking in the future.
Churchill River Diversion, Burntwood River Waterway: studies to evaluate winter regime
Authors: Hopper H. R. , Simonsen C. P. S. , Poulier W. J. S.
Published: January 2010

The Churchill River Diversion, from the outlet control at Notigi Lake to the Nelson River at Split Lake, is routed along the Burntwood River. This river, which normally carries a winter flow of about 1000 ft3/s (28 m3/s), will be required to convey a design flow of 30 000 ft3/s (850 m3/s).During winter, tranquil reaches of the waterway will quickly develop an ice cover while the swifter reaches will remain open and generate large quantities of slush ice. This ice will accumulate under established ice covers in the form of hanging dams and will alter the regime of the river.This paper describes the methodology used to estimate the changing regime of the Burntwood River Waterway, during the course of winter. The waterway was considered as a series of reservoirs, each of which may develop an ice dam. A computer program was developed to route diversion flows through these reservoirs, taking into account the quantity of slush ice generated and deposited to form the hanging dams.The results of routing present a time-based range of possible stages and flows along the waterway, the sizes of the ice dams formed, and the volume of water detained in the lakes along the waterway.
The design of partially connected composite open-web joists
Authors: Robinson H. , Fahmy E. H.
Published: January 2010

A method for calculating the ultimate flexural capacity of a composite open-web joist with partial connection is proposed. If the compression in the top chord of the open-web joist due to partial connection exceeds the buckling capacity of the top chord then the buckling capacity governs the design.
An estimate of the economic returns for a fish hatchery
Authors: McBean E. , Haycock D. , Gorrie J.
Published: January 2010

The capital and operating costs of public facilities such as fish hatcheries can normally be assigned fairly easily; the benefits are, however, much more difficult to determine. Due to the availability of an extensive data base for a hatchery proposed for Lake Huron, an estimate of the benefits was obtainable and the benefit/cost ratio derived is in support of project construction.
Morphological effects of interbasin river diversions
Authors: Kellerhals Rolf , Church Michael , Davies L. B.
Published: January 2010

Data on the morphological effects of 11 Canadian interbasin river diversions are presented and some of the more fully documented cases are discussed and illustrated. A classification of diversion routes is suggested and procedures for evaluating the morphological effects in each classification are proposed.
A discussion on the application of the safety index concept to wood structures
Authors: Foschi Ricardo O.
Published: January 2010

The special characteristics of wood as an engineering material, in particular high variability in strength and load duration effects, are discussed from the point of view of limit states design formulations based on the safety index concept. It is concluded that wood structures require a treatment that differs from that used with less variable materials and that, because of load duration effects, the safety index and the usual load–resistance formulation in limit states design become dependent on the load history.
Rigidities of concrete waffle-type slab structures
Authors: Kennedy John B. , Bali S. K.
Published: January 2010

Analytical expressions for the orthotropic rigidities of concrete waffle-type slab structures are presented; the expressions are valid for both the precracking and postcracking stages and are therefore applicable to reinforced and prestressed concrete structures. Formulae for the rigidities of orthotropic slab structures of uniform thickness are also given. Flexural and twisting tests on several concrete waffle-slab elements were conducted; the experimental results verify and substantiate the proposed analytical expressions. The use of realistic estimates for the orthotropic rigidities will lead to economy as well as better design of concrete waffle-type slab structures.
A survey of snow loads on the roofs of arena-type buildings in Canada
Authors: Taylor D. A.
Published: January 2010

The paper presents data on snow loads on three shapes of arena-type structures in Canada: the cylindrical arch, and the gable and Hipel roofs. Since there has never been a regular annual survey of snow on arenas, the data were compiled from a 4 year pilot study of snow on Quonset-type buildings, from case histories, and from newspaper clippings.The data indicate that the maxima of the loads recommended for design in Commentary H on snow loads published in Supplement No. 4 to the National Building Code of Canada 1977 can be exceeded.Further, it appears from the data that three loading cases should be considered in the design of curved roofs: uniformly distributed, unbalanced, and symmetrical loads. It is apparent also that the unbalanced loads recommended for gable roofs may be too conservative.
Practical code calibration procedures
Authors: Nowak Andrzej S. , Lind Niels C.
Published: January 2010

The paper deals with a procedure that can be used by a design standards committee to determine safety indices for structures and calculate optimum performance factors for limit states design. Six load components are considered: dead, sustained live, transient live, snow, wind, and earthquake load effects. The procedure is based on an approximation of the probability distributions by normal distributions in the design point situated on the failure boundary. The objective in selection of performance factors is closeness to a target safety level expressed in terms of the target safety index. A computer program was developed to be used in calibration. The procedure is illustrated by examples.
Damage and cost simulation in pumped storm sewers
Authors: Imam E. H. , McCorquodale J A , Bewtra J K
Published: January 2010

A flow-damage model has been developed to predict the annual probable damage due to basement and street floodings in relatively flat urban areas where pumping is required. The damage cost is obtained by integrating damages due to high as well as low probability storms. Annual capital recovery costs are also computed. The flow simulation is based on the Road Research Laboratory model, the Muskingum method, and a relaxation procedure for computation of surcharge conditions.

The model can be used for design purposes or to evaluate existing systems. A suggested design procedure incorporating the flow-damage and installation cost models along with linear programming has been used to obtain an optimum design for a given pumped storm-sewer system. The optimal design is achieved when the combined cost of annual operating capital recovery, and annual probable damage is minimum. The design variables include the depths, slopes and diameters of the sewers. as well as sump area, rated pumping head, and discharge.
Innovative designs in structural systems for buildings
Authors: Ritchie J. Keith , Chien Eddie Y. L.
Published: January 2010

Numerous innovations in the use of structural steel alone or in combination with other structural components have been tried and proven in North America during the past two decades. In numerous other fields of endeavour, mass production allows refinement in both function and cost. However, the 'one-off' approach inherent in both architectural and structural design of buildings on this continent and the broad spectrum of projects (and clients) processed by any single consultant, in spite of any desired level of specialization, allow development of only the low end of the learning curve related to the use of a particular system.This paper sets out with two objectives: the first is to review some of the innovative structural framing systems for steel buildings, presenting the concepts and design details for review by others who only infrequently have opportunities to design a structure falling in one of these categories; the second is to review possible adaptations of these structural systems with the objective of achieving greater construction efficiency and (or) greater economy.Systems reviewed will include concrete-cored, gravity steel-framed structures with a number of alternative construction methods, staggered truss-framing systems, interstitially framed hospital structures with a review of economics and mechanical–structural interface aspects, the stub-girder framing system with Canadian alternatives, steel–concrete composite action of both vertical and horizontal structural members, efficient lateral load-resisting systems such as direct acting tension and compression bracing, including both exterior and interior applications, steel-plate shear walls as lateral load-resisting elements, and combinations of the above.Structural interface with other building components including wall components will receive considerable emphasis, but overall, ways and means of improving productivity in both design and construction will be the primary focal points and objectives of the paper.
Les régimes hydrologiques du Québec septentrional
Authors: Lapointe Denis
Published: January 2010

Since the early sixties, considerable effort has been made to collect information on the hydrological regimes of the rivers of northern Quebec. It is during that period that most of the gauging stations were put into operation and therefore, after 15 years of record, we have in hand enough data to get a better understanding of the different conditions prevailing on these rivers.This part of Quebec is characterized by flat ground and low precipitation and so we could expect a light runoff. On the other hand, the great number of lakes and marshes of the region contributes to the lamination of floods and the increase of the low flows.The hydrological study concerns mean flows, water balance, seasonal variations, low flows, and floods. To realize these studies, we have chosen more than 30 stations located in the regions of James Bay, Hudson Bay, and Ungava. The record period varies from 12 to 15 years (1960–1975).