摘要:

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

ISSN:0315-1468    

DOI:10.1139/l86-064

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The most frequently cited cause of truck accidents is “speed too fast for prevailing conditions.” To cite this cause, a speed estimate is necessary. This paper shows the factors that should be considered. The factors most useful in estimating a truck's braking capability include vehicle configuration, loading, location of the centre of mass, and axles with brakes. The exact value of some of the variables is difficult to obtain.The formulation proposed in this paper builds on a simple and effective procedure used by police agencies to estimate speed from skid marks. The formula given by R. Rivers' “Traffic accident investigator's handbook” is formalized and the elements in his correction factorNare derived. Basic equations for the braking of straight trucks and combinations are derived. The difficulty of implementing the equations in practice for all but the simplest situation is obvious from the complexity of the equations. A lumping of all the parameters into a simplified form is developed based on truck stopping distances obtained from published experimental data. All the trucks in the data had well-adjusted brakes. The final equation to estimate speed from a truck's skid marks accounts for the average ability of such vehicles to stop as well as the variance in stopping ability.Key words: truck braking, braking efficiency, stopping sight distance, skid marks.

ISSN:0315-1468    

DOI:10.1139/l86-065

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Six parallel upflow anaerobic sludge bed reactors were operated at chemical oxygen demand (COD) loads from 3 to 10 kg COD/(m3∙d). Four reactors (R1–R4) were fed sodium sulfate at loads of 1–3 kg S-SO4/(m3∙d). Reactors R1 and R2 were fed spent cheese whey with R1 being operated in an unstripped and R2 in a stripped mode. At COD loads below 5 kg/(m3∙d), the removal in R1 was 60–80% COD and generally trailed R2 by a margin of 0–15%. At higher COD loads and at higher SO4/COD ratios, the performance of R1 deteriorated significantly. A similar situation was found in the pair R3 (unstripped) and R4 (stripped), which was fed a mixture of spent whey and sulfite cooking liquor. Reactors R5 and R6 were subjected to the same feed as R3 and R4, but no sulfate was added. A comparison of R4 with R6 indicated slightly lower COD removal in R4 with similar amounts of volatile fatty acids accumulating in both reactors in cases of overloading.Key words: anaerobic treatment, sulfides, methanogenesis, inhibition, sludge bed reactor, dairy wastes, pulp and paper wastes, sulfate redu

ISSN:0315-1468    

DOI:10.1139/l86-066

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Amok Ltd. is the operator of uranium mining and milling facilities at Cluff Lake in northwestern Saskatchewan. All contaminated liquid effluents from these facilities have been subject to treatment by chemical and physical methods before release to the environment. In particular, a secondary treatment system (STS) has been operated adjacent to the tailings management area to reduce the concentration of radium-226 to below the maximum levels allowable in the final effluent. The STS has operated for over 2 years at a nominal rate of 4000 m3/day. During this time, the most stringent regulatory limit on radium-226 concentration (0.37 Bq/L = 10 ×10−12 g/L total, based on a monthly arithmetic mean) has been exceeded on only two occasions. The process regularly removes 99% of the radium from the effluent stream. Data is presented on chemical addition rates, efficiencies of system components, and the significance of each stage of the treatment process. In addition, several modifications have been made to the STS. Recently, a primary treatment system has been added to the effluent treatment process. Preliminary indications are that this system has increased the overall efficiency of the system.

ISSN:0315-1468    

DOI:10.1139/l86-067

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

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

ISSN:0315-1468    

DOI:10.1139/l86-068

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

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

ISSN:0315-1468    

DOI:10.1139/l86-069

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Following recent international consensus on a series of complex design formulae for the static strength of welded joints in hollow structural section (HSS) trusses, design aids and design procedures compatible with CAN3-S16.1-M84 and based on these recommendations have been produced for implementation in Canada. This paper formally illustrates the use of these design aids by undertaking design examples for rectangular hollow section (RHS) chord planar trusses. The design aids discussed by the writer are in the form of charts for manual design and an interactive microcomputer program for automated truss design. Although the design method is much more rigorous than that presently used by Canadian structural engineers, who typically follow the guidelines of the Stelco HSS connections manuals, it vividly illustrates to the user the principal parameters affecting the strength of welded joints in HSS trusses. The paper also demonstrates that the joint strength criteria frequently control the selection of members, thereby making the design and checking of such joints the responsibility of the design engineer rather than the fabricator.Key words: hollow structural sections, tubes, welded joints, trusses, limit states design, design aids.

ISSN:0315-1468    

DOI:10.1139/l86-070

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

This laboratory experimental study deals with dam-break flows on movable beds. It demonstrates significant differences between these wave parameters and values of the same parameters estimated on fixed beds. Moreover it is shown that under specific conditions some sediment transport models for steady flows can be applied to estimate bed erosion for this particular type of flow.Key words: dam, dam-break, break flows, erosion, laboratory tests.

ISSN:0315-1468    

DOI:10.1139/l86-071

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

This paper describes the structural design approach and the method of seismic qualification for an extra high voltage disconnect switch, a vital component in the substations of a power system network. Shaping and sizing of porcelain members of the frame received special attention to enhance their resistance to earthquake. A carefully developed finite element model, on analysis by response spectrum and time-history methods, showed acceptable seismic performance and an adequate margin of safety. Shake table tests for seismic qualification, called for by the specification, were not feasible owing to the large dimensions of the complete assembly. The alternative approach was to performin situmodal tests. By exciting the structure with a random force through a portable hydraulic exciter and using accelerometers to record the structural response, the dynamic characteristics of the equipment — the frequencies, mode shapes, and damping — were determined. Correlation between the results of finite element analysis and experimental modal analysis confirmed the validity of the analytical model. Application of combined analysis and testing for seismic qualification is demonstrated by a case study on an 800 kV disconnect switch.

ISSN:0315-1468    

DOI:10.1139/l86-072

出版商:NRC Research Press    

年代:1986

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l86-074

出版商:NRC Research Press    

年代:1986

数据来源: NRC