摘要:

Development of a lignite deposit at Onakawana in northeastern Ontario requires extensive drainage of the muskeg blanketing the proposed mine area. Dewatering of the muskeg is necessary prior to its stripping. Muskeg drainage systems must also efficiently handle surface runoff due to rainfall and snowmelt. A hydrological analysis of the muskeg and a hydrologic design for its drainage system are presented. Surface runoff quantities were estimated by means of the rational method and a kinematic wave model of overland flow. A modified Glover–Dumm equation was used to calculate the diteh spacing required for dewatering. A preliminary drainage system layout is discussed.

ISSN:0315-1468    

DOI:10.1139/l82-047

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

An empirical illustration of the adaptability of transportation systems as it is reflected in drivers' gap acceptance behaviour is presented. Field surveys were undertaken at several uncontrolled urban intersections that were carefully selected in order to clearly show the response of drivers on minor roads, in their gap acceptance behaviour, to varying traffic flows on the main roads. The collected data were initially examined in an aggregated form. In addition, the data were subdivided according to flow categories observed on the main road and examined individually. Results from the latter show that critical gaps decrease monotonically with increasing flow on the main road. When the results from the aggregated and disaggregated analyses were compared, discrepancies exceeding 100% were obtained for the estimated critical gaps as well as for the computed probability densities of critical gaps over the population of drivers. It appears that results from the disaggregated analyses, which give greater insight into how drivers on minor roads adapt to varying traffic flows on the main roads, affirm the view that improved understanding of drivers' gap acceptance behaviour can be realized by taking adaptive features into account.

ISSN:0315-1468    

DOI:10.1139/l82-048

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Rural highway capacity, level of service, and other planning criteria are based on outdated information from the United States where the operating environment and traffic conditions are often quite different from those in Canada. Much of the information on rural two-lane highway overtaking and capacity in the 1965Highway Capacity Manual(HCM) can be traced to data collected as long ago as 1938. Rural two-lane highway capacity and overtaking concepts in use today have remained essentially unchanged since they first appeared in the 1950Highway Capacity Manual.This paper presents the findings of an investigation into speed–volume relations, platooning, and overtaking on the primary two-lane rural highway system in Alberta, British Columbia, and the National Parks.The principal findings are: (i) there is little relation between speed and volume over the range of volume observed — up to 1700 vehicles per hour, (ii) the average speed at 1000 vph was found to be 20–25 km/h higher than that predicted in the HCM, (iii) the backward bending portion of the speed–volume curve was not observed, (iv) speed distributions at flow rates of 1200 vph showed a marked increase in speed over that in the HCM, and (v) speed distributions of free-moving vehicles indicate a higher proportion of vehicles travelling at uniform speed.The implication of the findings is that the level of service on two-lane rural highways is much higher than that given in the HCM. This, however, is not the case on most of the primary two-lane highway system in western Canada. Despite low volumes, in the 2500–5000 average daily traffic range, drivers perceive a low level of service. This is attributed to a high proportion of long distance (over 300 km), high-speed trips, in rolling terrain with restricted sight distances, through sparsely developed territory with few intermediate stops. Thus motorists spend most of their journey travelling in high-speed platoons resulting in a high driver workload and a propensity to take risks when overtaking.The paper concludes with a recommendation that a nation-wide effort be mounted to collect speed–volume, headway, platooning, and passing data over the full range of highway operating conditions on a year-round basis. A second recommendation is that provincial highway departments in Canada investigate the concept of platooning and opportunity to overtake for evaluating their two-lane highways. More attention should be given to the education and testing of drivers in the skills of overtaking on rural highways. Also proposed is an evaluation of currently accepted, safe passing sight distances, which may be inadequate for the current operating conditions and traffic mix. Alternatives to four lanes, such as alternating passing lanes with early warning signs (to inform the driver of overtaking opportunities a specified distance ahead in order to reduce driver frustration and prevent dangerous passes), need evaluation as well. The paper concludes with a comment on the possible impact of lower speed limits and vehicle control devices, such as the cruise control, on platooning, overtaking, and level-of-service measurement.

ISSN:0315-1468    

DOI:10.1139/l82-049

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

A finite element technique based on an incremental tangent stiffness method is employed herein to analyze the behavior of welded truss connections subjected to combined tension and shear. A computer program named ELAPLAS (ELAsto-PLAStic finite element analysis) is developed to simulate the load–deformation behavior and to predict the ultimate tensile capacity of a structural tee in a welded truss joint subjected to a prescribed transverse shear load. Analytical studies were carried out to investigate the interaction of tension and shear in welded truss connections. The analytical results obtained are compared with available test data to verify the validity of the proposed finite element technique. Results of parametric studies are presented to illustrate the significance of various design parameters in welded truss connections. Such parameters as material properties, thickness variations of structural tee web and flange, and the truss configurations are investigated. As a result of the present work, simple interaction equations of combined tension and shear are developed and suggested for design office use.

ISSN:0315-1468    

DOI:10.1139/l82-050

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Splitting tension tests of concrete block masonry specimens were used to investigate the in-plane tensile strength of concrete block masonry. The strength and geometric properties of the blocks and of various strength grouts were included as test parameters. Explanations for the observed behaviour were suggested. In addition to providing test data for evaluating current design provisions for tension produced by combinations of in-plane loads, documentation of the relative influence of grouting is an important objective of this paper. The results indicate inconsistencies with the current design assumption that grouted blockwork is equivalent to construction with solid units. Some general conclusions related to design provisions are provided.

ISSN:0315-1468    

DOI:10.1139/l82-051

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

In this paper representational data are given that can be used for the planning of single-span prestressed bridge construction. The project-network is represented, together with the critical path and time–cost relation, which has been calculated. Schedules for manpower and equipment required for project completion are also shown, as well as the owner's cash flow. The application of such data to construction of similar projects in different locations and/or in the future is discussed. The bridges under consideration were constructed using precast, prestressed concrete beams and the deck was castin situto act compositely with the beams. To establish these data, the daily work reports and progress payment certificates of five bridges, built in southern Ontario between 1976 and 1980, have been analyzed. Average values, based on the data of the five bridges, were utilized in this analysis.

ISSN:0315-1468    

DOI:10.1139/l82-052

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

This paper documents the assumptions and analyses made in the derivation of resistance factors for reinforced concrete design compatible with the load factors in the National Building Code of Canada. Based on existing data on the variability of concrete and steel dimensions, statistical estimates were made of the variability of the strength of reinforced concrete members. These data plus statistical descriptions of loadings were used in a first-order, second moment analysis to compute resistance factors. These have been proposed for inclusion in the CSA A23.3 Code and are currently under study by the CSA Technical Committee on Reinforced Concrete Design.

ISSN:0315-1468    

DOI:10.1139/l82-053

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Civil engineering design methodology is changing as a result of emerging computer hardware and software. Highspeed, interactive, user-friendly systems are more common, whereas formerly batch submission of batch-oriented programs was the only common method. However, a variety of large, complex program packages are still widely used for urban drainage design problems. These packages are usually executed on mainframes with a large memory capacity and high computing speeds; users need a good working knowledge of FORTRAN input requirements and mainframe job control language, especially when the packages are used in a multi-program, multiprocessor environment. Furthermore, long learning times are associated with the implementation and execution of complex packages on batch-oriented mainframes at remote sites.This paper discusses the design of an interactive package of pre- and post-processors to facilitate input data preparation, job execution, output interpretation, and job resubmission in a multi-program, multiprocessor, remote batch environment. The pre-processors create input data files for job execution; the post-processors operate on the output from the simulation package, synthesizing, analyzing, and plotting to accelerate the users' interpretation at their terminals. The important advance in this work is that the original coding for the main, externally supported, batch-oriented package is not altered. Furthermore, local text processing using previously prepared, disc-based outline reports and the post-processor output allows direct production of draft reports.

ISSN:0315-1468    

DOI:10.1139/l82-054

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The stress distribution in steel plates welded at right angles to either I-section or rectangular hollow section members is notoriously nonuniform, leading to early failure of the plate, tube wall, or weld. The paper proposes an upper-bound approach that combines lócal punching shear with normal yield line analysis. The resulting expression for strength and branch efficiency is seen to be sensitive to the value of tube wall slenderness, and in reasonable agreement with a previously obtained efficiency expression based on a lower bound to test results. The theory also confirms the experimental observation that the width ratio between the plate and the rectangular hollow section does not have a significant effect on the efficiency of the connection. The theory presented enables a parametric study of the joint strength and efficiency to be made, and thus leads to a greater understanding of the behaviour of joints to hollow steel sections.

ISSN:0315-1468    

DOI:10.1139/l82-055

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Analytical techniques and the ability to simulate complex traffic situations have advanced to a state that now makes it possible to more accurately estimate the vehicle design load for bridges. A detailed road traffic simulation was developed to estimate the maximum vehicle loading over varying lengths of the Lions’ Gate Bridge. The simulation was generalized and used to develop vehicle loads used in the ASCE procedure.A sensitivity analysis indicated that the maximum truck weight and the percentage of trucks in the traffic stream were the two most important variables of the eleven used. The simulation method may be used for detailed load estimates on existing bridges as well as in the design of future bridges.Keywords: bridge live loads, traffic, trucks, computer simulation, traffic simulation, extreme value estimation

ISSN:0315-1468    

DOI:10.1139/l82-056

出版商:NRC Research Press    

年代:1982

数据来源: NRC