摘要:

This paper presents the electronic computer programmes used for the design of standard bridge superstructures by the SETRA (Service d'Etudes techniques des Routes et Autoroutes) of the French Department of Public Works. There is one particular programme for each bridge type. Through these programmes, concrete widths and depths and steel reinforcement are calculated for reinforced concrete beam and slab bridges, and prestressing is designed for prestressed concrete beam and slab bridges.Since February 1, 1962, 11 000 bridges have been designed with these varied and general programmes, suitable for most standard road and freeway overpasses. [Journal translation]

ISSN:0315-1468    

DOI:10.1139/l79-046

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

One of the tools used by the water resources engineer in developing operating strategies for water resources systems is operational hydrology—the stochastic modelling of a hydrologic phenomenon such as river flow in order to generate a large number of possible future occurrences of the phenomenon. This paper describes the selection and parameter estimation of a multisite multiseason model for application to five sites of a hydroelectric system operated by Alcan Smelters and Chemicals Limited in the Saguenay – Lac St-Jean region of Quebec. The model is used to generate synthetic inflow data and compute corresponding forecasts. The model is evaluated with respect to its ability to both generate realistic synthetic data and produce meaningful forecasts.

ISSN:0315-1468    

DOI:10.1139/l79-047

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The program package presented in this paper facilitates the computer-aided design of least-cost pipe distribution networks for any region in Canada. The design algorithms function in an interactive, conversational mode. Three algorithms—for analysing pressure and flow in networks, for computing the 'best' diameter of each pipe in the network, and for computing the best sizes of devices and materials to protect the pipes against freezing—were combined. Here 'best' is taken to be the least equivalent average annual cost.The pipe distribution network may include a wide variety of pipeline components and environmental constraints. The variables that determine the cost of pipe distribution networks in the extreme climatic regions of Canada are identified and their interaction for the many combinations of environmental, economic, and technological constraints are described.The computer program package was employed in the design of a minimum-cost distribution system for Broughton Island, Northwest Territories. The performance of the package indicated that it could be reliable, easy to use, and competitive in design cost.The package is locally accessible through a national computer network to dial-up terminals in or near most cities in North America.

ISSN:0315-1468    

DOI:10.1139/l79-048

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Today a majority of consulting engineers engaged in the structural design of buildings in Canada employ the computer as an aid to analysis and design. The behaviour and attitudes of these consultants toward the computer are reviewed here and the nature and extent of computer usage are discussed. This survey was carried out by means of a mailback questionnaire. Differences in usage between Canadian and American consultants are indicated.

ISSN:0315-1468    

DOI:10.1139/l79-049

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

This paper reviews the experimental data available in the literature concerning the effective width concept. The formulae for effective width that are contained in the AISI-68 and the CSA S136-74 specifications are critically discussed in relationship to the experimental data. The effective width is shown to be clearly a function of the actual width, in contrast to the constant value implied by the CSA S136-74 specification. A formula of the type used in the AISI-68 specification is found to be very suitable. It provides for reduced strength due to interactive effects in plates of moderate width to thickness ratios and places a limiting value on the effective width of very thin plates.A new design rule, of the simple formBe = 2 − 1/B, is proposed as an appropriate guide for the design of stiffened cold-formed steel plates.

ISSN:0315-1468    

DOI:10.1139/l79-050

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Compression-type single-shear plate–wood–plate specimens were used to measure the effect on the yielding mode capacity of single Griplam nails by increasing plate hole diameters from 1/4 in. (6.4 mm) to 9/32 in. (7.1 mm) and by decreasing steel-plate thicknesses from 1/4 in. to 3/16 in. (4.8 mm). Both changes reduced the load capacity; the effect of increasing hole diameter was greater. Table 49 of CSA Standard 086-1976 was confirmed as realistic, but slightly conservative. The reduction of capacity by use of 7 mm diameter holes in 3/16 in. plate was about 10%.

ISSN:0315-1468    

DOI:10.1139/l79-051

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The use of the natural ice cover in the Canadian high arctic for offshore petroleum exploration has made possible the drilling of 10 exploratory wells at very reasonable cost. The natural ice is thickened in the loaded area by flooding and freezing in thin layers and required ice thicknesses are obtained using theory for laterally loaded elastic, homogenous plates on elastic foundations. The suitability of this type of theory, which assumes linear strain distribution through the section and a neutral axis at the middle plane, has been questioned, especially since the ice behaves as a visco–elastic material and creeps or strains with time.Resistance strain gauges made of 3 m long, 0.127 mm diameter Teflon-coated wire have been used the last two winters to measure strains in the ice platforms. They have worked well and during the winter and spring of 1978 strains at five different levels in an ice platform beneath the heavier loads were measured and recorded continuously for 62 days. Strain profiles were linear with the neutral axis 0.4 m above the middle plane of the 7.1 m thick platform. Maximum measured principal strains were 1300 μϵ and maximum extrapolated extreme fibre strains were 2100 μϵ, confirming that the strains are small. Stress and effective elastic modulus values are shown to decrease rapidly in the early stages of loading.

ISSN:0315-1468    

DOI:10.1139/l79-052

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A two-continuous-phase sulfur–asphalt composite was developed for use as a road repair material. Two methods to obtain a continuous sulfur phase in a continuous asphalt phase are described. Scanning electron microscopy and mercury porosimetry technique provided evidence for a continuous sulfur phase. Mechanical properties—determined from hardness, uniaxial tension, and fracture energy measurements—of the two-continuous-phase sulfur–asphalt composite were studied at 22 and −31 °C. Mechanical properties of fiber-reinforced (up to 2% by volume of dacron fibers) sulfur–asphalt composites were also studied.

ISSN:0315-1468    

DOI:10.1139/l79-053

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Eskimo Point, Northwest Territories, is a predominantly Inuit community of about 900 people, located on the west shore of Hudson Bay. Formerly, its water supply was obtained from nearby small, sometimes polluted, shallow lakes, which freeze to the bottom in winter, necessitating an ice-cutting operation. In 1973, a study was undertaken to investigate alternative methods of improving Eskimo Point's water supply. The recommended solution was the construction of a 6 500 000 gal (29 548 350 L) earth fill reservoir, lined with a hypalon membrane.Further field investigations and detailed design of the facility were carried out in 1974. All long-term delivery items were pre-ordered, and a general contractor was selected through public tender. Utilization of local manpower and equipment was specified.Construction commenced in mid-June of 1975 with the contractor providing on-the-job training to local Inuit, who adapted quickly to the equipment. Within 2 weeks, an all-local labour force was working around the clock constructing the reservoir embankments. Placement of a membrane liner of approximately 3.5 acres (1.4 ha) took 1 week, and was followed by placement of a protective layer of fill over the liner. Through good cooperation among owner, supplier, contractor, and engineer, the reservoir was completed in the fall of 1975 in time to be filled with water from a lake approximately 1 mi (1.6 km) away.

ISSN:0315-1468    

DOI:10.1139/l79-054

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The difficulties and capabilities of mathematical models as applied to the problem of derivation of a detailed water quality management plan for the American portion of the St. John River are described. The international implications considered within the plan derivation are included.Specific attention is given to the iterative calibration efforts undertaken as part of the utilization of mathematical models. The relative magnitudes of the nutrient regime sources as derived from nonpoint and point sources are characterized.

ISSN:0315-1468    

DOI:10.1139/l79-055

出版商:NRC Research Press    

年代:1979

数据来源: NRC