摘要:

This paper provides a general review of the basic principles for the structural design of the CN Tower. A discussion of the design is provided relating to each of the major portions of the structure. The following portions are treated separately and in relation to each other: concrete tower shaft; foundation; and upper accommodation building. Choice of geometry, materials, and construction methods is explained with respect to technical, architectural, and functional requirements and restrictions.

ISSN:0315-1468    

DOI:10.1139/l75-013

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Wave and ice forces are the main factors to be considered when designing offshore lighthouses. With the exception of the Pacific and the southern part of the Atlantic coasts, the design of the majority of Canadian lighthouses is governed by the ice forces. For many years very little was known about the magnitude of ice forces. Experience and judgement were the principal factors in the design and construction of such unique structures as lighthouses in the middle of a lake. Even now knowledge of these forces is not complete and there are still no Canadian design standards.Sloped surfaces and cylindrical or conical shapes are used for the substructures of the lightpiers and the ice-structure contact areas are designed as small as practical to reduce ice impact forces.

ISSN:0315-1468    

DOI:10.1139/l75-014

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

This paper deals with various sources of water supply in Ontario and the methods and relative difficulties of treating these sources. Sources include the Great Lakes, southern Ontario rivers and groundwater, and northern rivers and lakes. Distinctive characteristics with respect to hardness, turbidity, colour, chemical constituents, and biological and bacteriological content require specific treatment approaches for the provision of safe and palatable supplies. The effects of urbanization and industrial development are also discussed.The current approach to water treatment in Ontario is reviewed, as well as some of the historical developments leading up to the present state-of-the-art. Future requirements are touched on. Provincial water quality objectives are described and compared with international drinking water standards.

ISSN:0315-1468    

DOI:10.1139/l75-015

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The majority of communities in northern Canada lack piped water and sanitation services. In the permafrost region this is primarily because of the high costs associated with constructing above-ground piping conduits called utilidors.This paper examines the designs and costs of various utilidors in Inuvik, Northwest Territories, and outlines the necessary approaches to reduce costs and to improve performance of utildor-type systems. Technical innovation and establishment of performance standards are called for as a means of achieving these aims. Also, it is evident from the presented information that design engineers and utility system operators, in order to realize savings, should be keenly aware of cost–benefit relationships on a long-range basis.

ISSN:0315-1468    

DOI:10.1139/l75-016

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The main span of the four-lane highway Mission Bridge is 440 ft (134.1 m) long with 290 ft (88.4 m) flanking spans, and consists of a steel box girder with an orthotropic steel plate deck. A box girder was adopted due to the structural efficiency of the box section and advantages in using thin plate material. The design is based on CSA Standard S6-1966 and the AISC Design Manual for Orthotropic Steel Plate Deck Bridges as far as applicable and with some deviations. The design was reviewed subsequent to the failure of steel box girder bridges abroad. The strength of the bottom plate in compression and the transverse bolted joints in compression received special attention. The joints of the deck plate made in the field are welded.In the fabrication and erection of the bridge, advantage was taken of the marine location of the fabrication yard. Special erection equipment was developed for the job. A key element in the scheme was ease with which the erection crane scow could be positioned.The application of the hot asphaltic concrete paving caused considerable thermal expansion of the steel structure.The cost of the steel superstructure was about the same as was estimated for a concrete superstructure. However, site conditions were such that the weight of the concrete structure would have increased the foundation costs.

ISSN:0315-1468    

DOI:10.1139/l75-017

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Large-diameter piles socketed into bedrock support the abutments and piers of several large railway and highway bridges across the approach cuts of a tunnel near Welland, Ontario. The design of these piles was governed by the following considerations: (a) the large vertical and lateral loads involved, (b) the low shear strengths of the overburden and the low design factor of safety of the slopes of the approach cuts, (c) the effect of the construction of piers and abutments on the stability of the slopes, (d) the development of negative skin friction on the piles at the abutments and some piers, (e) chemical and micro-biological attack on steel, and sulfate attack on concrete by the constituents of the groundwater, (f) the low shear strength of the gypsum in the bedrock and its tendency to creep, and (g) the possibility that gypsum might be leached out of the bedrock as the groundwater regime changes.The piles used varied from 24 in. (61 cm) and 30 in. (76 cm) in diameter for the highway bridges to 48 in. (122 cm) in diameter for the railway bridges. Where settlement of the overburden was expected to occur, only groups of vertical piles were used and these were coated with coal tar to limit the maximum value of negative skin friction. As these piles also were required to resist large lateral loads, the steel casings used in construction were designed to contribute to the structural strength of the piles and were protected from chemical and microbiological attack by a coat of an epoxy resin beneath the coal tar. The design took into account the lateral resistance of the overburden and, where it was insufficient, that of the bedrock. This type of pile was installed in an overexcavated hole and the casing was concreted several feet into bedrock; where bedrock conditions warranted it, the vertical load on the pile was transferred to the rock by the wedge action of a tapered socket.Where negative skin friction was not a problem, combinations of raked and vertical piles were used. The contribution of the casing to the strength of the piles was ignored and the casings were not protected. Tapered sockets were used on some of these piles where rock conditions were unsatisfactory.All concrete was sulfate-resistant, and for casings socketed into bedrock a method of installation was used that ensured intimate contact of concrete with the casings and the surrounding bedrock.

ISSN:0315-1468    

DOI:10.1139/l75-018

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Burton Bridge spans the Saint John River about 14 miles (~22 km) downstream from the city of Fredericton, New Brunswick, replacing a ferry service between Maugerville on the Trans-Canada Highway along the north bank of the river, and the township of Burton on the south side of the river. The ferry service, said to have been in use for over two hundred years, met with increasing criticism in recent years and a demand for its replacement by a bridge has resulted in the present structure, completed and opened to traffic in the autumn of 1972. The main span is an arch bridge with a center navigation span of 600 ft (182.9 m), and an overall length of 1026.5 ft (312.9 m), flanked on each side by three 125 ft (38.1 m) approach spans. The total length of bridge between the abutments is 1784.5 ft (543.9 m), and its greatest height above normal river level in summer is 185 ft (56.4 m). Access to the bridge from the existing roads is accomplished by approach roads on new embankments, the one on the south side being relatively short, while those on the north bank form a complex of roads providing east and west access to the Trans-Canada Highway, over which a pre-stressed concrete overpass bridge has been built for one of the routes.

ISSN:0315-1468    

DOI:10.1139/l75-019

出版商:NRC Research Press    

年代:1975

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l75-020

出版商:NRC Research Press    

年代:1975

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l75-021

出版商:NRC Research Press    

年代:1975

数据来源: NRC