摘要:

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.

ISSN:0315-1468    

DOI:10.1139/l79-001

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The design of light-gage steel corrugated shear diaphragms is not yet covered by the structural codes of many countries, including Canada. The shear capacity of steel diaphragms may be predicted by various approaches currently available, namely, those proposed by: (1) the American Iron and Steel Institute; (2) the Manual of seismic design of buildings, published by the U.S. Departments of the Army, Navy, and Air Force; and (3) the recommendations outlined in the current British code. In this paper, a rational method is proposed and the application of all the above methods is illustrated with reference to a specific example. Finally, the shear strengths of many diaphragms are predicted by the new approach developed by the authors and the results are compared to test data.

ISSN:0315-1468    

DOI:10.1139/l79-002

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

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.

ISSN:0315-1468    

DOI:10.1139/l79-003

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Designing for energy conservation in buildings calls for considerably better insulated roof structures than have been used and fire tested in the past. This requires that information be developed on the effect of such increased insulation on the temperature of structural steel and steel roof decks during a fire exposure.Fourteen small-scale fire tests are summarized that show that for combustible and noncombustible insulating materials a critical thickness exists beyond which additional insulation does not increase the temperatures developed on structural steel.

ISSN:0315-1468    

DOI:10.1139/l79-004

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A manual method for calculating the design live load longitudinal moments in superstructures of most right bridges is presented. The bridge types that can be analysed by this method are: slab bridges, beam and slab bridges incorporating both steel and concrete beams, bridges incorporating wooden beams, and slabs on hollow trapezoidal or other such torsionally stiff beams.The proposed method was developed by orthotropic plate theory, and was checked by the grillage analogy method. The basis of the method and details of development methodology are presented. The effect of the various parameters on the transverse distribution of longitudinal moments is discussed.The method is useful not only for the ease with which design longitudinal moments can be obtained, but also because it enables the designer to investigate the effects of making changes in the design on distribution characteristics.To demonstrate the simplicity of the solution a worked example is included.

ISSN:0315-1468    

DOI:10.1139/l79-005

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

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.

ISSN:0315-1468    

DOI:10.1139/l79-006

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The ultimate tensile strength requirements of Griplam nails (glulam rivets) were changed by the 1976 edition of CSA Standard 086. This action reduced the working loads for the nail-yielding mode of connection failure by 8%. To verify that the adopted factor of safety against yielding was retained, 12 large connections varying in predicted tensile capacity from 42–126 kips (187–560 kN) were tested. A bending specimen was chosen that served very well in three of the four load levels. The tests confirmed the predicted ultimate capacity of 1400 lbf (6230 N) per nail for a 3 in. (76 mm) or more penetration of dry Douglas-fir wood with loading parallel to grain. Other related aspects are discussed.

ISSN:0315-1468    

DOI:10.1139/l79-007

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

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.

ISSN:0315-1468    

DOI:10.1139/l79-008

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

This paper briefly describes the salient features of automated warehouses as they affect the structural engineer. The two basic types, a separate building and rack structure and an integrated rack – building structure are discussed. The effects of pallet type, tolerances, loading, and rack standards on the structural framing are considered.

ISSN:0315-1468    

DOI:10.1139/l79-009

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

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.

ISSN:0315-1468    

DOI:10.1139/l79-010

出版商:NRC Research Press    

年代:1979

数据来源: NRC