摘要:

A strength increase of 20% was obtained by offsetting the diagonals in prestressed latticed cantilever models loaded at their ends. The purpose of this paper is to describe the research leading up to and including the model tests that provided these strength increases. The paper considers theoretical problems and suggests an outline for further research. At the present time it is important to develop an analytical framework to predict the behaviour of structures that incorporate the concepts of this research.

ISSN:0315-1468    

DOI:10.1139/l80-071

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The study of current work on steel code calibration shows that uncertainties in member resistances, load effects, and structural analysis are most usually assumed to have mean values equal to unity. The risk of failure that would result from the apparent safety index is higher than borne out by experience. Perhaps more important is the fact that it is necessary to assume elastic and determinate properties. These restrictions are removed if the various uncertainties are examined separately. It is then shown that their combined effect leads to a global uncertainty of a random nature, whose mean value is less than 1.0. The actual risk of failure is 5–10 times lower than the apparent one.

ISSN:0315-1468    

DOI:10.1139/l80-072

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The results of extensive site observations of weathering patterns (defined as staining, discoloration, or the like) of building façades in a city environment are presented. A primary objective of the research is to determine the relationship between profile variations of precast concrete wall panels, water flow, and resulting weathering patterns. A comprehensive classification of panel shapes arranges panels with common shape characteristics and staining patterns. General categories of projecting frames, flush or punched openings, heavily sculptured, and plain types are analyzed with respect to both large-scale and small-scale staining patterns. An analysis of design details that influence staining patterns is included. Moreover, investigations for a preliminary mathematical model of water runoff over façade surfaces are also described. Finally, a number of pragmatic recommendations are established to guide panel designers.

ISSN:0315-1468    

DOI:10.1139/l80-073

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

This paper presents the results of full-scale field tests on two steel guyed latticed towers. The towers were approximately 83 m in height, were guyed at three levels, and were of bolted angle construction. The observed results consist of the natural frequencies of the first two modes of vibration as well as the damping ratio for the first mode. The observed results are compared with analytical predictions and observations made concerning the contributions of structural and cable action to the damping ratio.

ISSN:0315-1468    

DOI:10.1139/l80-074

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

A new approach to the study of domestic wastewater equalization basins is presented. The proposed methodology is based on the continuous simulation of the process using CSMP/360 (continuous system modeling program) simulation language. Different operating conditions can readily be simulated by the model EQUIL during a single computer run. This feature permits the construction of various response curves from which the volume of the equalization basin can be determined so as to meet the specified effluent variations. Two examples illustrate the use of the model for design purposes.

ISSN:0315-1468    

DOI:10.1139/l80-075

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The design difficulties for rigid sewer pipe and timber pile supports in low-strength soils are reviewed. A proposal is developed to serve as a rational basis of design for assessing vertical and horizontal loads, pile and pile cap selection, flexural design and strength of the pipe to resist vertical loading, pile fixity, and pile column design. Examples of the calculation procedure are given and conclusions by others based on field testing of flexurally reinforced pipe are presented.

ISSN:0315-1468    

DOI:10.1139/l80-076

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Concise design recommendations are given relating to the design of W-shaped beams for building structures when it is necessary to provide large web openings. These recommendations are followed by a commentary describing the background to each of the recommendations, and references are given that will be useful for designers who wish to treat situations beyond the scope of the recommendations presented.

ISSN:0315-1468    

DOI:10.1139/l80-077

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

This note examines in some detail the design snow loads on simple arches and curved roofs recommended in the 1977Commentary on Snow Loadsof the National Building Code of Canada. Empirical modifications that give more appropriate unbalanced snow loads for large-radius arches and that will alleviate the problems caused by some overconservative aspects of the 1977 design loads are presented. They have been accepted for inclusion in the 1980 commentary.

ISSN:0315-1468    

DOI:10.1139/l80-078

出版商:NRC Research Press    

年代:1980

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l80-079

出版商:NRC Research Press    

年代:1980

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l80-080

出版商:NRC Research Press    

年代:1980

数据来源: NRC