摘要:

A study is made of the feasibility and usefulness of a seismic design method for multistorey steel-frame buildings. The method employs a time-series elastic response analysis of the structure for a ground motion compatible with a design response spectrum. The correlation between the elastic and elasto-plastic response is investigated and it is suggested that the design forces in the members of an elasto-plastic structure can be obtained by applying appropriate reduction factors to the forces obtained in an elastic analysis.A design example is presented in which a multistorey steel-frame building with a rather large setback is designed for seismic forces by using the results of an elastic dynamic analysis for a selected ground motion and reducing the forces so obtained by applying one uniform force reduction factor to all girder moments and another, a smaller one, to all column moments and axial loads.

ISSN:0315-1468    

DOI:10.1139/l79-018

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Since the early sixties, considerable effort has been made to collect information on the hydrological regimes of the rivers of northern Quebec. It is during that period that most of the gauging stations were put into operation and therefore, after 15 years of record, we have in hand enough data to get a better understanding of the different conditions prevailing on these rivers.This part of Quebec is characterized by flat ground and low precipitation and so we could expect a light runoff. On the other hand, the great number of lakes and marshes of the region contributes to the lamination of floods and the increase of the low flows.The hydrological study concerns mean flows, water balance, seasonal variations, low flows, and floods. To realize these studies, we have chosen more than 30 stations located in the regions of James Bay, Hudson Bay, and Ungava. The record period varies from 12 to 15 years (1960–1975).

ISSN:0315-1468    

DOI:10.1139/l79-019

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A two-stage mathematical model is developed for predicting dissolved oxygen levels in ice-covered rivers. The first stage of the model is a prediction model for ice-edge progression as a function of time, and the second stage consists of an extrapolation of a widely used 'summer condition' water-quality model. The results of a series of experiments, both field and laboratory-based, which served as data input generators and calibration testing of the model, are provided.Briefcase-study applications of elements of the model to the Speed River and to the Saint John River are included.

ISSN:0315-1468    

DOI:10.1139/l79-020

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The Edmonton–Calgary corridor transportation study is an example of multimodal intercity passenger transportation planning in a low-density corridor. This represents a departure from most corridor studies, which have been conducted in the most intensively travelled and densely populated regions. The study provided the background data, information, and analysis to facilitate transportation planning in the Edmonton–Calgary corridor region. A wide range of capital-intensive alternatives (particularly for the rail and air modes) and a number of transportation system management alternatives are related to transportation issues in the corridor region in a multimodal systems analysis framework.This paper discusses a number of unique approaches used in the study that were the result of the need to deal with the low-density aspects, the need to consider both regional and intercity travel, and the inherent design of the study. These include its iterative approach to the analysis, its handling of the demand and cost analysis, its consideration of multimodal impacts, and the emphasis on identifying key issues and resulting strategic choices. The success and drawbacks of these methodologies are reviewed.The paper also reviews the major findings of the study, many of which can be extended to a more general context: a competitive market analysis may be of little interest in low-density regions; new technologies tend to bias even further the imbalance between intercity and regional transportation service; the automobile has a key role to play in regional transportation; for many transportation needs the intercity bus is an economical and efficient mode; and an improved rail service is an uncertain and long-term venture, which could detrimentally affect all intercity bus service in the region.

ISSN:0315-1468    

DOI:10.1139/l79-021

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Budgetary constraints have initiated development of several schemes for establishing roadway-improvement priorities. Inherent in most of these programs is a technique for identifying the most appropriate roadway locations requiring improvements. In the past, except for situations where capacity limitations are evident, safety has generally been the criterion used to justify roadway improvements. Therefore, those roadway locations that are relatively the most hazardous and most susceptible to improvement must be identified.Quality-control techniques were first applied for this identification purpose over 20 years ago. However, most applications have been associated with accident-number or accident-rate data. Use of accident-severity criteria in quality-control methods is still vague. This paper provides an overview of existing identification techniques. Further, by defining severity as the ratio of fatal and injury accidents to all accidents, a severity quality-control technique for identifying hazardous roadway locations is presented. This technique incorporates both accident-rate and accident-severity criteria.

ISSN:0315-1468    

DOI:10.1139/l79-022

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Some structural components of bridges can be idealized as cantilever slabs in isolation, for the purpose of analysis. Usually a realistic analysis of such components, when subjected to concentrated loads, is done by methods that are either computer-based or too complex for everyday design application. A semi-graphical manual method for the analysis of semi-infinite cantilever slabs is presented as an alternative to rigorous solutions.The method presented supplements an earlier published manual method for the analysis of infinitely wide cantilever slabs.

ISSN:0315-1468    

DOI:10.1139/l79-023

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Research carried out on light-gage metal shear diaphragms clearly indicates that the shear behaviour depends mainly on the behaviour of the fasteners. There is no generally accepted theory to predict the shear stiffness and strength of diaphragms with welded connections, even though there exist some approximate methods for the case of diaphragms with mechanical fasteners. Simplified formulas are presented in this paper for calculating the shear stiffness and strength of metal shear diaphragms. The analysis is based on the observed deformation pattern of the panels and on the failure mode of the fasteners. By using the test data of the fasteners, the shear characteristics of many diaphragms are predicted and compared with the test results. It is of interest to note that the proposed formulas are suitable for diaphragms with any types of fasteners. Because of their generality and simplicity, the theory would be extremely useful for design engineers.

ISSN:0315-1468    

DOI:10.1139/l79-024

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

This paper contains a general study on the natural clogging of porous media by suspended sediment in water. This creates with time a decrease in the permeability coefficient and consequently a reduction of the seepage flow.Two theories are presented and compared for the prediction of the rate of clogging in nature. The two approaches have been verified by experimental data obtained from tests carried out at Laval University. Results have permitted the limits of application of each method to be denned.

ISSN:0315-1468    

DOI:10.1139/l79-025

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

This paper collects together relevant information and develops a methodology to control construction loads in multistorey buildings taking into consideration member gain in strength with age and temperature.Many multistorey buildings are constructed by casting on to forms that are in turn supported on the previously cast lower floors in the building. The loads imposed upon these recently cast supporting floors during construction may exceed the strength capabilities of these floors. The strength capabilities of the concrete structural elements are dependent on age and curing temperature, which must be considered in the design of any construction schedule.One conclusion drawn from the method is that the greater the number of forms used the greater the construction load applied to the slabs. Hence, it is recommended that only one level of forms plus reshores be used for all multiform construction.During the form-stripping–reshoring operation it is necessary that at least a complete bay and preferably a complete floor be cleared of forms before any reshores are installed.

ISSN:0315-1468    

DOI:10.1139/l79-026

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

An experimental investigation is made of the influence of cropping, a relatively new fabrication procedure, on effective-length factors for round tubular steel struts. Tests of 18 companion pairs of cropped and sawn strut specimens, with end plates providing various degrees of end-fixity, are described. The Southwell plot method, using both transverse displacements and strains, is used to determine elastic buckling loads. These are in turn used to compute effective-length factors. Those for the sawn specimens approach 1.0 for very small end-fixity and 0.5 for large end-fixity. Except for the specimens with very small end-fixity, the effective-length factors for the cropped specimens are approximately 15% larger than those for the corresponding sawn specimens.

ISSN:0315-1468    

DOI:10.1139/l79-027

出版商:NRC Research Press    

年代:1979

数据来源: NRC