摘要:

Annoyance criteria are derived for walking vibrations of long-span floors. The criteria are developed primarily for steel beam or joist construction with concrete deck, spans greater than about 25 ft (8 m) and natural frequencies less than about 10 Hz. The criteria are expressed in terms of the dynamic properties of a floor as measured by a heel impact test. The advantage of the heel impact test is that it provides a tool for design calculation.

ISSN:0315-1468    

DOI:10.1139/l76-017

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

This paper presents the design and development of moment connections between wide flange beams and square tubular columns in rigid frames. The connection is effected by means of coped strap angles used to transfer stress from the beam flanges to the sides of the column. The testing program comprised 23 specimens, including two standard rigid joints introduced to give a comparison basis for thecurves.The results indicate that after adequate precautions have been taken to prevent the occurrence of brittle fracture in the strap angles a connection is obtained which can developMPand sustain appreciable inelastic deformation, making it suitable for plastically designed frames. The rigidity of the connection is less than that of a standard connection but high enough for the joint to be termed 'nearly rigid'. Preliminary theoretical studies indicate that the effect of the relative loss of rigidity on the sway behaviour of multistory frames may be significant and thatP-Δ effects should be investigated.All joints considered here comprised beams of flange width equal to that of a column face.A design method is proposed in the Appendix.

ISSN:0315-1468    

DOI:10.1139/l76-018

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The effect of imperfections on the maximum strength of isolated, simply supported biaxially bent steel H-columns is studied with the help of a computer program. The influence of the pattern and intensity of residual stresses is considered first. The effect of the sign and magnitude of initial crookedness is then examined. Finally, the variation of the influence of residual stresses and initial crookedness with slenderness is presented. It is indicated that the numerical results given and the computer program, could be used to check the validity of the existing design methods, after selecting the representative imperfections.

ISSN:0315-1468    

DOI:10.1139/l76-019

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Weibull's theory of brittle fracture is applied to the determination of strength of Douglas-fir wood in longitudinal shear. Ultimate stresses, at a given survival probability, are derived for beams under different loading conditions. The theory allows an explanation for the difference in shear strength between beams and the standard American Society for Testing Materials shear block, as well as for the dependence of shear strength upon beam size. The theory is verified by comparing theoretical predictions and test results on Griplam nailed connections loaded parallel to the grain and shear tests on torque tubes. Very good agreement is shown. Finally, allowable shear stresses for beams under different loading conditions are derived.

ISSN:0315-1468    

DOI:10.1139/l76-020

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A mathematical model has been developed which can aid in assessing the effect of the modification of land use patterns on the water quantity and water quality regime of a watershed. The basin under study is divided into a number of elements using a square grid technique. The hydrologic and water quality components are evaluated at each element in the basin at successive time intervals, and flows are routed through the elements by use of a streamflow network system. The model can be used to assist in evaluating the effects of alternative land use configurations in a watershed, such as urbanization, the removal or growth of forests, the construction of dams, etc., on water quantity and water quality. It can also be used in the preliminary design of an urbanized area to estimate the size of storm sewers, artificial ponds, etc.

ISSN:0315-1468    

DOI:10.1139/l76-021

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A new numerical technique is described by which the process of creep bending under transient heating conditions can be predicted. It utilizes a convenient creep model, proposed by Dorn and expanded by this author.The computer simulation of the behavior of three protected steel beams during standard fire tests is discussed. The close agreement between the experimental and computed midspan deflection histories is regarded as the proof for the accuracy of the technique as well as of the creep model employed.

ISSN:0315-1468    

DOI:10.1139/l76-022

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

In a recent study of the feasibility of developing a marine terminal at Grande Ile, Quebec, in the St. Lawrence Estuary, the economic influence of winter ice conditions on shipping schedules was a major uncertainty. Data on ice conditions were available from several years of operation of aerial ice reconnaissance programs. An abstract of these records was used in the derivation of estimates of vessel delays.Passage time statistics were estimated by numerical simulation of the passage of vessels from the Atlantic Ocean to this site for the full range of conditions which have been observed. By these calculations the severity of ice conditions was expressed in the terms of delay, a factor which has direct economic implications. The distribution of risk of delay over the winter season and the probabilities of total delay affecting cargo inventories were derived.Since the same basic information on prevailing ice conditions is available for most Canadian navigable waters, this approach might find more general application. The greatest weakness in the approach at present lies in the data on the resistance imposed by ice. A program of data gathering to improve the empirical basis of the speed loss estimates is suggested.

ISSN:0315-1468    

DOI:10.1139/l76-023

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Derivation of a design hydrograph from rainfall data is a typical problem when dealing with small catchments; in most cases there are no streamflow data available. Numerical solutions of unsteady flow equations are difficult to adopt for flow on natural catchments because of the uncertainity about the initial and boundary conditions. A simplified approach is suggested in which a catchment topography is characterized by a number of planes and channels. Flow over the planes and the channel flow are computed by a numerical solution of the state variable equations of unsteady gradually varied flow. The state variable model of surface flow offers simplicity and calculating speed compared with the numerical solutions of the complete unsteady flow equations, yet it maintains a reasonable approximation of the physical reality. Example problems of the use of the model in derivation of a design hydrograph for a small catchment, using rainfall intensities and durations as inputs, are presented. The computer program is provided at a nominal charge from the Depository of Unpublished Data, CISTI, National Research Council of Canada, Ottawa, Canada K1A 0S2.

ISSN:0315-1468    

DOI:10.1139/l76-024

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Major earthquakes have been observed to damage marginal wharf gravity retaining structures or walls throughout the world, and earthquakes of similar magnitude occur quite often in Canada. These earthquakes generally take place in the British Columbia coastal areas, the St. Lawrence Valley, Baffin Island, and the Yukon Territory. Elsewhere, normally designed marginal retaining structures should have adequate factors of safety to withstand anticipated seismic loads. However, in earthquake-prone areas it is recommended that most marginal retaining structures be designed using the seismic coefficient method. While not all aspects of the suggested seismic design procedure are developed, detail is provided on seismic exposure at the site, earth pressures due to earthquake conditions, and recommended factors of safety for short-term conditions. Design aspects of a more specific geotechnical nature (soils investigation, liquefaction, remedial measures, tsunamis, and backfill specifications) are indicated.

ISSN:0315-1468    

DOI:10.1139/l76-025

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The details of an experimental hydraulic study on a scale model of a particular type of spillway for the Savage Mills dam project on the Yamaska River near Granby in the Province of Quebec are presented. This multipurpose dam is a joint project between the Office of Planification and Development of Quebec and the Natural Resources Department of the Province of Quebec. Preliminary studies have shown that the use of a standard type of spillway such as a shaft spillway or a side channel spillway would be less economical than a structure that would make use of the diversion channel which is usually only a temporary work. A particular type of spillway, being a combination of the side channel and shaft spillways which discharges into the diversion channel, has then been proposed by engineers of the Department of Natural Resources. In order to evaluate the capacity, the operation and the efficiency of that structure, a scale model study has been carried out. That study has established the hydraulic properties of the proposed structure and has enabled one to properly design its different components.

ISSN:0315-1468    

DOI:10.1139/l76-026

出版商:NRC Research Press    

年代:1976

数据来源: NRC