摘要:

A series of tests on W-shaped beam-to-column connections subjected to quasi-static cyclic loading was conducted to assess their ductility and energy dissipation capabilities. The specimens represent beams in ductile moment resisting frames undergoing alternating lateral loads. The aim of this study was to assess and compare the rotation capacity and energy absorption of locally web-stiffened beams with unstiffened beams. Of direct relevance to seismically designed moment resisting steel frames, the experimental results of this research clearly highlight the superiority of herring-bone style web-stiffened specimens over vertically web-stiffened or unstiffened specimens.Key words: earthquake, response, steel, moment resisting frames, stiffener, cyclic loading.

ISSN:0315-1468    

DOI:10.1139/l95-011

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

The primary objective of this project was to establish procedures necessary to improve and maintain the quality and performance of exposed residential concrete flatwork. While this classification of concrete is covered in the Canadian Standards Association specifications, the applicable sections are seldom enforced on the site. The project involved visits to 123 sites selected from the daily rosters of the six participating supply companies. At the sites a series of concrete tests were performed, and site conditions and finishing practices were observed and noted. The information collected for each site included the air content and slump of the concrete together with an evaluation of the site and finishing deficiencies. Compressive strength cylinders were taken at those sites as felt necessary. The project has demonstrated how a ready-mixed concrete supply industry can be organized in a cooperative effort and by way of a data feedback system involving drivers and plants to ensure that a quality product is repeatedly delivered and placed at job sites. The continuing education of all individuals involved in the total process is an important goal, particularly the finishing aspect. This paper is intended to meet part of this objective.Key words: residential flatwork, air content, field testing, workmanship, workability, compressive strength.

ISSN:0315-1468    

DOI:10.1139/l95-012

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

A study investigating the effects of temperature and organic loading on the performance of upflow anaerobic sludge blanket reactors was carried out in the laboratory. Laboratory-scale reactors of 3.2 L volume were semicontinuously fed a synthetic substrate consisting of beef consommé and macro- and micro-nutrient compounds. Temperatures ranged from 10 to 42 °C; organic loadings ranged from 2.0 to 30 kg COD/(m3∙d). Steady-state process kinetics and efficiencies were evaluated for the various conditions. Based on the assumption that upflow anaerobic sludge blanket reactor kinetics in the temperature range of 10–30 °C could be approximated by Monod and modified Arrhenius equation relationships, effluent SCOD concentrations and removals were used to determine the maximum rate of substrate utilization, the half-velocity constant, and the temperature coefficient. A design and operating chart was constructed based on the kinetic coefficients determined from the experimental data.Key words: upflow anaerobic sludge blanket reactor, temperature, loading, performance, kinetic

ISSN:0315-1468    

DOI:10.1139/l95-013

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

A better understanding of the dynamic behaviour of dams requires strong-motion instrumentations. In particular, it is necessary to observe the free-field motions at the dam sites and the effective motions along the abutments, and to determine the dynamic properties of dams and their response to severe earthquakes. Instrumentation schemes are developed for arch dams, gravity dams and embankment dams, considering specific observational needs and objectives. The technical specifications to be satisfied by the accelerographs and the arrays are developed. Four arrays, which have been installed in Swiss dams ranging in height from 120 to 285 m, for a total of 29 triaxial accelerographs, are also presented.Key words: earthquakes, strong motions, instrumentation, accelerographs, dams.

ISSN:0315-1468    

DOI:10.1139/l95-014

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

This paper presents an analytical investigation on the required separations between adjacent buildings to avoid pounding during earthquakes. Five wall buildings, having 3, 6, 10, 15, and 25 storeys, were designed for three different seismic zones in Canada: Montreal, Vancouver, and Prince Rupert. For each zone, an ensemble of code compatible ground motions was identified. Nonlinear time-step dynamic analyses were performed to determine the separations to avoid pounding between each building pair under each earthquake. The required separations, obtained by subtracting the time-histories of lateral displacements between adjacent floor levels, were compared with the requirements of the static method of the National Building Code of Canada. The results indicate that the static method of the code grossly overestimates the required separations. This is to be expected, since the static code procedure does not take full account of the intervening variables (periods, responses, and phases between building motions) which characterize the ground motion and building properties when determining the separation distances. A simplified spectral difference procedure is proposed for inclusion in future editions of the code.Key words: dynamics, earthquake, gap, pounding, seismic, separations.

ISSN:0315-1468    

DOI:10.1139/l95-015

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

The paper presents a simplified pseudostatic approach to model the nonlinear behaviour of the bottom plate in unanchored cylindrical liquid storage tanks for seismic applications. In this paper, the problem of axisymmetric uplift of the bottom plate is studied for tanks supported on both rigid and elastic Winkler foundations. In the analysis, the bottom plate is modelled by one-dimensional beam and two-dimensional plate models. By comparing the results, it is found that the one-dimensional beam model gives accurate results acceptable for all practical design purposes, in view of the many other uncertainties in the tank uplift problem. The analysis results also show that the support foundation flexibility may have significant effects on the uplift behaviour of the tanks. Based on the axisymmetric uplift results, the paper then presents a simple approach to model the seismic partial uplift problem of unanchored tanks by means of nonlinear springs. Modelling parameters for the nonlinear springs are generated for dynamic uplift response analysis. Sensitivities of the uplift behaviour and the nonlinear spring modelling parameters to the tank height-to-radius ratio and the soil stiffness are also studied.Key words: axisymmetric uplift, cylindrical tanks, earthquakes, pressure vessel, shell, soil effect.

ISSN:0315-1468    

DOI:10.1139/l95-016

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

An earthquake of magnitudeML = 4.3 occurred near Napierville, Quebec, on November 16, 1993. An accelerograph at the liquefaction, storage, and regasification plant of Gaz Metropolitain in Montreal, about 55 km from the epicentre, recorded the ground motion. Although the maximum accelerations and velocities from this event are small, the acceleration time histories do confirm the high energy content in the very short period range. The recorded ground motion and corresponding absolute acceleration response spectra are presented and various attenuation relationships, proposed for eastern North America, are utilized to compare the measured and predicted ground motion parameters.Key words: Napierville earthquake, attenuation relationships, acceleration spectra, strong motion records.

ISSN:0315-1468    

DOI:10.1139/l95-017

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Nonlinear seismic analyses of a 90 m high concrete gravity dam, assumed to be located in eastern Canada, have been conducted using a smeared crack finite element model. Reduced frequency-independent added matrices have been used to represent the hydrodynamic and foundation interaction effects. Parametric analyses have been performed to assess the effects of the initial conditions induced by severe winter temperature, and the effects of hydrodynamic and foundation interaction mechanisms, on the nonlinear seismic behaviour of the dam.Key words: gravity dams, nonlinear seismic response, finite element, crack propagation.

ISSN:0315-1468    

DOI:10.1139/l95-018

出版商:NRC Research Press    

年代:1995

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l95-019

出版商:NRC Research Press    

年代:1995

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l95-020

出版商:NRC Research Press    

年代:1995

数据来源: NRC