Search

In January 2002, the Intelligent Sensing for Innovative Structures (ISIS) Canada Networks of Centres of Excellence announced its first pedestrian bridge design competition for ISIS students. The bridge is located on the campus of the Université de Sherbrooke to provide a new access to the new east entrance of the Faculty of Engineering Building. The proposed design was required to convey the innovation and ingenuity of the ISIS Canada Research Network through the use of fibre-reinforced-polymer (FRP) materials. Based on these requirements, five graduate students from the Department of Civil Engineering at Queen's University joined forces to produce the winning conceptual design, demonstrating cost-effectiveness, visual stimulation, and innovation. This application paper presents details of the competition and the winning design for the pedestrian bridge as told by the winning design team. The bridge was built during the summer of 2002 at the Université de Sherbrooke. The objective of the paper is to present the student experience from this highly successful competition, and thus to promote similar design competitions for engineering students. [ABSTRACT FROM AUTHOR]

This paper describes the development of the 2004 Canadian Standards Association (CSA) A23.3 shear design provisions for reinforced and prestressed concrete structures. These methods are similar to the 1994 standard in providing a simplified and general shear design method. They differ from previous standards by providing a direct link between these two methods and simple equations for the calculation of β and θ used in the general method rather than providing these values in a table. The paper explains the basic assumptions behind the new shear provisions, provides a derivation of the new equations, and compares designs made with the new equations to designs obtained from previous standards. In general, the new shear provisions require slightly less shear reinforcement than that required by the previous standard. The new general method is significantly easier to use, particularly with spreadsheets. [ABSTRACT FROM AUTHOR]

In this study, the equation for the punching shear strength prescribed in the Canadian code is evaluated based on a database of experimental results. This paper also includes a discussion of the effect of several parameters on the punching shear strength in the Canadian and European codes. The experimental work presented includes testing of ten full-scale two-way slabs with different reinforcement ratios to examine the effect of reinforcement ratio on punching shear capacity. A simplified practical punching shear equation is also proposed based on statistical analysis of experimental results from the database. Statistical regression analysis is conducted on 190 test data available in the literature to evaluate the influence of reinforcement ratio on punching shear strength. The proposed equation accounts for the effect of slab depth using fracture mechanics concepts. The analytical study showed that the reinforcement ratio has a strong influence on punching shear strength. The proposed equation could be an alternative to the current punching shear equation used by Canadian Standards Association CSA-A23.3-04 design code. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the new provisions for the design of coupled shear walls in Canadian seismic zones. It follows major revisions that were incorporated in the National Building Code of Canada 2005 (NBCC 2005) and in the Canadian standard Design of concrete structures (CSA A23.3-04), which were due, in particular, to the adoption of a new Canadian map of seismic risk. The present study is intended to address recurring confusions in current practice and the difficulties expressed in the application and interpretation of the new NBCC 2005 and CSA A23.3-04 provisions. A design flowchart is thus proposed as a practical guide, describing, step by step, the required verifications at each stage of coupled shear walls calculation. Finally, to demonstrate the applicability of these new provisions, a numerical example is detailed, following the presented design flowchart. [ABSTRACT FROM AUTHOR]

This paper presents a laboratory investigation on the durability and structural performance of carbon fibre reinforced polymer (CFRP) - reinforced concrete (RC) slab specimens extracted from the Laurier-Taché Parking Garage (in the National Capital Region, Canada) after being subjected to service field conditions for about 8 years (1997-2005). The laboratory investigation comprised two phases. The first phase evaluated the durability of the CFRP bars, the concrete, and the interface between the two materials by conducting microstructural and chemical analyses on core samples extracted from the slabs. As part of this phase, five CFRP bar samples were extracted and tested in tension to investigate if the CFRP bars experienced any degradation in strength or stiffness. The second phase investigated the structural behaviour of the slabs by testing four slab segments (3.0 m long × 1.0 m wide × 0.2 m deep) in flexure. Test results showed that neither the CFRP bars nor the CFRP-RC slabs have been adversely affected after being in service for 8 years. [ABSTRACT FROM AUTHOR]

Full-scale tests provide valuable information on the characteristics of building structures that can be used to evaluate design methods, to calibrate modelling techniques, and to determine damage corresponding to loading levels. These tests are scarce due to the enormous requirements in testing space and specialized testing equipment. The seismic behaviour of a full-scale, two-storey, reinforced high-performance concrete building designed with moderate ductility detailing is evaluated by pseudo-dynamic testing, during which increasing seismic loads are applied, resulting in increasing levels of permanent damage to the structure. To monitor the level of damage, a series of successive forced-vibration tests are also carried out at each step of the process and are used to track changes in the key dynamic properties of the building. The paper presents the design of the test structure according to the new edition of the CSA A23.3-04 Design of concrete structures standard, the series of pseudo-dynamic tests simulating different levels of earthquake excitation consistent with the 2005 edition of the National building code of Canada, and the evaluation of the performance of the building. It is shown that the detailing requirements of CSA A23.3-04 are more than adequate to provide the ductility and overstrength expected. Les essais à grande échelle fournissent des informations importantes sur les caractéristiques des structures pouvant être utilisées pour évaluer les méthodes de dimensionnement, pour calibrer des techniques de modélisation, et pour déterminer l'endommagement correspondant à des niveaux de chargement. La rareté de ces essais est due principalement à la nécessité de disposer de grands espaces de laboratoire et d'équipements d'essais spécialisés. Dans cet article, le comportement d'un bâtiment en vraie grandeur de deux étages est évalué par essais pseudo-dynamiques dans lesquels le bâtiment est soumis à des niveaux d'excitation sismique croissants causant des dommages de plus en plus importants à la structure. Le bâtiment est construit en béton à hautes performances pour posséder une ductilité modérée. Des essais en vibration forcée sont utilisées pour évaluer les changements dans les propriétés dynamiques de la structure. L'article présente le dimensionnement de la structure d'après la nouvelle édition de la norme CSA A23.3-04, Dimensionnement des structures en béton, la suite des essais pseudo-dynamiques simulant les différents niveaux d'excitation des tremblements de terre consistants avec le Code national du bâtiment du Canada 2005, et l'évaluation de la performance du bâtiment. On montre que les règlements de la norme CSA A23.3-04 sont tout à fait adéquats pour assurer le niveau de ductilité et de surcapacité désiré. [ABSTRACT FROM AUTHOR]

This paper presents the results of an analytical study on the nonlinear deformation and ductility response of reinforced concrete ductile coupled shear walls (CSWs) under seismic loadings. The CSWs were designed, calculated, and detailed in compliance with the National Building Code of Canada (NBCC) 1995 and the Canadian Concrete Standard CAN3-A23.3-94. The parameters and assumptions of the study as well as the description of the models and the procedure were fully described elsewhere. Results indicated that the maximum interstorey drift from dynamic analyses was well below that obtained from static analyses with NBCC specified lateral forces. It was also found to be substantially lower for tall CSWs compared to short or medium-height walls, and decreased only slightly as the degree of coupling increased within the range considered in this study. It was also highest for seismic records with low PGA/PGV ratios. Plastic hinge rotations as well as accumulated plastic hinge rotations generally decreased as the number of storeys increased. The maximum displacement ductility demand factor remained below the NBCC value of 4.0 specified for ductile CSWs. The influence of degree of coupling on the maximum displacement ductility demand factor was found negligible. Also, the maximum displacement ductility demand factor generally decreased as the number of storeys increased. The maximum rotational ductility demand factor in coupling beams decreased as the number of storeys increased and was generally less than the practical accepted limit of 10, except for a few short CSWs.Key words: coupled shear walls, reinforced concrete, seismic, degree of coupling, frequency content, interstorey drift, plastic hinge deformation, ductility.Cet article présente les résultats d'une étude analytique sur les déformations non-linéaires et la réponse ductile de murs de refend couplés (« coupled shear walls », CSWs) ductiles en béton armé sous des charges sismiques. Les CSWs sont conçus, calculés et détaillés en respectant le Code national du bâtiment du Canada (CNBC) de 1995 et les Normes canadiennes sur le béton CAN3-A23.3-94. Les paramètres et hypothèses de l'étude de même que la description des modèles et de la procédure sont décrits ailleurs de façon détaillée. Les résultats indiquent que le mouvement maximal inter-étages provenant des analyses dynamiques est bien en-deça de celui obtenu à partir des analyses statiques avec les forces latérales spécifiées par le CNBC. Il a aussi été trouvé qu'il est subtantiellement plus bas pour des CSWs élevés comparés à des CSWs délévation moyenne à basse, et décroît légèrement seulement lorsque le degré de couplage s'accroît à l'intérieur de l'intervalle considéré dans cette étude. Il a aussi été le plus grand pour des enregistrements sismiques avec des rapports PGA/PGV bas. Les rotations plastiques à la rotule de même que les rotations plastiques à la rotule accumulées, en général, diminuent lorsque le nombre d'étages augmente. Le facteur de ductilité en déplacement maximal reste sous la valeur de 4,0 specifiée par le CNBC pour des CSWs ductiles. L'influence du degré de couplage sur le facteur de ductilité en déplacement ductile maximale a été trouvé comme étant négligible. Aussi, le facteur de ductilité en déplacement maximal décroît lorsque lorsque le nombre d'étages s'accroît. Le facteur de ductilité rotationnelle maximal dans le couplage des poutres décroît lorsque le nombre d'étages s'accroît, et a été en géneral moindre que la limite pratique acceptée de 10, sauf pour quelques CSWs courts.Mots clés : murs de refend, béton armé, sismique, degrée de couplage, contenu de fréquence, mouvement inter-étages, déformation plastique à la rotule, ductile.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]