Development of the 2004 Canadian Standards Association (CSA) A23.3 shear provisions for reinforced concrete

2006 ◽  
Vol 33 (5) ◽  
pp. 521-534 ◽  
Author(s):  
Evan C Bentz ◽  
Michael P Collins
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Structural Design ◽  
Design Method ◽  
Building Codes ◽  
Basic Assumptions ◽  
Shear Design ◽  
Shear Building ◽  
Simple Equations ◽  
General Method

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.Key words: shear, building codes, reinforced concrete, size effect, structural design.

Background to the general method of shear design in the 1994 CSA-A23.3 standard

1999 ◽  
Vol 26 (6) ◽  
pp. 827-839 ◽  
Author(s):  
Khaldoun N Rahal ◽  
Michael P Collins
Keyword(s):  
Prestressed Concrete ◽  
Structural Design ◽  
Design Method ◽  
Bending Moment ◽  
Shear Capacity ◽  
Shear Design ◽  
Standard Design ◽  
Modified Compression Field Theory ◽  
Compression Field ◽  
General Method

The 1994 CSA-A23.3 standard "Design of concrete structures" includes a new shear design method based on the equations of the modified compression field theory (MCFT). This "general method" is a simplification which casts the MCFT in the traditional "Vc + Vs" format resulting in a set of six general equations and two tables. This new method unifies the treatment of reinforced, partially prestressed and fully prestressed concrete and accounts, in a rational manner, for the effects of axial load and bending moment on shear capacity. Simplifying the MCFT while maintaining acceptable generality and accuracy involved a number of considerations and assumptions. This paper gives the background to the development of these shear design equations and tables of the general method.Key words: beams, building codes, crack width and spacing, diagonal cracking, reinforced concrete, shear strength, size effect in shear, structural design.

Einheitliches Querkraftmodell für Stahl- und Spannbetonbrücken – erweiterte Grundlagen/Uniform Shear Design Method for Existing Reinforced and Prestressed Concrete Bridges – Extended Background

Bauingenieur ◽  
2016 ◽  
Vol 91 (12) ◽  
pp. 487-495
Author(s):  
Martin Herbrand ◽  
Martin Classen ◽  
Alexander Stark ◽  
Dominik Kueres
Keyword(s):  
Prestressed Concrete ◽  
Design Method ◽  
Concrete Bridges ◽  
Prestressed Concrete Bridges ◽  
Shear Design ◽  
Uniform Shear

Während das Biegetragverhalten von Stahl- und Spannbetonbauteilen als gelöst angesehen wird, ist das Querkrafttragverhalten schubschlanker Bauteile nicht abschließend geklärt. Vor allem für die Beurteilung von Bestandsbauwerken sind aber Querkraftmodelle notwendig, die möglichst einfach anwendbar sind und dennoch ausreichend genaue und damit wirtschaftliche Vorhersagen der Tragfähigkeit erlauben. Ein einheitliches Querkraftmodell mit Betontraganteil für Stahl- und Spannbetonbauteile ermöglicht bei der Bemessung einen stetigen Übergang zwischen Bauteilen ohne und mit Querkraftbewehrung, wenn deren Betontraganteile für asw = 0 identisch sind. Der Vergleich mit den ACI-DAfStb-Querkraftdatenbanken belegt, dass ein solches Modell für Bauteile mit Querkraftbewehrung zu deutlich geringeren Streuungen und gleichzeitig einem höheren Sicherheitsniveau im Vergleich zum aktuellen EC2 führt. Insbesondere für Bauteile mit geringen Querkraftbewehrungsgraden ergeben sich hierdurch höhere rechnerische Tragfähigkeiten, was zum Beispiel für die Nachrechnung von Bestandsbauwerken wie Brücken von Vorteil ist. In diesem Beitrag werden die Hintergründe für einen konsistenten Übergang von einen Fachwerkmodell mit Betontraganteil zu einem Fachwerkmodell mit variabler Druckstrebenneigung erläutert.

An evaluation of pile cap design methods in accordance with the Canadian design standard

2004 ◽  
Vol 31 (1) ◽  
pp. 109-119 ◽  
Author(s):  
William Cavers ◽  
Gordon A Fenton
Keyword(s):  
Reinforced Concrete ◽  
Structural Design ◽  
Design Methods ◽  
Building Codes ◽  
Design Models ◽  
Design Standard ◽  
Strut And Tie ◽  
Pile Cap ◽  
Pile Caps ◽  
Strut And Tie Model

There are a number of design methods that have been described for the design of pile caps, but there has been no consensus on which method provides the best approach for the working designer. This paper describes a study conducted to establish the performance of several pile cap design methods, particularly with respect to the Canadian standard, CSA A23.3-94. Previous research was examined to determine the basis of the design methods and the state of current research. The design methods identified were then applied to pile caps for which test data were available. The theoretical loads obtained using the various design methods were compared with the experimental loads. The results of this study indicate that two design models of the five examined are the most suitable. This study also indicates that the provisions of the Canadian design standard are adequate. A possible refinement of the strut-and-tie model incorporating a geometric limit is also outlined.Key words: building codes, footings, pile caps, reinforced concrete, structural design.

Does the shear strength of reinforced concrete beams and slabs depend upon the flexural reinforcement ratio or the reinforcement strain?

2013 ◽  
Vol 40 (11) ◽  
pp. 1068-1081 ◽  
Author(s):  
Mitra Noghreh Khaja ◽  
Edward G. Sherwood
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Shear Stresses ◽  
Shear Design ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
General Method

Beam tests are conducted to investigate the effect of the reinforcement ratio, ρ, and the shear span to depth ratio, a/d, on the shear strength of reinforced concrete beams and slabs without stirrups. The a/d ratio is shown to have a very significant effect on shear strength at both low values of a/d (where failure is governed by strut-and-tie mechanisms) and large values of a/d (where failure is governed by breakdown in beam action). Increases in ρ associated with increases in a/d such that the strain, or M/ρVd ratio, is kept constant will result in constant failure shear stresses. Shear design methods that do not account for a/d (e.g., ACI Committee 440) cannot predict the observed experimental behaviour, whereas the general method of the CSA A23.3 code can. Using the ACI 440 equation for Vc may reduce the economic competitiveness of fibre-reinforced polymer reinforcement versus steel reinforcement.

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