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.

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.

Shear strength of members without transverse reinforcement

1996 ◽  
Vol 23 (1) ◽  
pp. 30-41 ◽  
Author(s):  
Perry Adebar ◽  
Michael P. Collins
Keyword(s):  
Shear Strength ◽  
Design Method ◽  
Bending Moment ◽  
American Concrete Institute ◽  
Shear Capacity ◽  
Transverse Reinforcement ◽  
Theory Approach ◽  
Shear Design ◽  
Truss Model ◽  
Variable Angle

The variable angle truss model is extended to members without transverse reinforcement by introducing concrete tension ties perpendicular to concrete compression struts. The modified compression field theory approach of limiting the shear transfer across diagonal cracks is combined with the variable angle truss model to develop equations for the shear capacity of members without transverse reinforcement. These equations are the theoretical basis of tabulated values for members without stirrups in the general shear design method of the 1994 Canadian concrete code. This paper also presents the results from an experimental study in which 27 narrow (beam-like) wall elements, with significant longitudinal reinforcement and little or no transverse reinforcement, were subjected to combined axial tension, bending moment, and shear. The experimental results are compared with predictions from the 1994 Canadian concrete code, as well as the American Concrete Institute building code. Key words: building codes, reinforced concrete, shear strength, structural design, tension, tests, truss model.

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.

scholarly journals Shear Performance of Optimized-Section Precast Slab with Tapered Cross Section

2018 ◽  
Vol 11 (1) ◽  
pp. 163 ◽  
Author(s):  
Hyunjin Ju ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hae-Chang Cho ◽  
Kang Kim ◽  
...  
Keyword(s):  
Cross Section ◽  
Design Method ◽  
Precast Concrete ◽  
Bending Moment ◽  
Shear Behaviour ◽  
Element Analysis ◽  
Cross Sectional ◽  
Shear Design ◽  
Shear Performance ◽  
And Performance

The optimized-section precast slab (OPS) is a half precast concrete (PC) slab that highlights structural aesthetics while reducing the quantity of materials by means of an efficient cross-sectional configuration considering the distribution of a bending moment. However, since a tapered cross section where the locations of the top and bottom flanges change is formed at the end of the member, stress concentration occurs near the tapered cross section because of the shear force and thus the surrounding region of the tapered cross section may become unintentionally vulnerable. Therefore, in this study, experimental and numerical research was carried out to examine the shear behaviour characteristics and performance of the OPS with a tapered cross section. Shear tests were conducted on a total of eight OPS specimens, with the inclination angle of the tapered cross section, the presence of topping concrete and the amount of shear reinforcement as the main test variables and a reasonable shear-design method for the OPS members was proposed by means of a detailed analysis based on design code and finite-element analysis.

Dynamic Shear Resistance of RC Beams Based on Modified Compression Field Theory

2016 ◽  
Vol 711 ◽  
pp. 799-805
Author(s):  
Kazunori Fujikake ◽  
Amornthep Somraj
Keyword(s):  
Field Theory ◽  
Analytical Model ◽  
Shear Capacity ◽  
Experimental Results ◽  
Rc Beams ◽  
Dynamic Shear ◽  
Loading Tests ◽  
Blast Loadings ◽  
Modified Compression Field Theory ◽  
Compression Field

The aim of this study was to develop an analytical model to estimate the dynamic shear capacity of RC beams which may exhibit diagonal tension failure under impact and blast loadings. Thus, the modified compression field theory has been extended to dynamic loading in this study. The developed analytical model has been applied to the experimental results obtained from rapid loading tests of RC beams. As a result, the developed analytical model has been in good agreement with the experimental results.

scholarly journals Analysis of the Shear Capacity of Ultrahigh Performance Concrete Beams Based on the Modified Compression Field Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wei Feng ◽  
Hongming Feng ◽  
Zhijun Zhou ◽  
Xiongwei Shi
Keyword(s):  
Field Theory ◽  
Failure Modes ◽  
Shear Capacity ◽  
Analysis Model ◽  
Shear Span ◽  
Compression Failure ◽  
Shear Bearing Capacity ◽  
Modified Compression Field Theory ◽  
Compression Field ◽  
Simplified Formula

An analysis model of the shear capacity of prestressed ultrahigh performance concrete (UHPC) beams under the combined action of bending and shearing was established in this paper based on the modified compression field theory and by considering the unique material constitutive relation of UHPC. Shear tests were performed using three prestressed UHPC-T beams with different shear-span ratios to verify the correctness of the model. The results showed that the shear-span ratio greatly influenced the shear capacity and failure modes of UHPC-T beams. Upon increasing the shear-span ratio, the failure modes of the three beams were inclined compression failure, shear compression failure, and diagonal tension failure, successively. When the shear-span ratio changed from 1.04 to 2.12, the shear bearing capacity decreased greatly; however, when the shear-span ratio changed from 2.12 to 3.19, the decrease of the shear bearing capacity was very small. In addition, the MCFT analysis model was used to analyze the experimental data, and the predicted results were in good agreement, which proved the applicability of the model. Finally, according to the existing shear test results of UHPC beams and based on the main influencing factors, a simplified formula for predicting the shear capacity of UHPC beams was obtained by fitting. Comparing the MCFT model with the results of other pieces of literature, this formula accurately predicted the shear capacity of UHPC beams. The MCFT model and the simplified formula presented in this paper provide a powerful tool for predicting the shear performance of UHPC-T beams, which will contribute to the design and analysis of UHPC-T beams.

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