Seismic force demand on ductile reinforced concrete shear walls subjected to western North American ground motions: Part 2 — new capacity design methods

2012 ◽  
Vol 39 (7) ◽  
pp. 738-750 ◽  
Author(s):  
Yannick Boivin ◽  
Patrick Paultre
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Ground Motions ◽  
Plastic Hinge ◽  
Shear Walls ◽  
Companion Paper ◽  
Design Methods ◽  
Design Codes ◽  
Capacity Design ◽  
Seismic Force

This paper proposes for the Canadian Standards Association (CSA) standard A23.3 new capacity design methods, accounting for higher mode amplification effects, for determining, for a single plastic hinge design, capacity design envelopes for flexural and shear strength design of regular ductile reinforced concrete cantilever walls used as seismic force resisting system for multistorey buildings. The derivation of these methods is based on the outcomes from a review on various capacity design methods proposed in the current literature and recommended by design codes and from the extensive parametric study presented in the companion paper. A discussion on the limitations of the proposed methods and on their applicability to various wall systems is presented.

Seismic force demand on ductile reinforced concrete shear walls subjected to western North American ground motions: Part 1 — parametric study

2012 ◽  
Vol 39 (7) ◽  
pp. 723-737 ◽  
Author(s):  
Yannick Boivin ◽  
Patrick Paultre
Keyword(s):  
Reinforced Concrete ◽  
Parametric Study ◽  
Plastic Hinge ◽  
Time History ◽  
Shear Walls ◽  
Beam Model ◽  
Site Class ◽  
Seismic Force ◽  
Inelastic Shear ◽  
Axial Interaction

A parametric study of regular ductile reinforced concrete (RC) cantilever walls designed with the 2010 National building code of Canada and the 2004 Canadian Standards Association (CSA) standard A23.3 for Vancouver is performed to investigate the influence of the following parameters on the higher mode amplification effects, and hence on the seismic force demand: number of storeys, fundamental lateral period (T), site class, wall aspect ratio, wall cross-section, and wall base flexural overstrength (γw). The study is based on inelastic time-history analyses performed with a multilayer beam model and a smeared membrane model accounting for inelastic shear–flexure–axial interaction. The main conclusions are that (i) T and γware the studied parameters affecting the most dynamic shear amplification and seismic force demand, (ii) the 2004 CSA standard A23.3 capacity design methods are inadequate, and (iii) a single plastic hinge design may be inadequate and unsafe for regular ductile RC walls with γw < 2.0.

Seismic Collapse Fragility Analysis of Reinforced Concrete Shear Wall Buildings

2019 ◽  
Vol 35 (1) ◽  
pp. 383-404 ◽  
Author(s):  
Mayssa Dabaghi ◽  
George Saad ◽  
Naser Allhassania
Keyword(s):  
Reinforced Concrete ◽  
Line Element ◽  
Ground Motions ◽  
Shear Walls ◽  
Element Model ◽  
Shear Wall ◽  
Capacity Design ◽  
Building Models ◽  
Seismic Collapse ◽  
Dynamic Amplification

This paper examines the behavior of reinforced concrete shear wall buildings subjected to strong earthquake ground motions, with a focus on collapse performance. The effect of varying the number of stories, shear wall and boundary element dimensions, and reinforcement detailing on the seismic collapse fragility is investigated. The buildings are seismically designed based on the ASCE 7-10 and ACI 318-14 codes with additional provisions for capacity design and dynamic amplification. The shear walls are modeled using the shear-flexure interaction multiple vertical line element model with nonlinear hysteretic material models. Incremental dynamic analysis is performed to simulate the structural collapse of the two-dimensional building models subjected to the FEMA-P695 set of far field recorded ground motions scaled to increasing intensity values. For each building, a lognormal collapse fragility curve is fitted to the results. A collapse assessment of the studied buildings shows how the seismic performance is significantly affected by the varied parameters.

scholarly journals The shear strength of shear walls

1970 ◽  
Vol 3 (4) ◽  
pp. 148-162
Author(s):  
T. Paulay
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Walls ◽  
Shear Wall ◽  
Reinforced Concrete Beams ◽  
Research Projects ◽  
Deep Beams ◽  
Current Recommendation ◽  
The University

To enable a comparison between the shear strength of shear walls and that of reinforced concrete beams to be made, the behaviour of the latter is briefly reviewed. The findings of research projects, related to deep beams and the effects of repeated cyclic loading, are summarised. More detailed information on the shear strength of deep beams, tested at the University of Canterbury, is presented, Particular problems associated with four classes of typical shear walls of multi-storey structures are briefly highlighted. The current recommendation of the
 SEAOC code, as applied to shear walls, are critically examined and certain
anomalies, which may ensue from their interpretation, are illustrated. Areas of research, related to the full evaluation of reinforced concrete shear wall
 behaviour, are suggested. The paper concludes with a number of design recommendations which suggest themselves from this review.

Two-discrete-elements concrete shear deformation model: Formulation and application in the seismic evaluation of reinforced concrete shear walls

2020 ◽  
Vol 23 (16) ◽  
pp. 3429-3445
Author(s):  
Fadi Oudah ◽  
Raafat El-Hacha
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Deformation ◽  
Axial Load ◽  
Shear Deformation Theory ◽  
Shear Walls ◽  
Shear Capacity ◽  
Complex Nature ◽  
Deformation Model ◽  
Discrete Elements

Shear deformation in reinforced concrete structures is of a complex nature. A thorough understanding of the interaction between the shear strength, flexural strength, and flexural ductility is not yet achieved. A new shear-deformation-based theory is proposed and validated in this study. The so-called two-discrete-elements (TDE) shear deformation theory idealizes reinforced concrete members as series of two discrete types of elements: S-elements and C-elements. The S-elements are used to model the regions of concrete reinforced to resist flexural and shear deformation using longitudinal and transverse steel reinforcement, while the C-elements are used to model the reinforced concrete sections bounded by the stirrups. The compatibility between the two types of elements is enforced by controlling the crack angle. The formulation of the newly developed theory is discussed in terms of equilibrium of forces, compatibility within the elements, compatibility at the interface, and constitutive material modeling. The theory was applied to evaluate the deformability of reinforced concrete shear walls subjected to lateral loads for seismic design applications. It was also implemented to generate sample design charts referred to as axial–moment–shear interaction diagrams. These diagrams can be used to design shear walls subjected to combined action of axial load, moment, and shear as opposed to the conventional interaction diagrams in which only the axial load versus moment relationship is considered. Analysis results indicated the adequacy of the proposed theory in capturing the shear strength degradation and predicting structural failures controlled by the shear capacity.

scholarly journals Shear Strength of Reinforced Concrete Columns Retrofitted by Glass Fiber Reinforced Polyurea

2020 ◽  
Vol 6 (10) ◽  
pp. 1852-1863
Author(s):  
Jun-Hyeok Song ◽  
Eun-Taik Lee ◽  
Hee-Chang Eun
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Glass Fiber ◽  
Plastic Hinge ◽  
Compressive Load ◽  
Shear Capacity ◽  
Dissipated Energy ◽  
Fiber Reinforced ◽  
Lateral Confinement ◽  
Glass Fiber Reinforced

Aged structures and structures constructed based on outdated non-seismic design codes should be retrofitted to enhance their strength, ductility, and durability. This study evaluates the structural performance of reinforced concrete (RC) columns enhanced via polyurea or glass fiber reinforced polyurea (GFRPU) strengthening. Four RC column specimens, including a reference specimen (an unstrengthened column), were tested to evaluate the parameters of the strengthening materials and the strengthened area. The tests were carried out under a combined constant axial compressive load and quasi-static cyclic loading. The experimental results show that the composite strengthening provides lateral confinement to the columns and leads to enhanced ductility, shear-resistance capacity, and dissipated energy. The shear strength provided by the composites depends on the degree of lateral confinement achieved by the composite coating. The specimens finally failed through the development of diagonal tension cracks within the potential plastic hinge regions. The specimen treated with GFRPU strengthening showed greater strength and dissipated more energy than the specimen treated with polyurea strengthening. Furthermore, by modifying ATC-40, this study proposed an equation to estimate the shear capacity provided by the composites.

SHEAR MECHANISM AND SHEAR STRENGTH PREDICTION OF REINFORCED CONCRETE T-BEAMS

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noridah Mohamad ◽  
Mohammed Anwar Hail al-Qershi ◽  
J. Jayaprakash ◽  
Priyan Mendis
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Shear Behaviour ◽  
Design Codes ◽  
Shear Mechanism ◽  
Strength Capacity

Shear failure in reinforced concrete beams are sudden failures and should be avoided at all times. However, the shear behaviour of a reinforced concrete beam is a complex mechanism and requires in-depth study. To understand the shear mechanism, two (2) simply supported reinforced concrete T-beams, BEAM1 and BEAM2 were tested until failure subjected to a 4-point bending test. Both beams were designed to the recommendations and specifications of two (2) established design codes by ACI318-08 and Eurocode2 (EC2). The study comprises of two reinforced concrete T-beams having similar variables and parameters with longitudinal reinforcement of ρ = 2.15% and shear span-to-effective depth ratio (av/d) of 3.5. Shear reinforcement or stirrups has been added to the specimen and its spacing of stirrups has been provided with the provisions of the codes. The findings from the study indicate that ACI318-08 and EC2 design codes shows significant differences in determining its shear strength capacity Vn and concrete shear resistance Vcof the T-beams. However, both results were less conservative in its prediction when compared to the experimental results. 

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