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 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.

Inelastic seismic shear amplification due to higher mode effects in reinforced concrete coupled walls

2021 ◽  
pp. 875529302110533
Author(s):  
Gabriel Rivard ◽  
Steeve Ambroise ◽  
Patrick Paultre
Keyword(s):  
Reinforced Concrete ◽  
Parametric Study ◽  
Numerical Study ◽  
Plastic Hinge ◽  
Experimental Studies ◽  
Physical Parameters ◽  
Intensity Level ◽  
Shear Forces ◽  
Coupled Walls ◽  
Seismic Shear

Recent numerical and experimental studies on reinforced concrete shear walls and coupled walls have shown shear forces greater than expected when the walls are subjected to earthquakes at an intensity level that does not exceed the design values. This amplification of shear forces is attributable to the effects of higher modes after the walls develop a plastic hinge at the base. These effects have been recently recognized in North American design codes for cantilever walls and is currently neglected in the design of ductile coupled walls. As part of the research program described in this article, a parametric study was carried out on coupled wall systems to identify the geometric and physical parameters having the greatest influence on the seismic shear amplification. Using the results of this parametric study, an extensive numerical study was conducted on classes of ductile coupled walls subjected to seismic excitation representative of Western and Eastern Canada. This extensive study led to the establishment of shear amplification prediction equations for use in building codes.

scholarly journals Analysis and design of a base-isolated reinforced concrete frame building

1978 ◽  
Vol 11 (4) ◽  
pp. 245-254 ◽  
Author(s):  
L. M. Megget
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Time History ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Elastomeric Bearings ◽  
Analysis And Design ◽  
Concrete Frame ◽  
Frame Building ◽  
Reinforced Concrete Frame Structure

The paper describes the dynamic and static analyses and design of a four storey ductile reinforced concrete frame structure isolated from the foundations by elastomeric bearings incorporating lead energy dampers. Results from inelastic, time-history analyses for the isolated and non-isolated structure are compared for several input earthquake motions. The benefits of energy dampers in reducing the isolated building's response (shears, plastic hinge demands and interstorey drifts) are detailed. Differences from conventional ductile design and detailing as well as design recommendations are included.

scholarly journals Seismic Response of the Three-Span Bridge with Innovative Materials Including Fault-Rupture Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Jiping Ge ◽  
M. Saiid Saiidi
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Ground Displacement ◽  
Finite Element Software ◽  
Near Fault ◽  
Residual Displacements ◽  
Parallel Direction

The seismic performance of the SR99 Bridge with conventional and advanced details in Seattle, Washington, was studied via a nonlinear, time history analysis of a multidegree of freedom model. The bridge consists of three spans supported on two single-column piers and will be the first built bridge in the world in which superelastic shape memory alloy (SMA) and engineered cementitious composite (ECC) are implemented to reduce damage at plastic hinges and minimize residual displacements. Existing finite-element formulations in the finite-element software OpenSees are used to capture the response of the advanced materials used in the bridge. The earthquake induced by strike-slip fault was assumed to produce a surface rupture across the SR99 Bridge. The effect of the rupture was modeled by a static, differential ground displacement in the fault-parallel direction across the rupture. The synthetic suite of scaled bidirectional near-fault ground motions used in the analysis contains common near-fault features including a directivity pulse in the fault-normal direction and a fling step in the fault-parallel direction. Comparisons are made on behavior of two different bridge types. The first is a conventional reinforced concrete bridge and the second is a bridge with Nickel-Titanium (NiTi) SMA reinforcing bar at the plastic hinge zone and ECC in the whole column. Fault-parallel near-fault earthquakes typically exhibit a static permanent ground displacement caused by the relative movement of the two sides of the fault. When the fault is located between piers, the pier shows a higher demand. Fault-normal analysis results show effectiveness of the innovative interventions on the bridges in providing excellent recentering capabilities with minimal damage to the columns. But the maximum drift computed in the SMA bridge is slightly higher than reinforced concrete (RC) bridges, contributed by comparatively low stiffness of the superelastic SMA bars compared to the steel reinforcing bars.

Inelastic analysis of a reinforced concrete shear wall building according to the National Building Code of Canada 2005

2006 ◽  
Vol 33 (7) ◽  
pp. 854-871 ◽  
Author(s):  
M Panneton ◽  
P Léger ◽  
R Tremblay
Keyword(s):  
Reinforced Concrete ◽  
Three Dimensional ◽  
Time History ◽  
Shear Walls ◽  
Shear Wall ◽  
Fundamental Period ◽  
Building Code ◽  
Base Shear ◽  
Inelastic Analysis ◽  
The Impact

An eight-storey reinforced concrete shear wall building located in Montréal and designed according to the 1995 National Building Code of Canada (NBCC) and the Canadian Standards Association standard CSA-A23.3-94 is studied to evaluate the impact of new requirements for inclusion in new editions of the NBCC and CSA-A23.3. Static and modal analyses were conducted according to the 2005 NBCC (draft 2003) and CSA-A23.3-04 (draft 4) procedures, and three-dimensional dynamic inelastic time history analysis was performed using three earthquake records. The building is braced by four flat shear walls and three cores. Various estimates of the fundamental period of vibration based on empirical expressions presented in the literature or structural models with different stiffness assumptions were examined. The analysis also permitted the study of the displacement and force demand on the lateral load resisting system. It was found that the base shear from the 2005 NBCC is 29% higher than the 1995 NBCC value when code empirical formulae are used for the fundamental period of vibration.Key words: building, shear wall, inelastic seismic response, NBCC, CSA-A23.3 design of concrete structures.

Seismic demand of moderately ductile reinforced concrete shear walls subjected to high-frequency ground motions

2014 ◽  
Vol 41 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Hieu Luu ◽  
Pierre Léger ◽  
Robert Tremblay
Keyword(s):  
Reinforced Concrete ◽  
High Frequency ◽  
Shear Force ◽  
Shaking Table Test ◽  
Numerical Models ◽  
Response Spectrum ◽  
Shear Walls ◽  
Shaking Table ◽  
Seismic Force ◽  
Code Provisions

A parametric study was performed to examine the seismic behaviour of moderately ductile (MD) reinforced concrete shear walls designed according to Canadian code provisions, including National Building Code of Canada (NBCC) 2010 and Canadian Standards Association (CSA) 23.3-04, when subjected to typical high-frequency eastern North America earthquakes. The numerical models were experimentally validated based on large specimens shaking table test results. The results obtained following the code response spectrum procedure were compared with the results from inelastic response history analyses to investigate the effect of higher modes on seismic force demands. The results indicate that current code provisions for MD shear walls need to be modified. A new base shear factor and shear force design envelop are proposed to evaluate the seismic shear force demand more realistically. This study also recommends that the current CSA 23.3-04 requirements for ductile shear walls for bending moments could be applied to constrain the location of inelastic flexural deformations at the base of MD shear walls.

scholarly journals Evaluation of elastic stiffness factor of 2D reinforced concrete frame system with different parameters

2021 ◽  
Vol 2 (2) ◽  
pp. 26-31
Author(s):  
Omar Ahmad
Keyword(s):  
Reinforced Concrete ◽  
Lateral Displacement ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Elastic Stiffness ◽  
Span Length ◽  
Base Shear ◽  
Reinforced Concrete Frame ◽  
Plastic Hinges

In general, the buildings are designed based on the applied loads on them, and these buildings generally have elastic structural behaviour. However, these structures may be subjected to unexpectedly strong seismic forces that exceed their elastic limits. In order to find the rigidity and load-bearing trend of the building without the formation of plastic hinges and failure, pushover analysis should be performed. Pushover analysis is a non-linear static analysis in which the structure is subjected to lateral loads, so some parameters are recorded, such as failure, formation of plastic hinges, and yield. The elastic stiffness factor is the ability of a building to bear the loads on it before the failure and existent of the plastic hinges. In this study, pushover analysis had been done on 12 two-dimensional reinforced concrete frames with a different number of stories, different span lengths and with or without shear walls to find the effect of the span length, shear wall and the number of stories on the elastic stiffness factor. After performing the pushover analysis, the elastic stiffness factor had been evaluated from the pushover curve by dividing the base shear over the lateral displacement at the first point of the occurrence of the plastic hinge. The results obtained from the study showed that the elastic stiffness factor increases with the increase of the span length, while it decreases with the increase of the number of stories. As well, the frames with shear walls are stiffer than the frames without shear walls.

scholarly journals EFFECTS OF SHEAR WALLS ON A TYPICAL FOUR-STORY REINFORCED CONCRETE STRUCTURE SUBJECTED TO SEVERE EARTHQUAKE EVENTS

2021 ◽  
Vol 30 (4) ◽  
pp. 779-795
Author(s):  
Nader Zad ◽  
Hani Melhem
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Concrete Structure ◽  
Time History ◽  
Shear Walls ◽  
Shear Stresses ◽  
Reinforced Concrete Structure ◽  
Beneficial Effects ◽  
Structural Resistance ◽  
Study Results

Various seismic-resistant design methods are used to ensure the stability of multi-story buildings against lateral forces caused by earthquakes. Utilization of reinforced concrete shear walls is one of the most reliable methods of design and construction of earthquake-resistant buildings because it increases structural resistance to lateral loads and stiffens and strengthens the structure, thereby minimizing earthquake-induced damages. This paper investigates the beneficial effects of using shear walls in the structural design of a typical low-rise building to improve its resistance to earthquake events. To this end, a four-story reinforced concrete structure is modeled first without shear walls, then with the addition to shear walls. The 2002 Denali Alaska earthquake is used as an example of a severe seismic excitation because it is considered the most massive strike-slip earthquake in North America in almost 150 year. SAP2000 is used to perform the dynamic analysis. In order to obtain an accurate representation of the structure’s behavior, response modal nonlinear time-history dynamic analysis is utilized to analyze and compare the response of the building with and without shear walls. Study results showed that shear walls are very effective in achieving compliance with seismic design codes. In addition, the use of shear walls significantly reduces the shear stresses, bending moments, and displacements of the various members of the structure.

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