scholarly journals Nonlinear Analysis of Reinforced Concrete Shear Walls Using Nonlinear Layered Shell Approach

2021 ◽  
Vol 65 (2) ◽  
pp. 63-79
Author(s):  
Ali Vatanshenas
Keyword(s):  
Reinforced Concrete ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Element Model ◽  
Computational Effort ◽  
Nonlinear Static Analysis ◽  
Analytical Models ◽  
Layered Shell ◽  
Concrete Wall ◽  
Cracking Pattern

Abstract This study discusses nonlinear modelling of a reinforced concrete wall utilizing the nonlinear layered shell approach. Rebar, unconfined and confined concrete behaviours are defined nonlinearly using proposed analytical models in the literature. Then, finite element model is validated using experimental results. It is shown that the nonlinear layered shell approach is capable of estimating wall response (i.e., stiffness, ultimate strength, and cracking pattern) with adequate accuracy and low computational effort. Modal analysis is conducted to evaluate the inherent characteristics of the wall to choose a logical loading pattern for the nonlinear static analysis. Moreover, pushover analysis’ outputs are interpreted comprehensibly from cracking of the concrete until reaching the rupture step by step.

Pushover Analysis Based on Equivalent Diagonal Springs for the Assessment of the Seismic Safety of Post-and-Beam Timber Buildings Braced with Nailed Shear Walls

2017 ◽  
Vol 755 ◽  
pp. 170-180
Author(s):  
Natalino Gattesco ◽  
Ingrid Boem
Keyword(s):  
Static Analysis ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Nonlinear Static Analysis ◽  
Plastic Behavior ◽  
Ground Acceleration ◽  
Good Reliability ◽  
Equivalent Viscous Damping ◽  
Seismic Safety ◽  
Capacity Spectrum

A method for a simplified modeling of post-and-beam timber buildings braced with nailed shear walls, useful for seismic design purposes, is presented and discussed in the paper. This strategy is based on the schematization of the vertical diaphragms through equivalent diagonal springs with elastic-plastic behavior and allows the assessment of the resisting ground acceleration by performing nonlinear static analysis; the Capacity Spectrum method based on equivalent viscous damping was applied. This nonlinear procedure constitutes a reliable and simple alternative to the linear static analysis using the behavior factor q. The procedures to determine the characteristics of the equivalent elements (stiffness and load-carrying capacity) are based on analytical evaluations, starting from the actual characteristic of shear walls. A comparison between the results of numerical simulation based of more refined and complex models, previously presented by the authors, and this time-reducing, simplified analysis proved the good reliability of the method.

Spectrum-based pushover analysis for the quick seismic demand estimation of reinforced concrete shear walls

Structures ◽  
2020 ◽  
Vol 27 ◽  
pp. 1490-1500
Author(s):  
Yang Liu ◽  
J.S. Kuang ◽  
Qunxian Huang ◽  
Zixiong Guo ◽  
Xueying Wang
Keyword(s):  
Reinforced Concrete ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Demand Estimation ◽  
Seismic Demand

Seismic Analysis of Confined Masonry Shear Walls Using the Wide Column Model

2016 ◽  
Vol 857 ◽  
pp. 212-218
Author(s):  
Kiran Rangwani ◽  
Svetlana Brzev
Keyword(s):  
Reinforced Concrete ◽  
Latin American ◽  
Seismic Analysis ◽  
Shear Walls ◽  
Computational Effort ◽  
Wall Structure ◽  
Confined Masonry ◽  
Column Model ◽  
Wall Stiffness ◽  
Lateral Displacements

Confined Masonry (CM) structural system consists of masonry walls enclosed by reinforced concrete (RC) confining elements (tie-columns and tie-beams) and is usually supported by reinforced concrete floors and roof. This technology has been widely used for construction of low-and medium-rise buildings in Latin America, Europe, South Asia, and Middle East, and it has a proven record of good performance in damaging earthquakes. CM construction is not currently practiced in India and is not addressed by Indian design codes. Seismic analysis of CM wall panels can be performed using Wide Column Model (WCM), also known as Equivalent Frame Model. WCM is a macro model where a wall structure and the supporting floors and roof are idealized as a bare frame. CM walls can be modelled as wide columns with transformed section properties accounting for composite action of masonry and RC tie-columns. Beams in these bare frames have rigid segments simulating the effect of wall stiffness, and flexible segments that simulate the effect of floor and roof slabs. WCM has been recognized as a viable model for seismic analysis of CM buildings in Latin American countries, however this model is not well known in India. The results presented in this paper are based on linear elastic analyses of typical multi-storey CM solid walls and walls with openings. The output parameters include shear forces, bending moments, stiffness, and lateral displacements. A comparison of the results obtained using the WCM and the Finite Element Method (FEM) has been presented. WCM can be useful for seismic analysis of CM buildings since it does not require significant computational effort and can be applied using a variety of software packages.

scholarly journals Global Retrofitting Strategies for an Existing Three-storied RC School Building in Mandalay, Myanmar

2020 ◽  
Vol 37 (2) ◽  
Author(s):  
Thiri Thwe ◽  
Nang Su Le′ Mya Thwin ◽  
Ne Min Hein
Keyword(s):  
Reinforced Concrete ◽  
Steel Plate ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Earthquake Hazard ◽  
Vulnerability Index ◽  
Seismic Zone ◽  
Index Method ◽  
Steel Plate Shear Walls ◽  
Existing Building

Low to severe earthquakes occur around the world every year, damaging and causing structural failure in buildings. Consequently, seismic improvements are required for existing buildings that are vulnerable to damage by seismic forces. The objective of this study was to investigate retrofitting strategies in terms of their sustainability. Mandalay, Myanmar, was selected as the study area as it is located near the Sagaing fault, which itself is in a strong earthquake zone (seismic zone 4). A three-storied RC building with a non-seismic design was selected as a case study building. An investigation was carried out into the performance and vulnerability of the building under three earthquake hazard levels. The vulnerability index value was calculated using the Priority Index method. Meanwhile, non-linear static pushover analysis was performed to investigate the performance of the existing building using SAP2000 V14 software. Four different types of retrofitting strategies were considered, namely reinforced concrete shear walls with openings, reinforced concrete shear walls without openings, steel plate shear walls, and finally steel bracing. Among these, it was found that the use of steel plate shear walls was the best retrofitting technique, owing to it having the best performance along with the lowest displacement. Its performance level reached up to the Immediate Occupancy (IO) level even under the conditions of a Maximum Consider Earthquake (MCE).

scholarly journals Jacketing of existing reinforced concrete structures with composites in view of seismic rehabilitation

2018 ◽  
Vol 191 ◽  
pp. 00006
Author(s):  
Siham Bouras ◽  
Abdellatif Khamlichi ◽  
Sabri Attajkani
Keyword(s):  
Reinforced Concrete ◽  
Pushover Analysis ◽  
Nonlinear Static Analysis ◽  
Initial State ◽  
Seismic Rehabilitation ◽  
Lateral Resistance ◽  
Concrete Building ◽  
Nonlinear Static ◽  
Static Pushover Analysis

Seismic rehabilitation of pre-code existing buildings requires the choice of the method of strengthening and the determination of the amount of materials to be used optimally. Accurate evaluation of the building response in terms of its capacity at the initial state and that obtained after application of some reinforcement should be performed. For regular buildings, the nonlinear static analysis procedure constitutes a powerful tool that is used to estimate seismic performance. This procedure is characterised by its high effectiveness to account for the non-linear characteristics of the materials involved and provides a direct mean to shape the capacity curve of the construction; enabling then to make the correct decision about rehabilitation task with regards to a desired performance state. In this work, the nonlinear static pushover analysis was performed by means of ZeusNL software. Use was made of the Moroccan seismic regulations RPS2000 version 2011to determine the targeted seismic demand. Considering a four floor reinforced concrete building which is undersized with regards to actual seismic regulation, jacketing with fiber reinforced composites at different reinforcement rates was analyzed. The obtained results were expressed in terms of the lateral resistance capacity and the building tip displacement. Optimal jacketing of columns was then determined.

A regularized fiber element model for reinforced concrete shear walls

2016 ◽  
Vol 45 (13) ◽  
pp. 2063-2083 ◽  
Author(s):  
Jorge A. Vásquez ◽  
Juan C. de la Llera ◽  
Matías A. Hube
Keyword(s):  
Reinforced Concrete ◽  
Shear Walls ◽  
Element Model ◽  
Fiber Element

scholarly journals Seismic Fragility of Ordinary Reinforced Concrete Shear Walls with Coupling Beams Designed Using a Performance-Based Procedure

2020 ◽  
Vol 10 (12) ◽  
pp. 4075
Author(s):  
Seong-Ha Jeon ◽  
Ji-Hun Park
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Seismic Design ◽  
Nonlinear Dynamic ◽  
Shear Force ◽  
Nonlinear Dynamic Analysis ◽  
Shear Walls ◽  
Analytical Models ◽  
High Rise ◽  
Collapse Probability

The seismic performance of ordinary reinforced concrete shear walls, that are commonly used in high-rise residential buildings in Korea (h < 60 m), but are prohibited for tall buildings (h ≥ 60 m), is evaluated in this research project within the framework of collapse probability. Three bidimensional analytical models comprised of both coupled and uncoupled shear walls exceeding 60 m in height were designed using nonlinear dynamic analysis in accordance with Korean performance-based seismic design guidelines. Seismic design based on nonlinear dynamic analysis was performed using different shear force amplification factors in order to determine an appropriate factor. Then, an incremental dynamic analysis was performed to evaluate collapse fragility in accordance with the (Federal Emergency Management Agency) FEMA P695 procedure. Four engineering demand parameters including inter-story drift, plastic hinge rotation angle, concrete compressive strain and shear force were introduced to investigate the collapse probability of the designed analytical models. For all analytical models, flexural failure was the primary failure mode but shear force amplification factors played an important role in order to meet the requirement on collapse probability. High-rise ordinary reinforced concrete shear walls designed using seven pairs of ground motion components and a shear force amplification factor ≥ 1.2 were adequate to satisfy the criteria on collapse probability and the collapse margin ratio prescribed in FEMA P695.

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 Response Reduction Factor for SMRF 3D Frame Buildings on Sloppy Ground

2020 ◽  
Vol 9 (4) ◽  
pp. 2085-2092
Keyword(s):  
Control Method ◽  
Pushover Analysis ◽  
Research Work ◽  
Regular Structure ◽  
Reduction Factor ◽  
Nonlinear Static Analysis ◽  
Analytical Models ◽  
Analysis And Design ◽  
Response Reduction Factor ◽  
Finite Element Software

Lateral forces are key factors in the design of building structure and in general these forces are evaluated using linear static method with the incorporation of response reduction factor. The actual intensity of lateral force is minimized by response reduction factor. However IS Code 1893:2016 does not give information about the components of response reduction factor. The value mentioned in IS code may be based on expert engineering judgment without any scientific basis. The Present research work focus on the estimation of response reduction factor (R) of SMRF frames considering slope terrain without any impairment in slope in Zone V. Fifteen frame models are prepared according to the guideline of IS Code 456:2000 and lateral load on frame was assigned as per IS 1893:2016 (Part-1) for the research purposes. Evaluation of response Reduction Factor according to Applied Technical Council (ATC-19) is carried out which stated that response reduction factor is the product of Strength factor, Redundancy factor and Ductility factor. Pushover analysis also termed as nonlinear static analysis under displacement control method is performed on the analytical models by an integrated finite element software for structural analysis and design called ETABS 2017. P-delta governs the geometrical non-linearity of structure. It has been observed over strength of regular structure is more as compared to irregular geometrical model whereas the ductility reduction factor does not show any significant trend. Moreover, all the models are limited in 6 story only with same structural property additional research is needed considering wider set of parameters framework.

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