scholarly journals Stiffness-Displacement Correlation from the RC Shear Wall Tests of the SAFE Program: Derivation of a Capacity Line Model

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
Francisco J. Molina ◽  
Pierre Pegon ◽  
Pierre Labbé
Keyword(s):  
Normal Load ◽  
Response Spectrum ◽  
Oscillation Amplitude ◽  
Shear Walls ◽  
Logarithmic Scale ◽  
Visual Interpretation ◽  
Reinforcement Density ◽  
Safety Margins ◽  
Rc Shear Wall ◽  
Seismic Tests

The response of 13 reinforced concrete shear walls submitted to successive seismic tests has been postprocessed to produce time histories of secant stiffness and displacement oscillation amplitude. For every wall an envelope curve of displacement amplitude versus stiffness is identified which is fairly modelled by a straight line in double logarithmic scale. This relatively simple model, when used as a capacity line in combination with the demand response spectrum, is able to predict in an approximate manner the maximum response to the applied earthquakes. Moreover, the graphic representation of the demand spectrum and a unique model capacity line for a group of equal walls with different assumed design frequencies on them gives a visual interpretation of the different safety margins observed in the experiments for the respective walls. The same method allows as well constructing vulnerability curves for any design frequency or spectrum. Finally, the comparison of the different identified line models for the different walls allows us to assess the qualitative effect on the behaviour of parameters such as the reinforcement density or the added normal load.

scholarly journals The impact of shear wall location on the seismic response of RC frame buildings resting on sloping ground

2019 ◽  
Vol 2 (1) ◽  
pp. 61-68
Author(s):  
Upama Acharya ◽  
Jagat Kumar Shrestha
Keyword(s):  
Response Spectrum ◽  
Pushover Analysis ◽  
Structural Response ◽  
Earth Pressure ◽  
Shear Walls ◽  
Shear Wall ◽  
Sloping Ground ◽  
Negative Effect ◽  
Rc Shear Wall ◽  
The Impact

It is observed during the past earthquakes, buildings in hilly regions have experienced high degree of damage leading to collapse though they have been designed for safety of the occupants against natural hazards. Hence, while adopting practice of multistory buildings in these hilly and seismically active areas, utmost care should be taken for making these buildings earthquake resistant. For the buildings on sloping ground, the height of columns below plinth level is not same which affects the performance of building during earthquake. Hence to improve the seismic performance of building shear walls play very important role.It is very necessary to determine the most effective location of shear walls. Shear wall arrangement must be accurate, because if not, it will cause negative effect instead. This paper is aimed at predicting the effect of positioning RC shear wall of different shape on the structural response of RC building resting on sloping ground. Eight models have been prepared considering earth pressure and without considering earth pressure. The displacement of building is to be determined by nonlinear static pushover analysis. For the purpose of pushover analysis and response spectrum analysis finite element-based software SAP 2000 has been utilized.

Seismic evaluation of concrete moment frames in existing government buildings

2009 ◽  
Vol 36 (5) ◽  
pp. 813-825
Author(s):  
G. Akhras ◽  
W. Li
Keyword(s):  
Response Spectrum ◽  
Shear Walls ◽  
Linear Segment ◽  
Seismic Evaluation ◽  
Moment Frames ◽  
Limit States ◽  
Frame Element ◽  
Weak Beam ◽  
Detailed Evaluation ◽  
Column Joint

Many government departments have hundreds of buildings located in active seismic regions. Most of these buildings were built decades ago according to old design codes, and could be vulnerable to strong or even moderate earthquakes. To evaluate the seismic performance of concrete moment frames or moment frames with shear walls in these buildings, the static, vibration and modal response spectrum analyses are carried out according to the 2005 National building code of Canda NBCC. The analysis uses 2-D finite element models consisting of frame elements and inplane elements. The frame element has a built-in rigid linear segment at each end for modeling the portion within the beam–column joint, whereas the inplane element may have openings for modeling doors and windows in shear walls. The stiffness of both elements is adjusted to include effects of shear deformation in beams and bending deformation in wall piers. The results are further adjusted to incorporate effects of torsion and accidental torsion. Then, CSA-A23.3-04 is followed for detailed evaluation on safety in limit states, “strong column – weak beam” concept and shear strength requirements. Based on this approach, a new computer program is developed to perform this evaluation with minimum input data. Important issues in each step are discussed in detail. Examples are presented, and results are compared with available existing data.

scholarly journals Analisis Pengaruh Lokasi Dinding Geser Terhadap Pergeseran Lateral Bangunan Bertingkat Beton Bertulang 5 Lantai

2021 ◽  
Vol 4 (1) ◽  
pp. 16
Author(s):  
Leonardus Setia Budi Wibowo ◽  
Dermawan Zebua
Keyword(s):  
Lateral Displacement ◽  
Shear Walls ◽  
Seismic Loading ◽  
Shear Wall ◽  
Structural System ◽  
Earthquake Force ◽  
Earthquake Resistant ◽  
Story Drift ◽  
Frame System ◽  
Rc Shear Wall

Indonesia is one of the countries in the earthquake region. Therefore, it is necessary to build earthquake-resistant buildings to reduce the risk of material and life losses. Reinforced Concrete (RC) shear walls is one of effective structure element to resist earthquake forces. Applying RC shear wall can effectively reduce the displacement and story-drift of the structure. This research aims to study the effect of shear wall location in symmetric medium-rise building due to seismic loading. The symmetric medium rise-building is analyzed for earthquake force by considering two types of structural system. i.e. Frame system and Dual system. First model is open frame structural system and other three models are dual type structural system. The frame with shear walls at core and centrally placed at exterior frames showed significant reduction more than 80% lateral displacement at the top of structure.

scholarly journals Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

2015 ◽  
Vol 6 ◽  
pp. 845-856 ◽  
Author(s):  
Jana Vlachová ◽  
Rebekka König ◽  
Diethelm Johannsmann
Keyword(s):  
Imaginary Part ◽  
Coulomb Friction ◽  
Ambient Medium ◽  
Normal Load ◽  
Contact Stiffness ◽  
Oscillation Amplitude ◽  
Partial Slip ◽  
Squeeze Flow ◽  
Frictional Stress ◽  
The Real

The stiffness of micron-sized sphere–plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0–20 nm). The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM), where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate) (PMMA). The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson–Kendall–Roberts (JKR) model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo–Mindlin model. This finding is remarkable insofar, as the Cattaneo–Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor), which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting (i.e., a transport of shear stress across many small contacts, rather than a few large ones) can be exploited to reduce partial slip.

Seismic Damage Characteristics of RC Shear Wall with Diagonal Profile Steel Braces by Experiment

2007 ◽  
Vol 340-341 ◽  
pp. 1115-1120
Author(s):  
Shi Yun Xiao ◽  
Hong Nan Li ◽  
Yan Gang Zhao ◽  
Jing Wei Zhang
Keyword(s):  
Mechanical Model ◽  
Shear Walls ◽  
Shear Wall ◽  
Seismic Damage ◽  
Cyclic Loads ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Different Types ◽  
Rc Shear Wall ◽  
Theoretical Results

This paper focuses on an experimental investigation and theoretical analysis of different types of RC shear wall with the profile steel braces in two side columns and diagonal profile steel braces of walls subjected to applied repeated cyclic loads. Fifteen RC shear walls with different shear span ratio are tested and their aseismic charactertics are studied. The effect of profile steel bracings on failure property, bearing capacity, ductility and hysteretical characteristic of shear wall is investigated based on experimental results. It is shown that adding the profile steel braces on the boundary column and inner of walls can obviously enhance the ultimate strength of specimens and improve their aseismic characteristics. Finally, the mechanical model of the shear wall is presented and the formulae for calculating the load-carrying capacity are developed. Numerical analyses indicate that the theoretical results agree well with those from experiments.

scholarly journals Deformation Limits of L-Section RC Shear Walls

2016 ◽  
Vol 10 (1) ◽  
pp. 334-348
Author(s):  
Cui Ji-Dong ◽  
Han Xiao-Lei ◽  
Yang Wan ◽  
Li Wei-Chen
Keyword(s):  
Axial Load ◽  
Failure Modes ◽  
Shear Walls ◽  
Load Ratio ◽  
Shear Wall ◽  
Damage State ◽  
Shear Span ◽  
Axial Load Ratio ◽  
Set Up ◽  
Rc Shear Wall

In order to establish the relation between damage state and member deformation of the L-section RC shear wall, 216 FE models designed to meet the requirements of the Chinese codes were set up. The analysis fully considers the variation of parameters including axial load ratio and shear span ratio etc. According to the results, criteria of classifying failure modes of L-section RC shear walls are proposed. Failure modes are determined by shear-span ratio, moment-shear ratio and end columns' reinforcement ratio. Deformation limits corresponding to respective performance levels are put forward. Fitted formulas of calculating the limits are also presented. It is shown that the categorization criteria are reliably accurate in predicting failure modes. Deformation limits of a given L-section RC shear wall could be determined via axial load ratio and moment-shear ratio. The fitted formulas possess a satisfactory correlation with numerical results.

scholarly journals Slenderness Ratio and Influencing Parameters on the NL Behaviour of RC Shear Wall

2021 ◽  
Vol 7 (12) ◽  
pp. 2043-2067
Author(s):  
A. Atmani ◽  
Z. Boudaoud ◽  
N. Djebbar
Keyword(s):  
Structural Damage ◽  
Slenderness Ratio ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Reinforcement Ratio ◽  
Structural Elements ◽  
Concrete Compressive Strength ◽  
Flexural Behaviour ◽  
Zone Depth ◽  
Rc Shear Wall

Shear walls are very efficient structural elements to resist lateral seismic disturbance. Despite the aforementioned seismic performance, recent investigations report that they have suffered from significant structural damage after recent seismic activity, even for those complying with seismic provisions. These deficiencies in resistance and deformation capacities need to be explored. This study considers the influence of plastic length Lp, concrete compressive strength f_c28, longitudinal reinforcement ratio ρl, transverse reinforcement ratio ρsh, reduced axial load ν, confinement zone depth CS and focusing on the geometric slenderness λ. The parametric study has been conducted through NL pushover analysis using Peform3D software. The chosen coupled shear-flexure fiber macro model was calibrated with well-known cyclic experimental specimens. The paper points out the discrepancy between the two well-known codes EC8 and ASCE/SEI 41-13. In fact, the value of the slenderness ratio (λ) that trigger the beginning of a purely flexural behaviour recommended by EC8 (λ>2) is very different from the value of the ASCE/SEI 41-13 (λ>3) without accounting for the effect of the reduced axial force. Finally, it was found that RCW capacities are very sensitive to f_c28, ν, ρl, Lp and less sensitive to ρsh and CS. However, (λ) is the most decisive factor affecting the NL wall response. A new limit of slenderness and appropriate deformations of rotations are recommended to provide an immediate help to designers and an assistance to those involved with drafting codes. Doi: 10.28991/cej-2021-03091777 Full Text: PDF

scholarly journals Effect of Shear Wall on RC Building of Varying Heights

2019 ◽  
Vol 8 (12) ◽  
pp. 766-770
Keyword(s):  
Aspect Ratio ◽  
Response Spectrum ◽  
Shear Walls ◽  
Shear Wall ◽  
Seismic Zone ◽  
Lateral Loads ◽  
Base Shear ◽  
Aspect Ratios ◽  
Rc Building ◽  
The Comparative Study

Earthquake is an unexpected and expensive disaster for both livelihood and economy. In the modern day construction, there has been a lot of importance to make the structure resistant against lateral loads for multi storied building. Shear walls are an option of lateral load resisting system. The Concept of designing shear wall is to provide building structure with sufficient strength and deformation capacity to sustain the demands imposed by lateral loads with adequate margin of safety. The study focuses on effect of shear wall on R.C. building at different heights. For this purpose five models of different heights 15m, 30m, 45m, 60m and 75m and with different aspect ratios of 1.33, 0.66, 0.44, 0.33 and 0.26 respectively have been considered. All the models were designed for seismic zone V. For analysis purpose response spectrum method of analysis is considered as per IS: 1893-2002. The comparative study has been done for base shear, storey displacement, storey drift and storey stiffness. Utilization of shear walls when placed at corners of the building of low aspect ratio in high rise buildings is more effective compared to the low rise buildings of higher aspect ratio, as it gives the larger base shear and lesser displacement. The storey stiffness and storey drift is greatly improved when shear wall is placed at corners of the building

scholarly journals Effect of Shear Wall Location On Seismic Performance of High Raised Buildings

2021 ◽  
Vol 4 (1) ◽  
pp. 30-34
Author(s):  
Gajagantarao Sai Kumar ◽  
Purushotham Rao ◽  
Partheepan Ganesan
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
Shear Walls ◽  
Shear Wall ◽  
Existing Structures ◽  
Maximum Stiffness ◽  
Earthquake Resistant Structures ◽  
Minimum Displacement ◽  
Earthquake Zone

Multi-storey buildings tend to get damaged mainly during earthquake. Seismic analysis is a tool for the estimation of structural response in the process of designing earthquake resistant structures and/or retrofitting vulnerable existing structures. The principle purpose of this work is to analyze and design a building with a shear wall and also to find the appropriate position of shear wall that result in maximum resistance towards lateral forces and minimum displacement of the structure. In this study, a G+7 multi-storey building of 15 m ×20 m in plan area has been chosen and modelled using ETABS. The developed model was validated by solving manually and the results were validated in ETABS. Thereafter, 4 different new plans were modelled in ETABS located in the same earthquake zone area. These plans have shear wall concepts are implemented on the building at four different locations. Seismic, vibration and response spectrum analysis were performed on these structures. Salient parameters such as storey stiffness, storey displacement and storey drift were computed using the ETABS model. These were compared with that of the frame having no shear walls. By comparing the results obtained at different shear wall locations, the best plan with the shear wall having minimum lateral storey displacement and maximum stiffness is suggested for this location.

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