scholarly journals Aspects of drift and ductility capacity of rectangular cantilever structural walls

1998 ◽  
Vol 31 (2) ◽  
pp. 73-85 ◽  
Author(s):  
M. J. N. Priestley ◽  
M. J. Kowalsky
Keyword(s):  
Damage Control ◽  
Shear Walls ◽  
Load Ratio ◽  
Longitudinal Reinforcement ◽  
Structural Walls ◽  
Displacement Ductility ◽  
Drift Capacity ◽  
Aspect Ratios ◽  
Axial Load Ratio ◽  
Ductility Capacity

Moment-curvature analyses of cantilever shear walls are used to show that yield curvature, serviceability curvature, and ultimate (damage-control) curvature are insensitive to variations of axial load ratio, longitudinal reinforcement ratio, and distribution of longitudinal reinforcement. The results are used to determine available displacement ductility factors for walls of different aspect ratios and drift limits. It is shown that drift capacity will generally exceed code levels of permissible drift, and that code drift limits will normally restrict, sometimes severely, the design displacement ductility factor.

scholarly journals Simplified Data-Driven Model for the Moment Curvature of T-Shaped RC Shear Walls

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Bin Wang ◽  
Wenzhe Cai ◽  
Qingxuan Shi
Keyword(s):  
Cross Sections ◽  
Limit State ◽  
Shear Walls ◽  
Load Ratio ◽  
Ultimate Limit State ◽  
Limit States ◽  
Displacement Ductility ◽  
And Performance ◽  
Displacement Based ◽  
Ductility Capacity

Sectional deformation quantities, such as curvature and ductility, are of prime significance in the displacement-based seismic design and performance evaluation of structural members. However, few studies on the estimates of curvatures at different limit states have been performed on asymmetric flanged walls. In this paper, a parametric study was performed for a series of T-shaped wall cross-sections based on moment-curvature analyses. By investigating the effects of the axial load ratio, reinforcement content, material properties, and geometric parameters on curvatures at the yield and ultimate limit state, we interpret the variation in curvature with different influencing factors in detail according to the changes of the neutral axis depth. Based on the regression analyses of the numerical results of 4941 T-shaped cross-sections, simple expressions to estimate the yield curvature and ultimate curvature for asymmetric flanged walls are developed, and simplified estimates of the ductility capacity including curvature ductility and displacement ductility are further deduced. By comparing with the experimental results, we verify the accuracy of the proposed formulas. Such simple expressions will be valuable for the determination of the displacement response of asymmetric flanged reinforced concrete walls.

Optimal Trends in Seismic Design of Single Column Circular Reinforced Concrete Bridge Piers

1994 ◽  
Vol 10 (3) ◽  
pp. 589-614
Author(s):  
Ravindra Verma ◽  
M. J. Nigel Priestley
Keyword(s):  
Axial Load ◽  
Load Ratio ◽  
Bridge Piers ◽  
Column Height ◽  
Column Diameter ◽  
Displacement Ductility ◽  
Reinforced Concrete Bridge ◽  
Axial Load Ratio ◽  
Single Column ◽  
Ductility Capacity

An algorithm is developed to incorporate seismic capacity design philosophy in a computer program for the optimal design of single column circular reinforced concrete bridge piers for seismic loading. The program designs the circular column as a single degree of freedom system under the combined effect of axial and lateral seismic loads over a broad range of axial load ratio, column height and design displacement ductility capacity. Flexural, confinement and shear reinforcement requirements are then assessed for the entire range of parameters and cost calculations performed. For a given column height, design displacement ductility and axial load level, results indicate the existence of an optimal column diameter and ductility level. As the column diameter is reduced, cost savings are effected by reduced volume of concrete, but tend to be offset by P-Δ effects, increased longitudinal reinforcement for flexure, and increased transverse reinforcement for confinement and shear. Based on common trends, solutions are provided for the most economical range of the axial load ratio and design displacement ductility capacity for a given column height.

scholarly journals Assessment of ultimate drift capacity of RC shear walls by key design parameters

2017 ◽  
Vol 50 (4) ◽  
pp. 482-493 ◽  
Author(s):  
Chanipa Netrattana ◽  
Rafik Taleb ◽  
Hidekazu Watanabe ◽  
Susumu Kono ◽  
David Mukai ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Axial Load ◽  
Concrete Strength ◽  
Shear Walls ◽  
Load Ratio ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
Drift Capacity ◽  
Axial Load Ratio

The latest version of the Standard for Structural Calculation of Reinforced Concrete Structures, published by the Architectural Institute of Japan in 2010 [1], allows the design of shear walls with rectangular cross sections in addition to shear walls with boundary columns at the end regions (referred to here as “barbell shape”). In recent earthquakes, several reinforced concrete (RC) shear walls were damaged by flexural failures through concrete compression crushing accompanied with buckling of longitudinal reinforcement in the boundary areas. Damage levels have clearly been shown to be related to drift in structures; this is why drift limits are in place for structural design criteria. A crucial step in designing a structure to accommodate these drift limits is to model the ultimate drift capacity. Thus, in order to reduce damage from this failure mode, the ultimate drift capacity of RC shear walls needs to be estimated accurately. In this paper, a parametric study of the seismic behaviour of RC shear walls was conducted using a fibre-based model to investigate the influence of basic design parameters including concrete strength, volumetric ratio of transverse reinforcement in the confined area, axial load ratio and boundary column dimensions. This study focused on ultimate drift capacity for both shear walls with rectangular sections and shear walls with boundary columns. The fibre-based model was calibrated with experimental results of twenty eight tests on shear walls with confinement in the boundary regions. It was found that ultimate drift capacity is most sensitive to axial load ratio; increase of axial load deteriorated ultimate drift capacity dramatically. Two other secondary factors were: increased concrete strength slightly reduced ultimate drift capacity while increased shear reinforcement ratio and boundary column width improved ultimate drift capacity.

scholarly journals Shear and Flexural Stiffnesses of Reinforced Concrete Shear Walls Subjected to Cyclic Loading

2014 ◽  
Vol 8 (1) ◽  
pp. 104-121 ◽  
Author(s):  
T. O. Tang ◽  
R. K.L. Su
Keyword(s):  
Seismic Analysis ◽  
Classical Mechanics ◽  
Shear Walls ◽  
Shear Stiffness ◽  
Eurocode 8 ◽  
Design Codes ◽  
Structural Walls ◽  
Load Distributions ◽  
Classical Models ◽  
Ductility Capacity

Seismic analyses of concrete structures under maximum-considered earthquakes require the use of reduced stiffness accounting for cracks and degraded materials. Structural walls, different to other flexural dominated components, are sensitive to both shear and flexural stiffness degradations. Adoption of the gross shear stiffness for walls in seismic analysis prevails particularly for the design codes in the US. Yet available experimental results indicate that this could overstate the shear stiffness by more than double, which would hamper the actual predictions of building periods and shear load distributions among columns and walls. In addition, the deformation capacity could be drastically understated if the stipulated constant ductility capacity is adopted. This paper reviews the available simplified shear and flexural models, which stem from classical mechanics, empirical formulations and/or parametric studies, suitable for structural walls at the state-of-the-art. Reviews on the recommended flexural and shear stiffnesses by prominent design codes such as ACI318-11, Eurocode 8 and CSA are included. A database comprised of walls subjected to reverse-cyclic loads is formed to evaluate the performance of each model. It is found that there exist classical models that could outweigh overconservative codified values with comparable simplicity for practical uses.

Seismic response of structural walls: recent developments

2001 ◽  
Vol 28 (6) ◽  
pp. 922-937 ◽  
Author(s):  
T Paulay
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Seismic Design ◽  
Limit State ◽  
Lateral Force ◽  
Structural Walls ◽  
Structural Class ◽  
Response Component ◽  
Displacement Ductility ◽  
Ductility Capacity

It is postulated that for purposes of seismic design, the ductile behaviour of lateral force-resisting wall components, elements, and indeed the entire system can be satisfactorily simulated by bilinear force–displacement modeling. This enables displacement relationships between the system and its constituent components at a particular limit state to be readily established. To this end, some widely used fallacies, relevant to the transition from the elastic to the plastic domain of behaviour, are exposed. A redefinition of stiffness and yield displacement allows more realistic predictions of the important feature of seismic response, component displacements, to be made. The concepts are rational, yet very simple. Their applications are interwoven with the designer's intentions. Contrary to current design practice, whereby a specific global displacement ductility capacity is prescribed for a particular structural class, the designer can determine the acceptable displacement demand to be imposed on the system. This should protect critical components against excessive displacements. Specific intended displacement demands and capacities of systems comprising reinforced concrete cantilever and coupled walls can be estimated.Key words: ductility, displacements, reinforced concrete, seismic design, stiffness, structural walls.

Research on Deformation Capacity Design Method of Steel High Performance Concrete Structural Walls

2010 ◽  
Vol 163-167 ◽  
pp. 1540-1546
Author(s):  
Liang Bai ◽  
Tian Hua Zhou ◽  
Xing Wen Liang
Keyword(s):  
Axial Load ◽  
High Performance ◽  
High Performance Concrete ◽  
Design Method ◽  
Load Ratio ◽  
Deformation Capacity ◽  
Capacity Design ◽  
Structural Walls ◽  
Axial Load Ratio ◽  
Characteristic Value

The cyclic loading test of three steel high performance concrete(SHPC) structural walls was conducted and the failure pattern of the structural walls under the combined effect of axial force, bending moment, and shear force was researched. Based on the experimental results, the displacement-based deformation capacity design method was proposed for SHPC structural walls. It is obtained for the interrelated relationships among the ultimate drift ratio, the axial load ratio, the characteristic value of stirrup content and the aspect ratio. It is concluded that the increasing the characteristic value of stirrup content and limiting the axial load ratio were effective means to improve ductility. The characteristic value of stirrup content of SHPC structural walls with different ultimate drift ratio and axial load ratio were proposed and the conclusion can be referred by the design of SHPC structural walls.

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 Experimental Investigation on Seismic Resistance of RC Shear Walls with CFRP Bars in Boundary Elements

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Jun Zhao ◽  
Fuqiang Shen ◽  
Chenzhe Si ◽  
Yuping Sun ◽  
Lu Yin
Keyword(s):  
Experimental Investigation ◽  
Energy Dissipation ◽  
Axial Load ◽  
Residual Deformation ◽  
Shear Walls ◽  
Load Ratio ◽  
Boundary Elements ◽  
Cumulative Energy ◽  
Equivalent Viscous Damping ◽  
Axial Load Ratio

AbstractExperimental investigation on seismic performance of RC shear walls reinforced with CFRP bars in boundary elements to enhance the resilience was presented which is expected for stable resistance capacity and small residual deformation. Six RC shear walls reinforced with CFRP bars as longitudinal tensile materials in boundary elements were tested under reversed cyclic lateral loading while subjected to constant axial compression with different axial load ratios of 0.17, 0.26 and 0.33, respectively. Two forms of stirrups were used for each axial load ratio, which were rectangular and circular stirrups in boundary elements. A reference specimen, ordinary RC shear walls, was also introduced to certify the excellence of CFRP bars. The test results indicated that the walls utilizing CFRP bars had small residual deformations and residual crack widths. Lower crack propagation height and larger concrete crushing region, bearing capacity and equivalent viscous damping coefficient (EVDC) could be observed with the increase of axial load ratios. The effects of stirrup forms on experimental results had a relation to the axial load ratio. When the axial load ratio was small, the shear walls with circular stirrups had better energy dissipation than that with rectangular stirrups at a given drift level, while the cumulative energy dissipation (CED) were similar. With the increase of axial load ratio, the walls exhibited similar energy dissipation at the same drift level, however, the shear walls with rectangular stirrups had larger CED.

Deformation-Based Nonlinear Finite Element Analysis of Steel High Performance Concrete Structural Walls

2012 ◽  
Vol 166-169 ◽  
pp. 797-802
Author(s):  
Ma Kaize
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Load ◽  
High Performance ◽  
Load Ratio ◽  
Nonlinear Finite Element ◽  
Structural Walls ◽  
Steel Ratio ◽  
Axial Load Ratio ◽  
Characteristic Value

Base on the experiment results of steel high performance reinforced concrete (SHPRC) structural walls, nonlinear finite element(FE) analysis is performed to simulate the complete process of the loading and concrete crack of SHPRC structural walls in the platform of ABAQUS. The nonlinear of material is taken into account in the models. The reliability of the finite element model is verified through the comparison of the analysis results and the experimental results. Based on the proposed model, the parametric analysis is carried out to study the effect of axial load ratio, aspect ratio, stirrup characteristic value, and steel ratio on the seismic behavior of SHPRC structural walls. It is concluded that the bearing capacity of SHPRC structural walls increase with the increase of the axial load ratio, but the deformation decreases obviously. The deformation and bearing capacity of the structural walls are improved by increasing the steel ratio. With increasing the stirrup characteristic value, the deformation of the structural walls improves significantly. The stirrup characteristic values are proposed to ensure the SHPRC structural walls for different axial load ratios meet the deformation capacity of drift ratio of 1/120,1/100 and 1/80, respectively.

Experimental Evaluation of the Seismic Performance of Circular Reinforced Concrete Bridge Columns

2011 ◽  
Vol 50-51 ◽  
pp. 547-553
Author(s):  
Gang Zheng ◽  
Gui Qian Li
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Load Ratio ◽  
Bridge Columns ◽  
Reinforcement Ratio ◽  
Concrete Bridge ◽  
Longitudinal Reinforcement ◽  
Shear Span ◽  
Reinforced Concrete Bridge ◽  
Axial Load Ratio

Based on the basic requirements of current Guidelines for Seismic Design of Highway Bridges, the orthogonal quasi-static test of four factors (shear-span ratio, longitudinal reinforcement diameter, axial-load ratio and spiral reinforcement ratio) at three different levels for circular reinforced concrete bridge columns has been designed. With test data the damage state, displacement ductility, capacity of accumulative energy dissipation to ultimate displacement state of bridge columns subjected to low-cyclic loading have been analyzed systematically so as to investigate effects of factors such as shear-span ratio, axial-load ratio, longitudinal reinforcement ratio and spiral reinforcement ratio on ductility performance of bridge columns.

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