scholarly journals Seismic resistance of reinforced concrete-masonry shear walls with high steel percentages

1977 ◽  
Vol 10 (1) ◽  
pp. 1-16
Author(s):  
M. J. N. Priestley
Keyword(s):  
Shear Stress ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Hysteresis Loops ◽  
Shear Walls ◽  
Shear Stresses ◽  
Test Results ◽  
Displacement Ductility ◽  
Ultimate Shear Stress ◽  
Concrete Masonry

This paper summarizes test results of six heavily reinforced concrete masonry shear walls. The test programme was designed to investigate the necessity for the low ultimate shear stress specified by Masonry codes. Care was taken to accurately model good, but realistic design practice in detailing, and variables investigated in the series included steel percentage, influence of vertical load and confinement of potential crushing areas by mortar bed confining plates. Results are presented which clearly indicate that the maximum current code allowance for ultimate shear stress is unreasonably low. No wall suffered diagonal shear failure despite maximum shear stresses exceeding
four times the maximum code level. All walls displayed stable hysteresis loops at a displacement ductility factor of 2, and the less heavily reinforced walls (designed to approximately twice code levels) were satisfactory at
 DF = 4. Degradation was never catastrophic and occurred due to slip of the entire wall along the foundation beam. Methods for reducing the degradation are discussed. Confining plates did not significantly reduce the degradation of the hysteresis loops, but substantially reduced damage to the walls
 at high ductility factors. Values of required ductility for walls designed to the Loadings Code are investigated, and on the basis of these and the experimental results, recommendations are made for relaxation to the ultimate shear provisions of the masonry code.

scholarly journals Nonlinear Finite Element Analysis Formulation for Shear in Reinforced Concrete Beams

2019 ◽  
Vol 9 (17) ◽  
pp. 3503 ◽  
Author(s):  
Sang-Ho Kim ◽  
Sun-Jin Han ◽  
Kang Kim
Keyword(s):  
Shear Stress ◽  
Reinforced Concrete ◽  
Stress Function ◽  
Shear Stresses ◽  
Rc Beams ◽  
Test Results ◽  
Proposed Model ◽  
Load Displacement ◽  
Shear Stress Function ◽  
Column Element

This study suggests a novel beam-column element formulation that utilizes an equilibrium-driven shear stress function. The beam shear is obtained from the bi-axial states of micro-planes, through matrix condensation and zero vertical traction assumptions. This properly remedies the shear stiffening of a one-dimensional beam-column element, keeping its degrees of freedom to a minimum. For verification of the proposed method, a total of seven shear test results of reinforced concrete (RC) beams were collected from the literature, in which the key variables were the reinforcement ratio, the presence of shear reinforcement, and section shape. The advantages are clearly shown in the shear stresses distributions being accurately described and the global load-displacement relations being successfully obtained and matching well with various test results. The proposed model shows satisfactory descriptions of the monotonic load-displacement response of the RC beams failing in multiple modes that vary from diagonal-tension to flexural-compression. In addition, more accurate and reliable information of sectional responses including sectional shear deformation and stresses is collected, leading to better prediction of a potential shear failure mode. Finally, the advantages of the proposed model are demonstrated by comparing the analysis results of an RCT-beam by using the different shear assumptions that include the constant and parabolic shear strains, constant shear flow, and the proposed shear stress function.

scholarly journals Influence of wave effect on fiber stress limit under tensile tests of composite material

2020 ◽  
Vol 19 (4) ◽  
pp. 310-316
Author(s):  
I. R. Antypas ◽  
Amer Karnoub ◽  
A. G. Dyachenkо
Keyword(s):  
Shear Stress ◽  
Composite Material ◽  
Shear Failure ◽  
Fibrous Structure ◽  
Shear Stresses ◽  
Test Results ◽  
Wave Effect ◽  
Tensile Stresses ◽  
Fiber Angle ◽  
The Impact

Introduction. The response of composite materials to the impact of a certain kind of load is difficult to predict, therefore, research in this area has often been neglected. The work objective was to study the influence of the wave effect on the tensile strength of polymer composites of a fibrous structure.Materials and Methods. In the tests, samples of multilayer materials of various thicknesses with continuous, long and short fibers that form a fabric, as well as a layered structure, were used. The number of layers corresponds to the resistance to the applied loads. Fibers of glass, carbon, kevlar, or their combinations were used. Isotropic materials – epoxide, polyester and vinyl ether – were used as binders.Research Results. The tensile test results of homogeneous samples and samples of fibrous structure are obtained. In this case, the values of fiber angle varied. The stability of their intercomparison test results is established. The dependence of the maximum tensile stresses σmax, MPa, (on the vertical axis) on the fiber angle θmax is obtained. These stresses for a fibreless material amounted to 250 MPa. Normal and tangential stresses acting perpendicular to the fibers, as well as shear stresses of the layered material, are calculated. As follows from the analysis of the dependences for the significant tensile stresses and from the study on refraction in the section of the sample damage, it was established that the shear stress τ???????????????? was the cause of the fracture. Using an equation providing the compensation for the angle of inclination θ = 45, it was determined that the shear stress of the polyester is τху = 35 MPa. This was the stress that caused subsequently the destruction of the samples.Discussion and Conclusions. The tensile stresses of the composite material decrease with increasing the fiber angle in certain areas. The destruction of all fiber samples occurred when the shear stress reached a value approximately equal to the shear stress at which the destruction of samples made only from a binder material happened. When the specimen broke, the fracture mode had the form similar to the shear failure; besides, at the moment of fracture, the object having a rectangular shape, being deformed at an angle, took the form of a parallelogram.

scholarly journals A Monotonic Smeared Truss Model to Predict the Envelope Shear Stress—Shear Strain Curve for Reinforced Concrete Panel Elements under Cyclic Shear

2021 ◽  
Vol 2 (1) ◽  
pp. 174-194
Author(s):  
Luís Bernardo ◽  
Saffana Sadieh
Keyword(s):  
Shear Stress ◽  
Reinforced Concrete ◽  
Shear Strain ◽  
Peak Load ◽  
Strain Curve ◽  
Fiber Reinforced Polymers ◽  
Shear Stresses ◽  
Cyclic Shear ◽  
Concrete Panels ◽  
Truss Model

In previous studies, a smeared truss model based on a refinement of the rotating-angle softened truss model (RA-STM) was proposed to predict the full response of structural concrete panel elements under in-plane monotonic loading. This model, called the “efficient RA-STM procedure”, was validated against the experimental results of reinforced and prestressed concrete panels, steel fiber concrete panels, and reinforced concrete panels externally strengthened with fiber-reinforced polymers. The model incorporates equilibrium and compatibility equations, as well as appropriate smeared constitutive laws of the materials. Besides, it incorporates an efficient algorithm for the calculation procedure to compute the solution points without using the classical trial-and-error technique, providing high numerical efficiency and stability. In this study, the efficient RA-STM procedure is adapted and checked against some experimental data related to reinforced concrete (RC) panels tested under in-plane cyclic shear until failure and found in the literature. Being a monotonic model, the predictions from the model are compared with the experimental envelopes of the hysteretic shear stress–shear strain loops. It is shown that the predictions for the shape (at least until the peak load is reached) and for key shear stresses (namely, cracking, yielding, and maximum shear stresses) of the envelope shear stress–shear strain curves are in reasonably good agreement with the experimental ones. From the obtained results, the efficient RA-STM procedure can be considered as a reliable model to predict some important features of the response of RC panels under cyclic shear, at least for a precheck analysis or predesign.

Experimental Study on the Structural Performance of Beam-Column Joints in Old Buildings without Designed Shear Reinforcement under Earthquake

2017 ◽  
Vol 902 ◽  
pp. 33-40
Author(s):  
Cong Thuat Dang ◽  
Ngoc Hieu Dinh
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Test Results ◽  
Shear Reinforcement ◽  
Reinforcing Bars ◽  
Reinforced Concrete Buildings ◽  
Concrete Buildings ◽  
Gravity Load ◽  
Load Beam

Old reinforced concrete buildings constructed around 1980’s in many developing countries have been designed against mainly gravity load. Beam-column joints in these buildings contain slightly or no shear reinforcement inside the panel zones due to the construction convenience, and are vulnerable to shear failure in beam-column joints under the action of earthquake loads, especially for the exterior beam-column joints. This experimental study aimed to investigate the seismic performance of five half-scale exterior beam-column joints simulating the joints in existing reinforced-concrete buildings with non-shear hoop details. The test results showed that the structural performances of the beam-column joints under earthquake including failure mode, load-drift ratio relationship, shear strain of the joints and energy dissipation are strongly affected by the amount of longitudinal reinforcing bars of beams.

Behavior of fully grouted reinforced concrete masonry shear walls failing in flexure: Analysis

2009 ◽  
Vol 31 (9) ◽  
pp. 2032-2044 ◽  
Author(s):  
Marwan T. Shedid ◽  
Wael W. El-Dakhakhni ◽  
Robert G. Drysdale
Keyword(s):  
Reinforced Concrete ◽  
Shear Walls ◽  
Concrete Masonry

scholarly journals Hysteretic Behavior of Steel Reinforced Concrete Columns Based on Damage Analysis

2019 ◽  
Vol 9 (4) ◽  
pp. 687 ◽  
Author(s):  
Bin Wang ◽  
Guang Huo ◽  
Yongfeng Sun ◽  
Shansuo Zheng
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Hysteresis Loops ◽  
Time History ◽  
Hysteretic Behavior ◽  
Loading Path ◽  
Test Results ◽  
Hysteresis Model ◽  
Skeleton Curve ◽  
Steel Reinforced Concrete

With the aim to model the seismic behavior of steel reinforced concrete (SRC) frame columns, in this research, hysteresis and skeleton curves were obtained based on the damage test results of SRC frame columns under low cyclic repeat loading and the hysteretic behavior of the frame columns was further analyzed. Then, the skeleton curve and hysteresis loops were further simplified. The simplified skeleton curve model was obtained through the corresponding feature points obtained by mechanical and regression analysis. The nonlinear combination seismic damage index, which was developed by the test results and can well reflect the effect of the loading path and the number of loading cycle of SRC frame columns, was used to establish the cyclic degradation index. The strength and stiffness degradation rule of the SRC frame columns was analyzed further by considering the effect of the accumulated damage caused by an earthquake. Finally, the hysteresis model of the SRC frame columns was established, and the specific hysteresis rules were given. The validity of the developed hysteresis model was verified by e comparison between the calculated results and the test results. The results showed that the model could describe the hysteresis characteristics of the SRC frame columns under cyclic loading and provide guidance for the elastoplastic time-history analysis of these structures.

scholarly journals Seismic Failure Modes and Deformation Capacity of Reinforced Concrete Columns under Cyclic Loads

2017 ◽  
Vol 62 (1) ◽  
pp. 80-91 ◽  
Author(s):  
Ma Ying ◽  
Gong Jin-xin
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Axial Load ◽  
Failure Modes ◽  
Shear Failure ◽  
Hysteresis Loops ◽  
Load Ratio ◽  
Deformation Capacity ◽  
Static Test ◽  
Total Displacement

This paper investigates the seismic failure modes and horizontal deformation capacity of reinforced concrete square columns based on the pseudo-static test. The controlled variables include shear aspect ratio, axial load ratio and stirrup spacing. The seismic failure modes, the inelastic deformation capacity after yielding and the deformation components due to flexure, shear and anchorage slip of the RC columns were analyzed, especially flexural-shear failure. The results show that decreasing shear aspect ratio, or increasing axial load or stirrup spacing can result in the change of column failure mode from flexural failure to flexural- shear failure or shear failure, the pinching of hysteresis loops, the reductions of hysteresis loop area and deformation capacity. With the increase of total displacement, all three displacement components increased; the contribution of flexure displacement in total displacement reduced, the contribution of shear displacement increased, the contribution of anchorage slip displacement changed in the range of 30%- 40%.

Seismic Performance of Cantilever-Reinforced Concrete Masonry Shear Walls

2014 ◽  
Vol 140 (9) ◽  
pp. 04014051 ◽  
Author(s):  
Farhad Ahmadi ◽  
Jaime Hernandez ◽  
Jacob Sherman ◽  
Christina Kapoi ◽  
Richard E. Klingner ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Shear Walls ◽  
Concrete Masonry

Effects of in-plane loading on the out-of-plane stability of slender reinforced concrete masonry shear walls

2016 ◽  
pp. 1847-1856 ◽  
Author(s):  
B.R. Robazza ◽  
T.Y. Yang ◽  
K.J. Elwood ◽  
D.L. Anderson ◽  
S. Brzev ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Shear Walls ◽  
Concrete Masonry ◽  
Out Of Plane
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