scholarly journals A simplified method to predict the ultimate shear stress of reinforced concrete membrane elements

2013 ◽  
Vol 49 ◽  
pp. 329-344 ◽  
Author(s):  
Pedro F. Miguel ◽  
Juan Navarro-Gregori ◽  
Miguel A. Fernández-Prada ◽  
José L. Bonet
Keyword(s):  
Shear Stress ◽  
Reinforced Concrete ◽  
Ultimate Shear Stress ◽  
Simplified Method

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 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.

scholarly journals Numerical investigation of the impact of branching vessel boundary conditions on aortic hemodynamics

2017 ◽  
Vol 3 (2) ◽  
pp. 321-324 ◽  
Author(s):  
Pavlo Yevtushenko ◽  
Florian Hellmeier ◽  
Jan Bruening ◽  
Titus Kuehne ◽  
Leonid Goubergrits
Keyword(s):  
Shear Stress ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Reference Method ◽  
Patient Specific ◽  
Simplified Method ◽  
The Mean ◽  
The Impact ◽  
Significant Attention ◽  
Aortic Hemodynamics

AbstractCFD has gained significant attention as a tool to model aortic hemodynamics. However, obtaining accurate patient-specific boundary conditions still poses a major challenge and represents a major source of uncertainties, which are difficult to quantify. This study presents an attempt to quantify these uncertainties by comparing 14 patient-specific simulations of the aorta (reference method), each exhibiting stenosis, against simulations using the same geometries without the branching vessels of the aortic arch (simplified method).Results were evaluated by comparing pressure drop along the aorta, secondary flow degree (SFD) and surface-averaged wall shear stress (WSS) for each patient. The comparison shows little difference in pressure drop between the two methods (simplified-reference) with the mean difference being 1.2 mmHg (standard deviation: 3.0 mmHg). SFD and WSS, however, show striking differences between the methods: SFD downstream of the stenosis is on average 61 % higher in the simplified cases, while WSS is on average 3.0 Pa lower in the simplified cases.Although unphysiological, the comparison of both methods gives an upper bound for the error introduced by uncertainties in branching vessel boundary conditions. For the pressure drop this error appears to be remarkably low, while being unacceptably high for SFD and WSS.

Sign in / Sign up

Export Citation Format

Share Document