Sharif Digital Repository

This paper focuses on the performance evaluation of several concrete models in reinforced concrete (RC) structures subjected to seismic loading. Despite many studies conducted on implementing different characteristics of concrete in constitutive models, there is an essential need for investigating the ability of these models in predicting the behavior of structures in seismic applications. In this paper, several developed plasticity-based constitutive models with the combination of fracture and continuum damage models are investigated for application in seismic loading conditions. Damage-based isotropic and anisotropic models and smeared cracking approach have been applied as complementary... 

One of the major shortcomings of conventional and rather high-rise structures is increasing lateral displacements arising from lateral forces which finally make the entire project un-economical. In this research, effort has been made to investigate the effect of shear walls arrangements on the lateral displacement of the structure. Two types of structures including 16 and 32-storeys frameswith different arrangements of shear panels were examined. The findings indicate that compared to other frames, the performance of frame no. 1 in both types of structures was poor in controlling the overall displacement of structure. Furthermore, more number of shear panels are not necessarily effective in... 

This article describes the results of experimental observations in pulsating Simple Shear Flows (SSF). A uniform-mean-gradient shear flow was generated within the test section of an open circuit wind tunnel. Transverse arrays of honeycomb channels with differing resistances were used to generate shear flow at low shear rates (less than 20 s-1). A set of rotating vanes pulsated the flow field at 8.5 Hz and 18 Hz. Instantaneous velocity was measured by employing a two-component hot wire anemometry technique. The experimental credibility of the facility was established in stationary SSF. In pulsating flows the pulsation effects on mean shear rate, the kinetic energy of turbulence, Reynolds... 

In this paper, pulsating grid-generated turbulence is studied. A two-component hot wire anemometry technique is used. The pulsation effects on characterizing lenght scales and the statistical description of fluctuations are studied in comparison with their stationary counterparts. No significant change in the character of the turbulent flow with pulsation is observed  

Effect of different conditions on shear behaviour of rock has been investigated by various researchers. As known, in larger scale the continuity of the rock material is interrupted by separated planes such as bedding planes, faults, shear zones, closure and the behaviour converts to be inelastic and anisotropic. Generally, discontinuities appear repeatedly in more than one preferential direction, creating a three dimensional structure, reducing its stiffness and shear strength as mechanical effects and increasing its transport velocity associated with discontinuity flow as hydraulic effects. They also make rock behavior more complex and different compared to the behavior of soil. According... 

The results of several monotonioc push-out tests on polypropylene concrete with channel shear connectors are presented in this research. The results are compared with ordinary concrete specimens with the same test setup. The effect of confining reinforcement on the shear capacity and ductility of polypropylene concrete composite system is investigated  

In the present study, an analytical solution is proposed to determine the interlaminar stresses in long symmetric laminated composite plates subjected to shearing loads. An improved first-order shear deformation theory (IFSDT) and a simplified IFSDT (SIFSDT) are utilized to calculate the unknown constants appearing in the reduced elasticity displacement field which actually demonstrate the global deformations of the plate. Then the numerical values of the interlaminar normal and shear stresses are established through the laminates by using Reddy's layerwise theory. Finally, several numerical examples are presented to study the interlaminar stresses in the interfaces of the layers and through... 

Different ways have been presented to prevent elastic buckling of steel shear walls. One of these solutions is corrugated shear wall. In this type of wall, shear buckling strength increases without increasing the thickness of the panel. Numerical modeling results indicate that, always, shear buckling strength of corrugated panels is more than the flat panels and with the right choice of the geometric parameters of corrugated panels; without increasing the thickness of the panel, we can improve buckling strength significantly. In the trapezoidal corrugated panels, reducing the width of the subpanels do not always increase buckling strength of the panel, but it changes the panel buckling shape... 

The main goal of this study is to further understanding of the role of rubber particles on deformation mechanisms in PP/EPR blend. For doing this standard tensile specimens were produced using injection molding. The results of microscopic evaluation of tensile specimen after some stretching show that damage forms in some points and then propagates in different directions. Also some elongated voids are observed, those are probably formed due to cavitation of rubber particles or debonding at the interface. With regard to achieved micrographs one may conclude that the deformation mechanism in PP/EPR blend can be massive dilatational shear banding due to repeated cavitation. © 2003 Elsevier Ltd.... 

The Ni-base superalloy GTD-111 is used as a blading material in the first stage blades of high power gas turbines. The creep-rupture properties of the cast superalloy were studied over a wide range of temperatures and stresses. The observations of dislocation structures during steady-state creep confirmed that the creep mechanism was different in the high and low stress regions. The results showed that in the high stress region, shear mechanisms including stacking fault formation and anti-phase boundary creation were operative and in the low stress region, a by-passing mechanism occurred by either looping or dislocation climb and glide. With increasing exposure time in the high-temperature... 

The individual and combined effect of shear deformation and rotary inertia on the columns was discussed. It was shown that the shear deformation effect always tends to reduce the buckling load. It was observed that rotary inertia for supported columns has no effect on the buckling load. The critical buckling load of perfect columns subjected to static axial loading was calculated using the Euler-Bernoulli theory  

It is well known that shear strength of beams without stirrups shows a strong size effect. At present, several formulas of size effect are used by some codes and suggested by various researchers. Most of those formulas are not in agree with fracture mechanics. Recently, a simple formula based on modified compression field theory, MCFT, was proposed (Collins and Kuchma [1], Lubell et al. [2]), which shows a size effect stronger than the size effect formula based on fracture mechanics, proposed by Bazant (e.g. Bazant and Kazemi [3], Bazant and Yu [4]). In this paper it is shown that with some refined considerations, formulas are resulted in agree with Fracture Mechanics concept. In the derived... 

A mixed shear-flexural beam element, which is called VM link element, is introduced. Dissimilar multi-surfaces in the shear-flexural space and non zero off diagonal components in flexibility matrixes are used for more realistic modeling of inelastic shear-flexural interaction. For preventing of intersecting among the yield surfaces, a new non-associated flow rule and a new kinematic hardening rule are developed. Capability of this element is examined for shear links used in eccentrically braced frames analysis for cyclic loading. It is shown that, the proposed link element is in a good agreement with the existing test results  

The small-strain shear modulus, Go, is an important fundamental soil property. Although many studies have been conducted on this property for clean sands and pure clays, small-strain behavior for mixtures of sand and fines has been less addressed. This paper presents the results of a comprehensive laboratory study on G0 value of sand containing various amounts of different fines. To this aim, bender elements were integrated into a conventional triaxial apparatus, and shear wave velocity was measured on samples of sand with different amounts of highly-plastic, medium-plastic, low-plastic, or non-plastic fines at different void ratios. Measuring the shear wave velocity and thus... 

Corrugated steel plate and simple steel plate shear wall construction is a widely accepted and efficient lateral force resisting construction. The widespread use is motivated by the large initial stiffness, high level of energy absorption, and ability to accommodate openings. There is a dearth of information regarding the detailed nonlinear, inelastic behavior of corrugated steel plate shear walls, particularly walls with openings. Presented here are the results of a detailed, numerical parametric study comparing corrugated steel plate and simple steel plate shear walls, with and without openings. Parameters studied are plate thickness, angle of corrugation, opening size, and opening... 

This paper presents results from a series of constant normal load direct shear tests on artificially created rock joints, in an attempt to quantify the effects of different factors that contribute to the shear strength along "ideal" rock joints. Particular focus is given to the effect of asperity orientation with respect to the direction of shearing. In many historical rock joint shear strength criteria, the effect of a joint's roughness on the joint shear strength is described based on analysis of only a single profile in the direction of shearing. More recent studies have observed that the distribution of sheared area on a joint surface during shear is significantly affected by the...