In this study, non-linear behavior of diagonally stiffened steel plate shear walls as a seismic resisting system has been investigated, and theoretical formulas for estimating shear strength capacity of the system have been proposed. Several validated analytical finite element models of steel shear walls with various stiffener dimensions are generated to verify and compare the analytical and theoretical outcomes. Non-linear transient analysis under monotonic loading are carried out and the pushover curves of the models are obtained. It is observed that the diagonal stiffeners have been able to reduce the buckling effects of the infill steel plate, and they have increased the elastic shear buckling strength and the ultimate shear capacity of the system in comparison with the un-stiffened thin steel plate shear walls, and there are good agreements between the propounded theoretical method and the analytical results.

To evaluate the shear performance of deep beams reinforced with Glass Fiber Reinforced Polymer (GFRP) plate, a test was conducted on 8 specimens. Test variables included reinforcement, shear span ratio, area of reinforcement, and effective depth. The effects of the test parameters on the shear strength of the test specimens were evaluated. The test result showed that smaller span ratio leads to larger shear strength, and that increase in the area of reinforcement and effective length increased shear strength. All test results were compared with strut-and-tie models suggested by ACI 318 and CSA.

In general, shear wall design is based on flexural ductility. In this design approach, behavior of the shear walls is more similar to a cantilever beam with significant bending moment at its base. In such systems, the main input energy dissipation during seismic events happens at the base of the shear wall. In this paper, in order to improve the behavior of these important lateral resisting mechanism in structural systems, the possibility of dual type behavior (flexural and shear) were investigated. At first, the potential of this approach in improving the behavior of shear walls has been examined in a simplified structural model. Later, three types of shear walls including slit walls, shear walls with opening and frame-wall systems have been studied. The results show the capability of dual ductility modes of behavior in all three systems. Energy dissipation dispersion in these systems is better than the ordinary shear walls. Among the dual ductility systems, the frame-wall system has shown a superior performance compared with that of the two other systems.

The presence of numerous discontinuity planes in rock mass structure would decrease strength, increase deformability of the rock mass and make the mechanical behavior of the rock mass much more complex. The effect of strength, deformation and conductivity characteristics of discontinuities on physical properties of rock mass is even more important than characteristics of the intact rock itself. Because information is lacking, the transition from peak to residual values now often assumes to decrease either linearly or exponentially when the joints exhibit strain-softening behavior. Three types of artificial joints with angle i= 15, i=30 i=40 degree asperity under repeated direct shearing are performed in this experimental research. The progressive failure mechanism and strength degradation of rock joints after peak strength are monitored during shearing. The progressive degrading of shear strength parameter or index is examined according to two strength criteria (Barton and Patton). The JRC (joint roughness coefficient) value for a given profile is estimated by fractal dimension.

The effects of cementation and the physical properties of grains on the shear behavior of grouted sands are investigated in this paper. The consolidated-undrained triaxial shear behavior of three grouted carbonate sands with different physical properties, including particle size distribution, particle shape and void ratio, was studied. Two sands were obtained from the north shores of the Persian Gulf, south of Iran, called Hormoz and Kish islands sands, and one sand was obtained from the south beaches of England and called Rock beach sand. The selected sands were grouted using a chemical grout of sodium silicate and tested after one month of curing. Test results showed that the effect of bonding on the shear behavior and strength depends on the bond strength and confining pressure. In addition, the shear behavior, yield strength and shear strength of grouted sands under constant conditions, including the initial relative density, bonds strength, confining pressure and loading, were affected by the physical properties of the sands. Furthermore, the parameters of the Mohr-Coulomb shear strength failure envelope, including the cohesion and internal friction angle of grouted sands under constant conditions, were affected by the physical properties and structure of the soils.

Steel plate shear walls have been noticed in recently three decades to considering lateral loads of earthquake and wind, in high rise buildings behavior of this system resembles a steel plate girder used in a vertical cantilever application. The columns fulfill the function of the flanges of the vertical girder, while the horizontal floor beams act as web stiffeners. Before acceptance of the idea to utilizing post-buckling strength of infill steel plate, stiffened walls with heavy stiffeners were used to preventing infill steel plate buckling but after acceptance of this idea, unstiffened walls replaced with stiffened walls. However in seismic rehabilitation of existing buildings and retrofitting the structures, which are more in attention recently or in place which wall has an opening using stiffeners has a high importance. In this research influence of X, K, V, inverse V and V-H shapes of the stiffeners on steel plate shear walls have been studied. Results of finite element analysis show that X shape stiffener in compare with other diagonal stiffeners including K, inverse V and V shape especially V-H shape stiffener, have more effective influence in increasing yield and ultimate loads and energy absorption capacity of panel. Also unlike plate girders which for doing economic design stiffener is used in steel plat shear wall systems, it is better using unstiffened panel.

Introduction Now cities are not comparable to the past for many problems such as air and sound pollution of factories and vehicles. Some natural systems such as parks help to keep the stability of cities and improve the life quality of urbanites. Privet with the scientific name of Ligustrum Ovalifolium is the evergreen plant, and widely cultivated at all of the parks in Iran. Privet stems are pruned by manual or gasoline-powered hedge trimmer. The knowing of the cutting properties of privet stalk have important role in the design and fabricate of privet pruning machine. A series of laboratory test was conducted to measure the shear force, shear consumption energy and shear strength of stem internodes of privet stalk under quasi-static and impact cutting at different loading rate, different internode position and moisture level 58% wet base. In the quasi-static cutting test, the stalk specimens were cut in the quasi-static process by using a computer aided cutting test apparatus at four loading rates: 5, 10, 15 and 20mm/min and three internode positions: fifth, tenth and fifteenth downward from the terminal bud. In impact test, the stalk specimens were served in impact process by using a cutting test apparatus was designed, fabricated, and calibrated at four loading rates: 1, 2, 3 and 4m/s and three internodes: fifth, tenth and fifteenth. Materials and Methods The study was performed to investigate the effect of quasi-static and impact shear on shear force, shear consumption energy and shear strength. The measured initial moisture content of the samples was 58% on wet base. The privet stalk diameter decreases towards to the top of the plant stalks. Thus, the stalks equally was divided into three regions downward from the terminal bud: (a) fifth internode, (b) tenth internode and (c) fifteenth internode. The quasi-static tests were conducted using the universal testing machine (SMT-5, SANTAM Co, Iran). The shear tests were carried out at four rates of speeds 5, 10, 15 and 20 mm/min. To determine the shear force of privet stalk, an impact cutting tester was designed, fabricated and calibrated. It was similar to an Izod impact cutting tester for metals. A cutting blade with sharpened angel of 23 degree and oblique angle of 60 degree was attached to end of pendulum's arm. The shear tests were carried out at four rates of blade speeds 1, 2, 3 and 4 m/s. A data acquisition system was attached to pendulum arm and it includes 4 strain gages and a digital indicator to show the real-time shear force. Four strain gages were contacted to each other by Wheatstone bridge circuit and were mounted on two sides of pendulum. After calibration, the impact shear force was applied to the privet samples by releasing the pendulum arm in the testing machine up to the sample failure. The real-time applied force and cutting time were measured by data acquisition system and chronometer. Results and Discussion In quasi-static cutting of the stalk specimens, the analysis of variance (ANOVA) indicated that the loading rate and interaction of loading rate internode position have significant effect on the shear consumption energy and shear strength in probability level of 5% and 1% respectively. However, the effect of internode position on shear force, shear strength and shear consumption energy was significant in 1% probability levels. In impact cutting of the stalk specimens, the analysis of variance showed that, the effect of the loading rate and their interaction of loading rate internode position on the mentioned parameters were significant (P<0. 01) but the effect of internode position on shear force and shear consumption energy was significant in 1% probability levels. The average values of shear force, shear strength and shear consumption energy were deeply decreased with increase in loading rate level from 1 to 4 m/s and internode position from fifteenth internode to fifth internode. Conclusion In quasi-static cutting, the increment proportion of energy consumption at blade velocity of 20mm/min to 5mm/min is about 2. 2 at fifth internode, 2. 6 at tenth internode and 2. 9 at fifteenth internode respectively. Also in quasi-static cutting process, the increment proportion of shear strength at blade velocity of 20 mm/min to 5mm/min is about 1. 5 at fifth internode, 1. 4 at tenth internode and 1. 2 at fifteenth internode respectively. In impact cutting, the reduction proportion of energy consumption at blade velocity of 1m/s to 4m/s is about 1. 44 at fifth internode, 1. 6 at tenth internode and 3 at fifteenth internode respectively. Also in impact cutting process, the reduction proportion of shear strength at blade velocity of 1m/s to 4m/s is about 5. 2 at fifth internode, 29. 4 at tenth internode and 53. 8 at fifteenth internode respectively.

Shear walls are among the most common lateral load resisting systems, which are not recognized as efficient ductile structural components. Using any opening in the wall leads to disperse the inelastic behavior across the height of the wall and employ both flexural and shear ductility capacity of the system at the base and around the openings, respectively. Simple models were utilized to study the role of large openings in inelastic dynamic behavior of shear walls. Despite the constant total input energy, the amount of dissipated energy at the lower part of these walls is decreased to about two-third the value of ordinary shear walls. Consequently, the ductility demand diminished in the plastic hinge at the base and the required reinforcement detailing becomes simpler. However, marginal gains observed in the structural response such as base shear, base moment, inter-story drift and story displacement. Furthermore, to obtain the crack patterns and the ductility of the walls, static inelastic analyses were carried out using accurate finite element models. The results reveal that despite a small reduction in the strength of shear walls with openings, the crack patterns distribute more uniformly, and the ductility increases as the opening becomes larger.

For laterally complex media, it may be more suitable to take a different orientation of the displacement vector of Shear-waves. This may change the sign of several imaginary reflections and conversion coefficients to be used in reservoir characterization and AVO (Amplitude Versus Offset) analysis or modeling. In this new convention the positive direction of the displacement vector of reflected Shear-waves is chosen to the left of ray tangent (in the direction of wave propagation). Therefore, the definition of the displacement vector of shear-waves can be used properly even for very complicated media. Finally the shear-wave dynamic behavior of a reservoir zone can be illustrated for laterally varying structures in terms of the amplitude variation and phase behavior using this new orientation.