Steel and composite shear walls are some effective lateral resisting systems with a steel core. The main advantage of these systems is their deformability, due to the buckling behavior of the steel sheet. Two general methods for benefiting this advantage are using steel-stiffening elements or concrete layers connected to the steel plate by shears connectors. In this research, by studying different behaviors, including the influence of middle beam rigidity, the type of beam to column connection, changes in shear connector's distance, the effect of concrete layer thickness on a composite shear wall, with and without stiffeners and a general behavior of this system against lateral loads, are investigated. In this regard, various models of such walls are analyzed using the Finite Element method.The analytical results show that the stiffened steel shear wall behavior is independent of the middle beam rigidity and the beam column connection type, but, in a steel shear wall without stiffeners, the increase of middle beam rigidity causes a better monotony of stress distribution in the steel sheet. Also, the shear resistance of a composite shear wall depends on the concrete layer thickness and the distance between shears connectors. So, by studying the analytical results, an optimum concrete thickness and, also, a suitable distance between shears connectors, are proposed.

Application of self-centering rocking walls is now widely accepted as a viable alternative to removal of some of the common seismic defects of conventional shear walls including residual drift and significant damage to the base of walls. Despite the different experimental studies on the seismic performance of rocking walls, few numerical models have been developed to predict the seismic response and damage extent of these walls under seismic loading. The main objective of this study was to present a practical method for numerical modeling and damage estimation for nonlinear behavior of post-tensioned (PT) concrete rocking walls when exposed to earthquake excitations. To this end, PERFORM 3D software was utilized to model self-centering rocking walls. The walls were subjected to a set of seven spectrum compatible ground motions at different intensity levels. To ensure the accuracy of the modeling, the numerical results of the nonlinear analysis were compared with the experimental results, and the results showed that the developed model could predict the behavior of the wall during all ground motions with acceptable accuracy. Moreover, in this study, a damage index was employed to estimate the extent of damage in the developed numerical model. Good agreement between the observed damage in the shake table tests and estimated damage in the developed model was observed. The results of this study indicated that the method for modeling the seismic behavior of the rocking wall could appropriately predict the response and damage extent of these walls under earthquake loading.

This article presents a research program on a structure representing a seven-story residential building tested on the shaking table in the NEES [6]. The building was designed using a displacement based capacity approach for a site in Los Angeles resulting design lateral force. The structure is composed of 2 main perpendicular walls connected by slotted connections. The numerical calculations have been made up to failure of the specimen, at the local but also at the global level, using multi-fiber beams. Constitutive laws are based on damage mechanics and plasticity to describe cracking of concrete and the plastic behavior of steel. It is shown that the model is able to describe the global behavior of the structure and qualitatively the distribution of damage at the base of the specimen.

For rubble mound breakwaters, incorporating a berm in the seaward slope can be very effective in reducing wave overtopping and mitigating wave loads acting on the breakwater armor elements. This research aims to investigate the effect of horizontal berm on the seismic response of conventional rubble mound breakwaters, considering various amplitudes and frequencies characterizing seismic loads. Finite element models of conventional rubble mound breakwaters, with and without berm, are developed using Plaxis 2D software for this purpose. Additionally, the stability of rubble mound breakwaters with berms is studied through various numerical models, considering different lengths and height levels of the berm. A comparative analysis of the results shows that rubble mound breakwaters incorporating berms exhibit lower deformation characteristics compared to those without berm. The numerical study results suggest that berms can significantly enhance the stability and reduce displacements of rubble mound breakwaters under seismic loading compared to breakwaters without berm.

Lightweight concrete has been used in the construction industry for many years and by the introduction of modern technologies in the construction industry, this type of concrete has been accounted as one of the powerful and reliable materials in the construction industry. The density of lightweight concrete is about 0. 56 that of the ordinary concrete. This type of concrete is commonly used as a flooring material in buildings. Thus there is possibility of its corrosion in different climatic conditions. In the present research, we would investigate the compressive strength and durability of the lightweight concrete in the acid environment, so that by specifying the corrosion rate, one could have a better understanding of the behavior of these concretes. For making the lightweight concrete in the present research use has been made of pumice aggregate in the mix design, and the acid used is 1M sulfuric acid. Also, the effect of adding two types of Nanomaterials i. e., Nano silica and Nano clay on the concrete behavior is assessed. The results have shown that in case of keeping the specimens of lightweight concrete in the acid environment for 90 days, their weight reaches 0. 56 that of the ordinary specimens. The results of the current research have shown that the use of Nano silica and Nano lime per 10 wt% of cement could result in the increased compressive strength of the lightweight concrete. So that the concrete compressive strength per 10 wt% of Nano lime increases by 1. 43%. On the other hand, the concrete durability in the acid solutions reaches the maximum value per addition of 5% Nano silica and 5% Nano lime, and has lost a lower percentage of its weight.

The present work aims to study the seismic performance of exterior shear wall-slab joint with non-conventional reinforcement detailing. Four joint sub assemblages were tested under reverse cyclic loading applied at the end of the slab. The specimens were sorted into two types based on the joint reinforcement detailing. Type 1 model comprises of two joint assemblages having joint detailing as per the conventional detailing of slab bars at the joint.The second set of models (Type 2) comprises of two specimens having additional cross bracing reinforcements for the joints detailed as per the provisions given for beam–column joint in IS 13920: 1993. Analytical investigations were employed to compare the experimental results. The experimental results and analytical studies indicate that additional cross bracing reinforcements improves the seismic performance.

During an earthquake, a wall is subjected to a three-dimensional acceleration field and undergoes simultaneous in-plane and out-of-plane loading. It is often noted that in the field of brittle material strength, presence of one type of loading on a structural element affects the strength of that element against another type of loading. Considerable number of numerical and experimental studies, carried out to-date to investigate the behaviour of masonry walls under seismic loading, have either considered the in-plane response or the out-of-plane response of the wall separately without due consideration for any possible interaction between the two responses. In this paper, the results of a series of tests with different levels of simultaneous in-plane shear and out-of-plane bending actions on small brick walls constructed with standard high strength mortar are presented. The tests results indicate noticeable interaction between the in-plane shear and out-of-plane bending strengths of brick walls. The interaction curve appears to followa circular trend.

It is known that large inelastic deformation limits of individual members allow entire structures to endorse severe ground motion while dissipating significant levels of seismic energy. Plastic hinge formations associated with lateral displacement excursions is favored in beams and girders rather than in columns to ensure that the overall structural integrity is not compromised. Plastic hinges can occur in columns, however, particularly at the base of multistory frames and bridges where incurred, damage acts to dampen seismic forces considerably. Ductile behaviour is hence essential at these crucial sites to prevent complete structural collapse under sustained loading. The structural response during earthquakes have indicated that the majority of the column failures was caused by high shear stresses, insufficient transverse reinforcement rendering those members ineffective at dissipating seismic energy and inadequate ductility rapidly leading to failure. Typical procedures to compensate for the deficiencies involve external retrofitting of these columns. Recent research works 1,2) have indicated that ferrocement jacketing may be used as an alternative technique to strengthen RC columns with inadequate shear strength. The present objective is to complement the earlier work of the authors 3,4,5), on the use of ferrocement jackets for seismic retrofit of non-ductile reinforced concrete columns with inadequate shear strength. The response of R.C and ferrocement retrofitted columns to seismic loading was examined under three different axial load ratios.