جستجوی مقالات مرتبط با کلیدواژه « اندرکنش خاک و سازه » در نشریات گروه « فنی و مهندسی »

In current research, structure collapse of fourstore concrete bending frame on sand soil was considered with noting uncertainty of soil parameters. The structure was lumped using plastic hinge and soil and structure interaction was modeled using BNWF method. First, structure was reviewed with or without soil and structure interaction using nonlinear static analyses and incremental dynamic analyses (IDA). Then uncertainty of soil parameters in soil and structure interaction was considered. Cohesion, internal friction angle, unit weight, shear modulus, and soil Poisson ratio was noted with considering probable distribution and considering consistence between these as uncertainty of soil parameters. Latin Hypercube Sampling (LHS) method and Choleski decomposition were used to manufacture and simulate dependent random variables and manufacture random variables. After manufacturing 26 structure samples for uncertainty of soil parameters, fragility curve in sample collapse level was compared with base fragility curve. 20 far-field records were used for incremental dynamic analyses and obtaining the fragility curve. Screening method was used to define participation percentage of uncertainty of soil parameters in collapse response and structure natural periods. Then, response surface method was used to predict structure response functions. At ultimate, the result presented that considering soil and structure interaction increases the natural periods of structure first mode. Noting the nonlinear static analyses, considering soil and structure interaction decreases the structure base hardness and shear and increases the roof relative displacement. All statistic percentiles of structure IDA curves are lower than fixed base mode with considering soil and structure interaction and present that soil and structure interaction causes structure to collapse in lower spectral acceleration. Comparison of fragility curve in two cases presented soil and structure interaction increases collapse probable. All fragility curves of samples manufactured in investigating uncertainty of soil parameters effect on structure collapse are higher than fragility curve of the case in which structure is modeled hinged at base. This presents that uncertainty of soil parameters increases structure collapse. Also, sample fragility curves are 10.2% and 8.6% greater than fixed base mode at probable collapse of statistic percentiles 16% and 84%. Comparing statistic features of 26 manufactured sample responses for uncertain soil parameters with the case in which structure is fixed at base presents that all manufactured samples presented an increase in structure first mode periodic time and maximum drift between stores and a decrease in structure collapse capacitance and structure collapse drift is more sensitive to soil parameter changes. After orienting structure responses in 26 manufactured samples for uncertainties based on incremental structure first mode periodic time, structure collapse drift increased, and structure capacitance decreased in an increase on structure periodic time. Soil shear modulus has the highest and soil cohesion has the lowest participation percentage of uncertainty of soil parameters in structure first mode periodic time. Soil internal friction angle and soil shear modulus have the lowest participation percentage of uncertainty of soil parameters in responding to structure collapse drift. Soil shear modulus has the largest and soil cohesion and soil Poisson ratio have the lowest participation percentage of uncertainty of soil parameters in structure collapse capacitance response.

The increasing construction of high-rise structures in cities and the placement of buildings on soils with different layers show the need for engineers to pay attention to the effect of different conditions of soil layers on the seismic response of structures. In this study, after validating the 3D numerical model using the previous shaking table test, the effect of soil layering on the seismic response of resistant concrete buildings has been investigated by considering the soil-structure interaction (SSI). Using Abaqus finite element software, a set of numerical modeling for a 15-story building placed on layered soil with different values of shear wave velocity has been simulated. Nonlinear dynamic analysis under seismic motion has been performed in a direct way and the results have been compared and discussed in terms of maximum lateral deflection, shear force, and inter-story drifts of floors. The results showed that the deeper the soil layer with the lower shear wave speed and the closer it is to the ground surface, the higher the values of lateral deflection and shear force and the inter-story drifts. Also, according to the results, soil layering has a major contribution to the seismic response of buildings by considering SSI, and considering the soil-structure interaction ensures the safe and economical design of structures.

Given the importance of surface water reservoirs and their application in various industries, comprehensive knowledge of the seismic behaviour of these facilities is required. In such structures, due to soil structure interaction and fluid structures, seismic behaviour without the help of software based on the numerical solution is not possible. Therefore, finite element software, Abaqus, is required. In this paper, a three-dimensional model of a solid rectangular surface tank and underlying soil was considered in addition to the effects of SSI and FSI. For a closer examination, the Drucker Prager nonlinear model was used to describe the behaviour of the soil and for modelling the interaction of water and reservoir to the normal behaviour Hard Contact was used; and for soil-structure interaction, Frictionless behaviour, the theory of Columbus, was used. By using sensitivity analysis, the sensitivity for the dynamic interaction parameters was obtained, and then the results were compared with the results of Iranian publication number 123. The results showed that the soil beneath the tank and soil-structure interaction had a great impact on the seismic behaviour of surface reservoirs. Furthermore, the effect of sloshing water was highly dependent on the intensity and frequency of the seismic load. Because the behaviour of water in the high-frequency earthquake is different, the low-frequency response often tends to increase the reservoir's behaviour.

The presence of liquefaction in the soil has a great impact on the condition of the structures built in that area; therefore, studying and evaluating liquefaction is of great importance. Liquefaction of the sand lens can cause changes in the force and shape of the tunnel lining. These issues have been evaluated and investigated in this article. Asymmetric deformations and distortions in the tunnel lining lead to an increase in the ratio of dynamic torque to static torque and distance to diameter. The presence of this phenomenon causes changes in the state of effective stresses, pore water pressure, and settlement. In this thesis, the effect of the sand lens around the tunnel is investigated. Soil-structure interaction is also considered between the tunnel and the sand lens. To put it more simply, a sand lens is a piece of soil in the environment that has high liquefaction properties, so its investigation and evaluation is an important matter that has not been extensively studied so far. Estimation of peripheral and structural soil parameters in tunnel lining always requires software simulation and bulky and time-consuming studies. Providing a method to be able to present these parameters with appropriate accuracy and small computational effort in the fastest possible time has always been an engineering challenge. Therefore, the present study aims to present a machine learning-based method to predict some important properties such as liquefaction event, maximum bending stress of tunnel cover, settlement of subsurface tunnel, and pore water pressure under near- and far-field earthquakes. Hence, first, the three-dimensional finite-difference software with parameters such as soil-structure interaction between tunnel cover and sand lens has been used to simulate the tunnel cover model exposed to ground stimuli. Mohr-Coulomb and Finn models have also been used to consider clay sediment and sand lens liquefaction evaluation, respectively. Then, an extreme learning machine (ELM) is used to predict and estimate the quantities mentioned. The main purpose of this study is to introduce a new method using extreme learning machine to predict some important characteristics such as liquefaction event, maximum bending stress, settlement, and pore water pressure. The results of the studies indicate the proper performance and accuracy of the proposed method in estimating the mentioned parameters so that in the worst case, the estimation error was less than 6%. Also in this study, the effect of a liquefiable sand lens in a non-fluidic environment with different seismic waves and the results of the high influence of bending moment in the tunnel lining, effective stress, pore water pressure and the settlement along the axis of the tunnel in the presence of sand lens has been evaluated. The results demonstrate the great influence of the presence of the sand lens in bending moment parameters in the tunnel lining, effective stress, pore water pressure, and settlement along the tunnel axis. In the final part of the study, all the results obtained from the software are compared with the machine learning outcomes. Also, in the presence of a sand lens, the ratio of bending moment to the state without of sand lens in some cases is over 50%, which is a very significant value, and the maximum settlement occurred in places close to the tunnel axis.

In this research, the experimental investigation of the inertial interaction of soil-pile raft structure has been conducted for slender structures supported by the combined pile-raft foundation with emphasis on the new concept of design method (performance-based design). Most of the former studies based on this concept have focused on the surface foundation, where the surface foundation's rocking motion acts as a source of energy dissipation to protect the superstructure. Meanwhile, less attention has been paid to the surface foundation combined with piles (Combined pile-raft foundation) as an economic support system for high-rise and heavy structures. Mainly, the focus of optimizing these foundations through parametric analysis has been on variables such as pile arrangement and pile length for vertical static loading. When the heavy structures are subjected to the lateral load caused by the earthquake, the foundation experiences significant inertial moments. Thus, the nonlinear behavior of the foundation is not far from expected. The present research intends to examine the rocking behavior of combined pile-raft foundations as the foundation of slender structures. Evaluating the response of the superstructure and its possible benefit from the nonlinear behavior of the foundation is the principal goal of this research. In this regard, using experimental models, some characteristics of combined pile-raft foundations, such as the arrangement of piles and the relative length of the piles, have been investigated on the response of the superstructure. Three physical models were constructed in the laboratory. Each model contained a single degree of freedom superstructure supported by a floating pile raft foundation in sandy soil. Two characteristics were considered for evaluating pile raft characteristics: pile configuration and pile length ratio. The superstructure was identical in all three physical models. An experimental procedure based on forced vibration tests was presented to assess the dynamic response of the models at different levels of foundation nonlinearity. According to the experimental measurements, the nonlinear behavior of the foundation has a significant role in the response of the superstructure. Dynamic demand reduction as well as drift reduction are the two most important factors that benefit the superstructure from foundation nonlinearity. Accordingly, the dynamic behavior of the models is divided into two individual phases. Also, comparing the results of the models showed that the arrangement of piles and the relative length of the piles in the combined pile-raft foundation have a significant impact on superstructure response.

Turning to clean energy is inevitable, among which wind energy is one of the most common and available. Theuse of wind energy due to its known advantages over other renewable energies has caused the technology of windturbines to grow more, and this has led to the increase in the capacity of wind turbines and the commercialization oflarger sizes. By increasing the capacity of wind turbines, the size of the rotor and consequently the height of thetower necessarily increase. Therefore, the design of wind turbine towers more goes complex day by day, and mustbe done specifically on a case-by-case basis. For this purpose, wind turbines should be modeled completely with alldetails. One of the most expensive parts of wind turbines is its tower. Considering the whole applied forces anddesign criteria and fatigue base on the regulations and guidelines is necessary to achieve a safe performance. Inaddition to these factors, in seismic prone areas the dynamic earthquake forces should be considered in analysis anddesign of towers. Therefore, in this study, we have tried to study the seismic behavior of a real tower model incomparison with other dynamic forces, in order to obtain the amount and manner of effect of each force. Standardsgenerally specify design load combinations for ultimate load and fatigue load analyses. The speed of 11 m/s is thespeed at which, according to the power generation diagram of the studied turbine, the speed of the turbine reaches itsmaximum power, and it is assumed that the turbine will be installed in a site where the wind will be at this speedmost of the time, and the probability of earthquake occurrence at this speed is more than other modes.Therefore, considering the emphasis on considering the earthquake force in seismic areas along with other forcesacting on the wind turbine in the new versions of the regulations in this field, and the seismicity of Iran, acomparative analysis of seismic load with other forces acting on the wind turbine based on Standard GL, chapter 4,Table 4.3.2 for turbulent wind of 11 m/s, in the state of zero deviation angle for the 2 MW national wind turbine ofIran, with an 80-meter steel tower and a 55-meter 3-bladed rotor, in a complete and practical model, with themodeling of the steel tower structure and concrete foundation and soil layers in the case construction. The commenthas been analyzed and investigated by the dynamic finite element numerical method using Abaqus software.Considering the location of this wind turbine, with soil layers 6 meters deep, the maximum change in the location ofthe tip of the tower by considering the seismic load increased by about 7%, but the significant increase in theequivalent stress at the height of 50 meters of the tower, despite the low depth of soil layers. The lack of significantacceleration of the earthquake from the rock bed to the earth's surface was obtained, amounting to 36%. Therefore,the necessity for simultaneous consideration of earthquake load along with the wind load was well concluded.

Process towers or vertical vessels are among the industrial structures that play a key role in the production process of petroleum products and their derivatives in refineries and oil and gas industries. Due to the vulnerability of these structures in past earthquakes, and the lack of valid regulations and methods for seismic analysis and design of these structures, a case study on a designed and constructed process tower 26.5 meters high, located in Qeshm Island Refinery, has been conducted in this research. Since considering a rigid foundation, without the interaction of soil and structure, may lead to wrong results, in this study, the tower has been modeled in Abaqus finite element software considering soil behavior. The Winkler model used for soil modeling and the seismic behavior of the tower was investigated using pushover and incremental dynamic analysis, and finally, the resulting fragility curve is presented to show the structure's vulnerability at different levels of seismic intensities. In this investigation, the probable failures, including the failure of the body and the skirt, as well as the overturning of the structure, have been investigated. According to the incremental dynamic analysis results, no buckling was observed in the body and the tower's skirt before the tower overturned. The results show that overturning was the predominant failure mode and the probability of this failure mode until PGA=0.1g is approximately equal to zero, and for PGA= 0.35g, this probability is less than 20%. But for rare seismic intensities, the overturning probability is considerable.

This research, investigates the behavior of 3, 5, and 8-story steel structures with medium bending steel frames in four cases without considering interaction (A), considering interaction (B), using damper (C), and in Damper usage mode considering soil and structure interaction (D) and the performance of pal dampers, fragility curve, has been discussed under seven acceleration maps of the near-pulse area. The innovation of the research is in the use of a pal friction damper and considering the effect of soil-structure interaction (SSI) to investigate the dynamic and seismic behavior of low and mid-rise intermediate moment steel.Modeling has been done in ETABS software and Incremental Dynamic Analysis (IDA) by LRFD method in Opensees software.Vulnerability levels introduced in HAZUS MH-MR4 have been used to investigate different failure modes of the models. The studied frames with dampers have been subjected to nonlinear analysis in three damping levels 5%, 10%, and 15%. The obtained results showed that: for the state (B) in short structures, the order of displacement of floors remained almost constant and had no difference compared to state (A); But in case (C) it caused a decrease in the movement of floors and on the other hand in case (D) the movement of floors has been relatively reduced; And the pattern of displacement reduction in different records is different.Also use of a damper has no effect on the amount of base shear of structures, but the amount of base shear has decreased in structures with more floors.

The present paper investigates the effect of soil-structure interaction on the seismic behavior of base-isolated frames under near and far-fault earthquakes. For this purpose, the nonlinear time history results of 1, 4 and 8-story base-isolated frames are compared with corresponding fixed base ones. ABAQUS finite element software is used for numerical modeling on which time history analyzes are performed.

A growing body of evidence suggests that the possibility of nonlinear rocking oscillations can protect the structure from serious damage. One of the potential concerns about this design approach is the magnitude of residual settlement and maximum rotation. Several improvement techniques have been proposed to ameliorate the nonlinear behavior of rocking foundations based on the vertical factor of safety. Rocking systems with a large factor of safety against vertical load are more prone to toppling collapse under severe ground motions. This research explored the effectiveness of using soft walls next to a rocking foundation for mitigating seismic risk. The vital advantage of this improvement technique is that it is a feasible strategy for both new construction and existing structures.
The soil-foundation-structure system has been analyzed using the numerical finite element (FE) method that takes the material and geometric nonlinearities into account. In this case, the nonlinear response mainly involves the interaction between footing uplift and soil failure, which may induce additional (gravitational) aggravating moment (P-Δ effect).
In the first step, a three-dimensional (3D) numerical model has been constructed for the rocking foundation-soil system experiment. In order to verify the accuracy of the simulation, the numerical modeling and the experimental test results have been compared. The results of the centrifuge physical testing conducted were used to validate the numerical simulation. All FE analyses were performed in Abaqus software. This software has been utilized by a number of researchers to study complex soil-foundation–structure interaction phenomena.
Because the initial conditions play an important role in simulating geotechnical problems, a staged analysis procedure has been adopted. In the dynamic analysis stage, an incremental-iterative procedure was used to integrate the equations of motion. The Hilber-Hughes-Taylor algorithm was used to conduct the transient analysis phase. The modified Newton–Raphson method was employed to decrease the calculation cost needed for the great number of degrees of freedom of the model.
Finely refined 3D FE mesh was used to precisely reproduce the mechanism of bearing capacity failure and the rocking behavior. The soil medium and foundation were discretized into eight-node hexahedral continuum elements (C3D8 element type). Two-node linear beam elements were used to model the superstructure (B31 element type). A special surface-to-surface contact formulation between the foundation and soil was used for the realistic simulation of possible uplift and sliding of the foundation. Surface-to-surface contact can calculate contact stresses accurately by reducing the possibility of large-localized penetration of the two surfaces. The properties of the contact element were defined by the interface stiffness in the normal and the tangential directions.
Nonlinear soil behavior was modeled using a kinematic hardening model with the Von Mises failure criterion and associated plastic flow rule. This simplified constitutive model is applicable for the prediction of the undrained behavior of clay as normal pressure independent. In contrast to soil, the behavior of the structure-foundation model is assumed to be linear elastic. A parametric study was carried out to explore the sensitivity of the geometric design variables of the diaphragm wall, such as height and thickness on the behavior of the isolated foundation-soil system.
It should be mentioned that the values of model parameters were determined based on their practical feasibility. The distance of walls has been determined far from the edge of the foundation to avoid static bearing capacity failure.
The results showed that the placement of vertical soft walls next to the foundation could limit the transmitted forces onto the superstructure. This could be lessened the maximum motion of the structure and the following overturning moment of the foundation. Hence, adequate safety margins against toppling collapse could be easily achieved under strong motions.

Evaluating the seismic performance of structures is one of the interests and responsibilities of structural and earthquake engineers. The eccentric bracing system has always been one of the most important and widely used structural systems due to its high strength, stiffness and ductility. These structures are usually designed with horizontal shear and bending links. In this research, using nonlinear dynamic analysis, the seismic response and performance of these structures under near-field records with and without vertical components in addition to considering the effect of soil-structure interaction were investigated. Therefore, three types of frames of 4, 8 and 12 floors were designed and modeled non-linearly using the finite element method in Perform-3D software. Maximum displacement and displacement of roof residue, floor drift and base shear of these structures were selected and studied as engineering demand parameters. The results showed that the structure with horizontal shear link had much better responses than the frame with horizontal bending link. In addition, the effect of soil-structure interaction increased the roof displacement and reduced the base shear on the structure.

The phenomenon of progressive collapse is very important in the management of structures as well as the discussions related to passive defense. Due to the increasing terrorist threats in recent decades and the prevalence of such issues, this phenomenon has become more pronounced. The soil-structure interaction is also a new science in civil engineering. The structure behavior changes due to interactions with the soil and the literature review reveals various methods that have been presented for modelling this phenomenon in recent years. The main problem of the present study is to determine the critical column in the phenomenon of progressive collapse in steel flexural frame by considering the effect of soil-structure interactions with both the direct and indirect methods. The phenomenon of progressive collapse in the present study has been done with the help of column deletion scenario. In addition, the effect of soil-structure interactions has been modeled using the two direct and indirect methods in both Sap and Plaxis software. The two-dimensional steel frames are made for 5, 10, 15 and 20 story structures and are analyzed by the nonlinear static analysis and examined by the corner and middle column removal scenario. Various parameters such as the coefficient of behavior, base shear, displacement of the operating point and top of the node displacement are removed and the expansion of plastic joints are proposed as evaluation indicators. The results of the present study shows that the corner columns are in a more critical condition and the effect of soil-structure interactions in the direct method is much more significant.

Robust estimation of fundamental elastic period of the buildings is essential for obtaining realistic seismic base shear. Seismic design codes provide a variety of equations to calculate the fundamental elastic period of vibration for steel moment frame buildings. The empirical equations are mainly based on the building height and does not take into account the effects of irregularity and soil-structure interaction. In this paper, an empirical predictive equation is developed to estimate the fundamental elastic period of steel moment frames. The predictive equation includes parameters that represent irregularity effects and soil-structure interaction . The database used in this study consists architectural and geotechnical data for 45 building cases. The proposed predictive equation shows satisfactory accuracy. The predicted results are then compared to the values obtained from Iranian 2800 seismic design code, ASCE7-16 and UBC-97. The proposed predictive equation is also verified by 10 fundamental elastic periods obtained from analytical models. The fundamental elastic period obtained using the predictive equations are specifically more accurate for mid- and high-rise buildings compared to seismic design codes. The values obtained from seismic codes are well below the realistic values for the buildings.

One of the most critical parameters in the process of analysis and design of structures is determination of the fundamental period of vibration. The fundamental period depends on the distribution of the mass and stiffness of the structure. However, the building codes propose some empirical equations based on the observed period of real buildings during an earthquake as well as ambient vibration tests. Furthermore, the majority of these proposals do not take into account the presence of infills walls into the structure despite the fact that infill walls increase the stiffness and mass of structure leading to significant changes in the fundamental period numerical value. These equations are usually a function of type and height of the buildings. The different values between the empirical and analytical periods are due to the elimination of non-structural effects in the analytical methods. For this reason, the presence of non-structural elements such as infill panels should be carefully considered. Another effective parameter on the fundamental period is the effect of Soil-Structure Interaction (SSI). It is obvious that soil flexibility increases the fundamental period of the structure. In most of the seismic building codes, the role of the SSI is usually considered beneficial to the structural system under seismic loading since it increases the fundamental period and leads to higher damping of the system. Recent case studies and post-seismic observations suggest that the SSI can be detrimental and neglecting its effects could lead to the unsafe design for both the superstructure and the foundation, especially for the structures located on soft soil. The current research deals with the effect of infill panels on the fundamental period of steel moment resisting (MRF) and eccentrically braced frames (EBF) considering the influence of soil-structure interaction. In this study, all of the buildings designed under gravity and earthquake loading have been evaluated by utilizing 3-D FE modeling incorporating Eigenvalue-analysis to obtain the elastic periods of vibration. For this purpose, the effect of building height, the infill wall panel stiffness, various percentage of infill openings as well as the effect of soil structure interaction in 3, 6, 9, 12, 15 and 18-story 3-D frames were investigated. The studied frames were modeled and analyzed in SeismoStruct software. The calculated values of the fundamental period were compared with those obtained from proposed equation in the seismic code. The results have shown that the number of stories and the soil type are critical parameters that influence the fundamental period of steel frames. Also, it has been found that the height of structures significantly influences the fundamental period. As it is known, in the absence of infill walls, the numerical fundamental periods have generally higher values than those obtained from the empirical formula recommended in building codes such as Iranian Standard No. 2800 and FEMA450 and the other codes. The presence of infill wall leads to a considerable decrease on the fundamental period of steel frames. This decreasing is strongly dependent on the infill wall panel stiffness. In other words, an increase of the infill wall panel stiffness reduces the fundamental period. Also as the infill opening percentage increases, the fundamental period of the structure almost linearly increases. The soil-structure interaction strongly affects the fundamental period of structures. The fundamental period is higher for more flexible soil types. Furthermore, the influence of soil-structure interaction is higher when the infill wall stiffness is higher. Based on the results, one can conclude that the fundamental period of a building cannot be predicted by only using the height of the building. Finally, new equations, which are a function of the selected parameters (building height, modulus of elasticity and the infill wall thickness, infill wall percentage and soil type), are also proposed for predicting the fundamental period of MRF and EBF buildings.

Generally, in the analysis and design of buildings, the foundation is assumed to be rigid and the effect that soil subsidence under the foundation and the flexibility of the foundation may have on the response of the structure is not considered. If the interaction between the structure, the foundation and its supporting soil environment significantly changes the actual behavior of the structure compared to the study of the behavior of the structure alone, and one of the most important issues in soil-structure interaction is the Diagrid Rocking motion of the structure.Examination of the behavior of structures in past earthquakes shows that asymmetric torsion has been one of the causes of severe vulnerabilities. Considering the advantages of modern seismic design methods in which energy dissipation additives such as dampers are used to control the responses in an earthquake, it is possible to control the seismic torsion in the structure. However, recent earthquakes have shown that Steel structures are damaged by earthquakes, making them very difficult and even impossible to repair. For this reason, after relatively severe earthquakes, these buildings have been damaged and destroyed, and in order to reuse the structure, it is necessary to spend a lot of time and money due to the extent of damage to the structure, and this issue creates a new idea to limit damage specific points of the structure.  In this way, buildings can be exploited more quickly by replacing damaged elements. One of the new methods to improve the seismic performance of steel buildings is the use of systems that limit damage to the structure. Among these methods, we can mention systems with rocking motion. In these systems, the main building behaves elastically so that the energy absorption and nonlinear performance occur only in certain parts of the building that have been predicted. Therefore, in this study, a new system has been introduced, using the mechanism of Rocking movement in the shear walls of the structure, transmits damage to the structural fuses and makes the steel structure safe during and after earthquake, and very repairable. The systems used in this research include Diagrid structural system considering the interaction of soil and structure on the foundation and its comparison with Diagrid structural system. To better model this new system, first design post-tensioned cables as well as the exact details of the column connections in ABAQUS software are designed considering the connection dimensions for the 12th story. Then, in SAP2000 software, structural members were designed for 12-story and 16-story diagrid structures with rocking motion. The Results show the high performance of rocking motion on the foundation in reducing the stresses distributed in the diagrid structure. Because with the post-tensioned cables, the displacement of the structure is greatly reduced, while in the diagrid structure, with the movement of the Diagrid, the displacement of the structure is increased by 20%, but due to high attenuation, it has good seismic performance. It has been shown because the number of plastic joints in the LS area has reached less than that. The use of a controlled rocking motion system significantly reduces axial force in structural members by about 30 % and retractable cables in the rocking drive system have an effect more than 70 % in reducing the deformation of the structure and then the flow damper is placed.

Recent earthquakes have shown that, besides the seismic forces, the interaction between faults and structures could cause extensive damage to the surface and underground structures. Field observations showed that the need for design measures and regulations for fault loading due to fault movement in areas with active faults seems necessary. In this study, the three-dimensional finite element model in Abaqus finite element program to study the behaviour of a 9-story steel structure with a moment frame system based on three types of mat foundations, piles group, and diaphragm walls was used on sandy soil. The performance of the structural-foundation system was evaluated taking into account the structural and geotechnical performance goals such as the drift ratio of floor levels, displacement of the foundation and distribution of bending moment and shear force along with the pile and foundation. In this study, the position of the foundation relative to the fault line and the foundation type were considered as key parameters. The results of the analysis showed that the best performance in reducing the ratio of the permanent drift ratio of the floors related to the structure with the diaphragm wall system. This was in the case that the edge of the foundation is tangent to the fault line, this value reaches 1.62%. Also, in most cases, in small amounts of fault movements, the mat foundation system had a smaller difference than the other considered foundation system in this study.

This paper investigates the importance of super-structure modeling in estimating soil’s contribution to the seismic response of soil-structure systems. For this purpose, soil-structure systems with different lateral resisting systems are studied and the values for the main parameters of the system, including parameters determining the soil-structure-interaction (SSI) and the contribution of flexural and shear deformation to the total response of the system are determined. To this end, a one-bay frame with flexural-shear behavior is utilized to model the super-structure in the soil-structure system. In this research, different soil-structure systems are studied using artificial and real acceleration floor responses. The results from investigating different soil-structure systems showed that the proposed method to identify the system can estimate the main parameters of the soil-structure system with acceptable accuracy. Moreover, the results showed that two different systems with different lateral resisting systems and the amount of soil’s contribution can be identified with almost the same floor acceleration responses. For an instant, a moment-frame system located on soft soil with relatively high soil-structure-interaction may have the same floor acceleration responses as a shear-wall located on firm soil with less soil contribution. This observation shows the importance of using more realistic modeling for the super-structure in soil-structure systems to achieve more reliable estimates of soil’s contribution to the system’s response.

In engineering designs, structural analysis is generally performed assuming a rigid base. While introducing the effect of structural substrate flexibility on the response and dynamic properties of structures is important. Introducing different solutions to reduce the response of the structure against dynamic forces is another important issue in engineering designs. In this paper, the passive Pall friction damper system has been used for this purpose. In the researches that have been done so far, various optimization methods have been used for the optimal design of friction dampers, but in most of these methods, the effect of soil-structure interaction has not been considered for friction dampers, while in earthquake soil-structure interactions is important. One of the main objectives of this study is to investigate the effect of soil-structure interaction on the optimization of friction dampers. The actual forces and displacements of a structure due to free-surface seismic movements can be determined by considering the effects of soil-structure interaction. In this regard, in this paper, two-dimensional frames of 4, 8, and 12 floors equipped with dampers were analyzed in nonlinear structural analysis software under seven accelerometers using nonlinear time history method once, considering the effect of soil-structure interaction and introducing 3 Different lateral loading patterns and again without this effect. The results show that considering this issue in terms of cumulative triangular slip load pattern has increased the loss of earthquake input energy.

The effect of liquid tanks shape on their seismic behavior considering fluid – structure and soil – structure interactions has been investigated in the current study. Basically, the tank is a structure used to store different types of fluid, and it is also widely used in refineries, sewage treatment plants and factories in the form of on ground and elevated tanks made from concrete and steel. Regarding the application of the huge dynamic and hydrodynamic loads on a tank at the time of earthquake and the great importance of the structure’s complete function continuity in the critical situations, it is highly important to study its seismic behavior. Among the different analyses, the seismic analysis of the tank is highly important because by investigating the results obtained from this analysis, a useful recognition of the quality of the tank’s behavior at the time of a real earthquake can be obtained. The equivalent rectangular and diamond and ellipticalburiedliquid tanks have been dinamicallyanalyzedunder Elcentro andManjil and Cape earthquakes simoultaneously in the longitudinal and transverse directions and the variousseismicparametersof the system such as thewave maximum height,wallmaximumdrift,concrete maximum tensile stresses and soil maximum compressive stress have been compared with eachother in above mentioned cases in the current research. By study of the computed results of current research, it was revealed that the liquid tanks shape has a considerable effecton their seismic behavior in the same conditions. It also was revealed that the effecttype of variousshapes is not same on the various seismic parameters.