• Structural Engineering and Mechanics
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• v.43 no.4
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• pp.503-526
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• 2012

Pounding between closely located adjacent buildings is a serious issue of dense cities in the earthquake prone areas. Seismic responses of adjacent buildings subjected to earthquake induced pounding are numerically studied in this paper. The adjacent buildings are modeled as the lumped mass shear buildings subjected to earthquake acceleration and the pounding forces are modeled as the Kelvin contact force model. The Kelvin model is activated when the separation gap is closed and the buildings pound together. Characteristics of the Kelvin model are extensively explored and a new procedure is proposed to determine its stiffness. The developed model is solved numerically and a SDOF pounding case as well as a MDOF pounding case of multistory adjacent buildings are elaborated and discussed. Effects of different separation gaps, building heights and earthquake excitations on the seismic responses of adjacent buildings are obtained. Results show that the seismic responses of adjacent buildings are affected negatively by the pounding. More stories pound together and pounding is more intense if the separation gap is smaller. When the height of buildings differs significantly, the taller building is almost unaffected while the shorter building is affected detrimentally. Finally, the buildings should be analyzed case by case considering the potential earthquake excitation in the area.

• Journal of Korean Association for Spatial Structures
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• v.12 no.4
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• pp.99-108
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• 2012

In recently, sky-bridge are often applied to high-rised adjacent buildings for pedestrian bridge. the seisnic response control of adjacent buildings have been studied and magneto-rheological(MR) fluid dampers have been applied to seismic response control. In this study, vibration control effect of the MR damper connected adjacent buildings has been investigated. Adjacent building structures with different natural frequencies were used as example structures. Two typed of control methods, displacement based or velocity based, are applied to determinate control force of MR damper. In this numerical analysis, it has been shown that displacement-based control algorithm is more effective than velocity-based control algorithm for seismic response control of adjacent buildings. And, when displacement-based control method is applied to control of adjacent buildings, the control of building occurred large displacement is more efficient in reducing the seismic response.

• Earthquakes and Structures
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• v.16 no.6
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• pp.715-726
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• 2019

Several municipal seismic vulnerability investigations have been identified pounding of adjacent structures as one of the main hazards due to the constrained separation distance between adjacent buildings. Consequently, an assessment of the seismic pounding risk of buildings is superficial in future adjustment of design code provisions for buildings. The seismic lateral oscillation of adjacent buildings with eccentric alignment is partly restrained, and therefore a torsional response demand is induced in the building under earthquake excitation due to eccentric pounding. In this paper, the influence of the eccentric seismic pounding on the design demands for adjacent symmetric buildings with eccentric alignment is presented. A mathematical simulation is formulated to evaluate the eccentric pounding effects on the seismic design demands of adjacent buildings, where the seismic response analysis of adjacent buildings in series during collisions is investigated for various design parameters that include number of stories; in-plan alignment configurations, and then compared with that for no-pounding case. According to the herein outcomes, the effects of seismic pounding severity is mainly depending on characteristics of vibrations of the adjacent buildings and on the characteristics of input ground motions as well. The position of the building wherever exterior or interior alignment also, influences the seismic pounding severity as the effect of exposed direction from one or two sides. The response of acceleration and the shear force demands appear to be greater in case of adjacent buildings as seismic pounding at different levels of stories, than that in case of no-pounding buildings. The results confirm that torsional oscillations due to eccentric pounding play a significant role in the overall pounding-involved response of symmetric buildings under earthquake excitation due to horizontal eccentric alignment.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1293-1309
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• 2015

3D two adjacent buildings with different heights founded in different kinds of soil connected with viscous dampers groups, with especial arrangement in plane, were investigated. Soil structure interaction for three different kinds of soil (stiff, medium and soft) were modeled as 3D Winkler model to give the realistic behavior of adjacent buildings connected with viscous dampers under various earthquake excitations taking in the account the effect of different kinds of soil beneath the buildings, using SAP2000n to model the whole system. A range of soil properties and soil damping characteristics are chosen which gives broad picture of connected structures system behavior resulted from the influence soil-structure interaction. Its conclusion that the response of connected structures system founded on soft soil are more critical than those founded on stiff soil. The behavior of connected structures is different from those with fixed base bigger by nearly 20%, and the efficiency of viscous dampers connecting the two adjacent buildings is reduced by nearly 25% less than those founded on stiff soil.

• Journal of Korean Association for Spatial Structures
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• v.14 no.3
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• pp.75-84
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• 2014

When adjacent tall buildings experience earthquake excitation, structural pounding may happen. In order to mitigate seismic pounding damage to adjacent structures, many studies have been done to date. Tuned mass dampers (TMD) are widely used for reduction of dynamic responses of building structures subjected to earthquake excitations. If a TMD is shared between adjacent buildings and it shows good control performance, it will be effective and economic means to reduce seismic responses of adjacent structures. In this study, control performance of a shared tuned mass damper (STMD) for seismic response reduction of adjacent buildings has been evaluated. For this purpose, two 8-story example buildings were used and multi-objective genetic algorithms has been employed for optimal design of the stiffness and damping parameters of the STMD. Based on numerical analyses, it has been shown that a STMD can effectively control dynamic responses and reduce the effect of pounding between adjacent buildings subjected to earthquake excitations in comparison with a traditional TMD.

• Earthquakes and Structures
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• v.20 no.1
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• pp.55-70
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• 2021

In urban cities, buildings were built in the neighborhood, these buildings influence each other through structure-soilstructure interaction (SSSI) and seismic pounding due to limited separation distance in-between. Generally, the effects of the interaction between soil and structure are disregarded during seismic design and analysis of superstructure. However, the system of soil-base adversely changes structural behavior and response demands. Thus, the vibration characteristics plus the seismic response of a building are not able to be independent of those in adjacent buildings. The interaction between structure, soil, and structure investigates the action of the attendance of adjacent buildings to the others by the interaction effect of the sub-soil under dynamic disturbances. The main purpose of this research is to analyze the effects of SSSI and seismic pounding on the behavior of adjacent buildings. The response of a single structure or two adjacent structures with shallow raft base lying on soft soil are studied. Three dimensions finite element models are developed to investigate the effects of pounding; gap distance; conditions of soil; stories number; a mass of adjacent building and ground excitation frequency on the seismic responses and vibration characteristics of the structures. The variation in the story displacement, story shear, and story moment responses demands are studied to evaluate the presence effect of the adjacent buildings. Numerical results acquired using conditions of soil models are compared with the condition of fixed support and adjacent building models to a single building model. The peak responses of story displacement, story moment, and story shear are studied.

• Steel and Composite Structures
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• v.28 no.3
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• pp.289-308
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• 2018

Numerous urban seismic vulnerability studies have recognized pounding as one of the main risks due to the restricted separation distance between neighboring structures. The pounding effects on the adjacent buildings could extend from slight non-structural to serious structural damage that could even head to a total collapse of buildings. Therefore, an assessment of the seismic pounding hazard to the adjacent buildings is superficial in future building code calibrations. Thus, this study targets are to draw useful recommendations and set up guidelines for potential pounding damage evaluation for code calibration through a numerical simulation approach for the evaluation of the pounding risks on adjacent buildings. A numerical simulation is formulated to estimate the seismic pounding effects on the seismic response demands of adjacent buildings for different design parameters that include: number of stories, separation distances; alignment configurations, and then compared with nominal model without pounding. Based on the obtained results, it has been concluded that the severity of the pounding effects depends on the dynamic characteristics of the adjacent buildings and the input excitation characteristics, and whether the building is exposed to one or two-sided impacts. Seismic pounding among adjacent buildings produces greater acceleration and shear force response demands at different story levels compared to the no pounding case response demands.

• Structural Engineering and Mechanics
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• v.83 no.2
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• pp.153-166
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• 2022

Structural pounding due to strong seismic excitations can result in severe damage or even collapse of colliding structures. Many researchers focused on studying the mutual pounding between two adjacent structures while very few researches were concerned with the pounding of a series of structures. This paper aims to study the pounding effect on a series of four buildings having different natural frequencies. The paper also investigates the effect of different arrangements of the four buildings on their pounding response. For this, a mathematical model was constructed using Matlab code where, pounding was modeled using a contact force-based approach. A Non-Linear viscoelastic (Hertzdamp) contact element was used and activated only during the approach period of collision. The mathematical model was validated by comparing its prediction versus experimental results on three adjacent buildings. Then the model was used to study the pounding between four adjacent structures arranged in different sequences according to their natural frequencies. The results revealed that increasing the gap distance generally led to decrease the peak responses of the towers. Such response is somehow different from that predicted earlier by the authors for the case of three adjacent buildings. Moreover, the arrangement of towers has a significant effect on their pounding response. Significant difference between the natural frequencies of adjacent structures increases the pounding forces especially when the more flexible buildings are located at the outer edge of the series. The study points out the need for further researches on buildings in series to gain a better understanding of such complex phenomena.

• Earthquakes and Structures
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• v.24 no.3
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• pp.165-181
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• 2023

The effectiveness of fluid viscous dampers (FVDs) on dynamic response mitigation of coupled two adjacent structures was investigated, considering soil-structure interaction (SSI) effects under earthquake excitation. A numerical procedure was employed to evaluate system response. The finite elements were used for the numerical treatment of the adjacent buildings and soil region. Viscous boundary conditions were used as special non-reflecting boundaries on the edges of finite soil region. According to the results, the FVDs were found to be very effective for dynamic response mitigation of the adjacent buildings, even if considering the soil medium. The results showed that the most affecting parameter on the system response was found to be soil type. It was also concluded that when adjacent structures coupled by FVDs, the maximum values of the roof displacements, the base shear forces, and the base bending moments could decrease up to around 50%. Changing in lateral stiffness of the one building has minor effects on the effectiveness of viscous dampers.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.101-110
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• 2011

Many researchers have attempted to apply semi-active control systems in the civil engineering structures. Recently, magneto-rheological(MR) fluid dampers have been developed. This MR damper is one of semi-active dampers as a new class of smart dampers. This paper discusses the application of MR damper for seismic response control of adjacent buildings subjected to earthquake. Here, a controllable damping force of MR damper that is installed between adjacent buildings is applied to seismic response control. A hybrid model combines skyhook and groundhook control algorithm so that the benefits of each can be combined together. In this paper, hybrid control model are applied to the multi degree of freedom system representative of buildings in order to reduce seismic response of adjacent buildings. And the performance of hybrid control model is compared with that of others. It was demonstrated that hybrid control model or adjacent buildings with MR damper was effective for seismic response control of two adjacent buildings reciprocally.