Numerical simulations and parametric studies have been used to investigate the influence of potential poundings of seismically isolated buildings with adjacent structures on the effectiveness of seismic isolation. Poundings are assumed to occur at the isolation level between the seismically isolated building and the surrounding moat wall. After assessing some common force-based impact models, a variation of the linear viscoelastic impact model is proposed to avoid tensile impact forces during detachment, while enabling the consideration of permanent plastic deformations at the vicinity of the impact. A large number of numerical simulations of seismically isolated buildings with different characteristics have been conducted under six earthquake excitations in order to investigate the influence of various design parameters and conditions on the peak floor accelerations and interstorey deflections during poundings. The numerical simulations demonstrate that poundings may substantially increase floor accelerations, especially at the base floor where impacts occur. Higher modes of vibration are excided during poundings, increasing the interstorey deflections, instead of retaining an almost rigid-body motion of the superstructure, which is aimed with seismic isolation. Impact stiffness seems to affect significantly the acceleration response at the isolation level, while the displacement response is more insensitive to the variation of the impact stiffness. Finally, the results indicate that providing excessive flexibility at the isolation system to minimize the floor accelerations may lead to a building vulnerable to poundings, if the available seismic gap is limited.

SUMMARY The response of multi‐storey structures can be controlled under earthquake actions by installing seismic isolators at various storey levels. By vertically distributing isolation devices at various elevations, the designer is provided with numerous options to appropriately adjust the seismic performance of a building. However, introducing seismic isolators at various storey levels is not a straightforward task, as it may lead to favourable or unfavourable structural behaviour depending on a large number of factors. As a consequence, a rather chaotic decision space of seismic isolation configurations arises, within which a favourable solution needs to be located. The search for favourable isolators' configurations is formulated in this work as a single‐objective optimization task. The aim of the optimization process is to minimize the maximum floor acceleration of the building under consideration, while constraints are specified to control the maximum interstorey drift, the maximum base displacement and the total seismic isolation cost. A genetic algorithm is implemented to perform this optimization task, which selectively introduces seismic isolators at various elevations, in order to identify the optimal configuration for the isolators satisfying the pre‐specified constraints. This way, optimized earthquake response of multi‐storey buildings can be obtained. The effectiveness of the proposed optimization procedure in the design of a seismically isolated structure is demonstrated in a numerical study using time‐history analyses of a typical six‐storey building. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARYA new earthquake resistant structural system for multi-storey frame structures, based on a dual function of its bracing components, is developed. This consists of a hysteretic damper device and a cross-bracing mechanism with a kinetic closed circuit, working only in tension, so that cable members can be used for this purpose. Solutions are presented regarding the connections' design of three types of structural frame system, that are concerned throughout the study: braced moment free frame, braced moment resisting frame with moment free supports, and with moment resisting supports. The dynamic behaviour of the system is investigated on the basis of an SDOF model, and based on the response spectra method an approximate design approach of the controlled structures is shown. From the time history analysis of the structural systems for the El-Centro earthquake the areas of appropriate sti ness relations of the frames to the hysteretic dampers and the cable braces are deduced, so that the energy dissipation of the system may be controlled by the damper-cable bracing mechanism. Based on the results of these studies, a predesign approach is developed for the implementation of the control system in frame structures.

Supported through technological advances, the concept of kinetic architecture is internationally increasingly acknowledged in the past years in the development of adaptable buildings as to differing functional requirements, or external loading conditions. Most decisive factor is the structure in terms of materials and geometrical configurations, and the control system integrated within. Based on general principles of tensegrity structures, a hybrid system has been developed that consists of continuous hinge connected compression members, strengthened by an internal system of struts and continuous cable diagonals with closed loop.The kinetic mechanism is achieved through alteration of the cables length and the respective relative inclination of any adjacent compression members. In this way the transformability of the system arises primarily from the inherent integrative composition and dual capabilities of its members. Following the construction design of the prototype structure, the interactive development, as regards geometric properties and structural configurations, is presented analytically, as based on a parametricassociative design approach applied. Along this line, the specific syntax of structural development and simulation through parametric design is suggested to support in real terms the control design of the innovative structure in an integrated interactive context.

Shape-control in an architectural context is expected to provide unique opportunities for buildings with enhanced functionality, flexibility, energy performance, and occupants comfort. An architectural concept is proposed which consists of a parallel arrangement of planar n-bar mechanisms formulating its skeleton structure and a membrane material stretched over it to define the building envelope. Overall shape changes involve coordinated motion of the individual planar mechanisms. Each linkage is equipped with one motion actuator as well as brakes installed on every joint. Reconfigurations of the building are based on the “effective 4-bar (E4B)” concept allowing stepwise adjustments. Each intermediate step involves the selective locking of (n − 4) joints on each closed-loop linkage effectively reducing it to a single degrees-of-freedom (DOF) 4-bar mechanism, the configuration of which can be adjusted using the available motion actuator. A reconfiguration of the mechanism can be realized through alternative control sequences and an optimal one can be selected based on specific criteria. The paper reports the fundamental design and control concepts. A simulation and an experimental study are presented to demonstrate the implementation of the general reconfiguration approach and examine relevant issues.