Abstract In this study, the effects of degree directionality on critical seismic performance assessment are investigated from two aspects: bidirectional demand represented by maximum‐direction spectrum and indices obtained nonlinear time‐history analysis. Firstly, typical representations ground motions reviewed compared, in design practices (e.g., ASCE 7‐16, Eurocode8, JRA). Statistical analysis using 83 underlines implication spectrum‐compatible condition that has not been fully considered...

Research shown in this paper is focused on the development of an autonomous semi-active control laws as simplified algorithms for seismic response reduction. The strategy methods to produce desirable hysteretic loops absorb much energy possible by devices. method requires information only device's displacement and velocity. produced herein provide absorption capacity similar those friction dampers, while minimizing disadvantages such residual after strong earthquakes generation...

The angular-mass damper referred herein is a wheel that has concentrated mass on its perimeter. rotational inertia of the employed to dampen relative acceleration between two joints. application this kind civil engineering structures would be practical since works passively. Since angular much more significant than translational mass, does not significantly increase earthquake-induced force. To study effectiveness device in seismically excited structures, applied base-isolated benchmark...

Summary In this study, a constitutive model of high damping rubber bearings (HDRBs) is developed that allows the accurate representation force–displacement relationship including rate‐dependence for shear deformation. The proposed consists two hyperelastic springs and nonlinear dashpot element expresses finite deformation viscoelasticity laws based on classical Zener model. Fletcher–Gent effect, manifested as horizontal stiffness at small strains caused by carbon fillers in HDRBs, accurately...

In this paper, we propose a simple control approach to produce negative stiffness hysteretic loops for the response of base-isolated bridges. The combination controller with those bearing results in virtually rigid perfectly plastic force–deformation characteristics possessing large damping ratio without transmitting excessive force other structural members. proposed has potential be implemented as passive approach. application benchmark problem seismically excited highway bridge been...

SUMMARY A new isolation interface is proposed in this study to retrofit existing buildings with inadequate soft stories as well structures be constructed first story intended for architectural or functional purposes. The seismic an assembly of bearings set parallel on the top columns: multiple‐slider and rubber bearings. bearing a simple sliding device consisting one horizontal two inclined plane surfaces based polytetrafluoroethylene highly polished stainless steel at both ends series....

An integrated algorithm to spectrally match two seed-recorded horizontal bi-directional ground motion components a maximum-direction response spectrum (RotD100) while maintaining the radial spectral acceleration pattern (RadSAP) at target natural periods is presented. The based on complex-discrete-Fourier-transform (CDFT) and iterative manipulation of motions. Initially, population candidate pairs generated, resulting in minimum error RadSAP picked. Subsequently, CDFT coefficients picked...

In this study, the multiple-spring (MS) model with curve-approximated hysteresis rule is proposed for nonlinear seismic response simulation of bidirectionally loaded hollow square-section steel columns such as cantilever type piers. To represent behavior column, an effective and simple optimization procedure introduced to identify free parameters model. A parameter determination approach approximate modeling in preliminary design calculations also introduced. The results quasi-static...

Dynamic components of the control systems involving actuator time delay can strongly influence dynamics controlled floor system. In this paper, an independent modal space design process for active vibration caused by human-induced impact excitation is developed based on direct velocity feedback with a phase-lead compensator using root locus method to enhance stability margins and increase damping each filtered mode. Spillover effects under residual modes are considered through placement...

We numerically investigate quantum dynamics in a one-dimensional double-well system emphasizing influence of parametrically polychromatic perturbation on the dynamics. It is found that time dependence transition probability for an initially localized wave packet between wells shows two types motion, coherent and incoherent depending parameters. As strength and/or number frequency components increase, motion changes into one. The former related to tunneling due coherence; latter delocalized...

We describe highly sensitive photopolymers consisting of a photobase generator (PBG), base-sensitive polymer, and base amplifier that decomposed autocatalytically to release an amine molecule which resulted in the enhancement base-catalyzed reactions polymer. Low molecular weight molecules produced from amplifiers were widely diffused polymer film, resulting reduction resolution power manner "air infection" low basic species, although photosensitivity was enhanced. To improve performance, we...