Dual earthquake resistant frames (original) (raw)
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Bracing configuration in earthquake resistant structure
2011
Technological advances in the seismic design of energy dissipation systems raise the issue of the codes dominated capacity design of structures. Building code requirements that describe the dynamic behavior, modeling and analysis of structures with different types of energy dissipation systems are currently under review. A new seismic design approach, described in the current paper, adds to the current research activities of the authors on passively controlled systems with integrated hysteretic damper and cable bracings. The control system considers at first place the effect of added stiffness when conventional bracings are added to structural frames that are necessary for the integration of the damping devices. An increase in the systems stiffness may result to a reduction of the peak displacement, i.e. peak pseudo-acceleration, and thus to an increase of the shear forces. In addition, an increase in damping can significantly influence the response of elastic and inelastic systems....
Adaptable dual control systems for earthquake resistance
WIT Transactions on the Built Environment, 2011
The use of passive energy dissipation systems for seismic control has been proven internationally over the past years as most promising. The proposed concept of Adaptable Dual Control Systems (ADCS), presented in the present paper, relies on the seismic performance of braced frames with cables or tension only rods, following a closed circuit, and hysteretic dampers. ADCS are based on a dual function of the component members, resulting in two practically uncoupled systems: a primary and a secondary system. The primary frame is responsible for the normal vertical and horizontal forces, while the closed damper-bracing mechanism, for the earthquake forces and the necessary energy dissipation. The bracing members are fixed at the bottom of the columns and are free to move horizontally at the primary frame's joints. Relative displacements are induced between the energy dissipation system's component members and the main frame's members. The potentials for maximum energy dissipation of the proposed systems are investigated in three configurations of the control system. In all cases the damper utilizes the relative displacement between its end joints to yield in the inelastic region, enabling the primary frame to resist elastically. ADCS may result to significant energy dissipation, when all design parameters involved are accordingly predefined. The predominant parameters that characterize ADCS seismic behavior are verified in respect to the mechanical properties of the control elements under the action of ten selected earthquake records of the Greek-Mediterranean region. A comparative parametric analysis of the three systems' seismic behavior leads to significant recommendations for their application as alternative energy dissipation systems.
Earthquake Engineering & Structural Dynamics, 2007
The paper deals with the proposal and the experimental validation of a novel dissipative bracing system for the seismic protection of structures; compared with other similar systems, it is characterized by smaller size and weight, which makes it easier to move and to install, as well as particularly suitable to be inserted in light-framed structures (e.g. steel structures of industrial plants).The proposed system consists of an articulated quadrilateral with steel dissipaters inserted, to be connected by tendons to frame joints; the prototypes have been designed and realized for the seismic protection of a two-storey, large-scale, steel frame, specially designed for shaking-table tests.The paper, after an illustration of the system, and of its design and behaviour, presents the shaking-table tests carried out. The experimental results have fully validated the proposed system, showing its good performance in controlling the seismic response of framed structures.A numerical non-linear model, set up and validated on the basis of the physical tests, has been used to help interpreting the experimental results, but also to perform parametrical studies for investigating the influence of the design parameters on the performance of the control system. Copyright © 2006 John Wiley & Sons, Ltd.
Seismic behaviour of hybrid systems made of PR composite frames coupled with dissipative bracings
Earthquake Engineering & Structural Dynamics, 2008
The paper investigates the dynamic behaviour of hybrid systems made of partially restrained (PR) steelconcrete composite frames coupled with viscoelastic dissipative bracings. A numerical model that accounts for both the resisting mechanisms of the joint and the viscoelastic contribution of the dissipative bracing is introduced and briefly discussed. The model is first validated against experimental outcomes obtained on a one-storey two-bay composite frame with partial strength semi-rigid joints subjected to free vibrations. A number of time-history analyses under different earthquake ground motions and peak ground accelerations are then carried out on the same type of frame. The purpose is to investigate the influence of the type of beam-to-column connection and property of the viscoelastic bracing on the performance of the hybrid system. The inherent stiffness of the bare PR frame and the plastic hysteresis of the beam-to-column joints, which always lead to only limited damage in the joint, are found to provide a significant contribution to the overall structural performance even under destructive earthquakes. This remark leads to the conclusion that the viscoelastic bracing can be effectively used within the hybrid system. 862 C. AMADIO ET AL.
International Journal of Engineering Research and Technology (IJERT), 2016
https://www.ijert.org/seismic-performances-and-evaluation-of-structures-equipped-with-supplemental-brace-damper-system https://www.ijert.org/research/seismic-performances-and-evaluation-of-structures-equipped-with-supplemental-brace-damper-system-IJERTV5IS010633.pdf The usefulness of supplementary energy dissipation devices is now quite well-known in the earthquake structural engineering community for reducing the earthquake-induced response of structural systems. The main objective of this study is, therefore, to formulate a general framework of comparing passive energy dissipation systems for seismic structural applications. The following four types of passive energy dissipation systems have been examined in the study: (1) viscous fluid dampers, (2) viscoelastic dampers, (3) yielding metallic dampers and, (4) friction dampers. For each type of energy dissipation system, effectiveness of each damper is calculated in modifying response of a structure like acceleration, displacement and drift of a structure.
Seismic Performances and Evaluation of Structures Equipped with Supplemental Brace Damper System
International Journal of Engineering Research and, 2016
The usefulness of supplementary energy dissipation devices is now quite well-known in the earthquake structural engineering community for reducing the earthquake-induced response of structural systems. The main objective of this study is, therefore, to formulate a general framework of comparing passive energy dissipation systems for seismic structural applications. The following four types of passive energy dissipation systems have been examined in the study: (1) viscous fluid dampers, (2) viscoelastic dampers, (3) yielding metallic dampers and, (4) friction dampers. For each type of energy dissipation system, effectiveness of each damper is calculated in modifying response of a structure like acceleration, displacement and drift of a structure.
Dual control connections in frames for earthquake resistance
Earthquake Resistant Engineering Structures X, 2015
The behaviour optimization of structures under severe dynamic actions, such as earthquakes, is being increasingly aimed at the control of the stiffness and damping properties of structures. The present paper examines an alternative control mechanism for achieving dynamic structural adaptability. To achieve a larger degree of freedom in the members' control design, a novel dual connection of the primary members of the frame is proposed, which can initially "filtrate" the moment transmission at the joints. The connection consists of elastomeric material fixed at the primary joint areas and the lower column areas of three frames. The elastomeric shear connections are activated from the beginning of the horizontal excitations of the frame. Consequently, the stiffness of the primary system is no longer restricted to the geometric relations of the connected members. The elastic connection enables, primarily, a displacement increase of the structures and a slight increase of their energy dissipation performance. Based on three representative international strong earthquake motions of differing frequency contents, respective numerical nonlinear analyses of a SDOF system exemplify the earthquake performance of the controlled frames with elastic connections. In perspective, the stiffness control concept may enable further objectives in the design to be achieved for a stepwise adaptation by the primary system to the external acting forces through an increase of its damping properties.
Dynamic Tests of a Dissipative Bracing System for Seismic Control of Framed Structures
1970
The paper illustrates the results of an experimental program which deals with dynamic tests on a shaking table of a two-storey, one-bay frame, equipped with dissipative bracing systems. After a description of the general criteria used for the design of the test structure and the definition of the characteristics of the special bracing system, the results of the tests are presented and compared with results obtained by a numerical model of the structure.
Assessment of the performance of hysteretic energy dissipation bracing systems
Bulletin of Earthquake Engineering, 2014
ABSTRACT The advantages of passive supplemental dampers for performance enhancement of new and existing structures have been demonstrated extensively in the past. The big amount of experimental tests carried out all over the world on framed structures upgraded by energy dissipating bracing (EDB) systems based on hysteretic dampers (HDs), have shown their effectiveness in reducing seismic effects on buildings. The mechanical characteristics of the HDs in some cases may be different from those arising by the design procedure due to industrial tolerance or because of some damage suffered during previous earthquakes. In order to assess the robustness of this technique, in terms of capacity of seismic vibrations control even for significant changes in the mechanical characteristics of the EDB system respect to the design ones, in this paper experimental tests and parametric nonlinear time history analysis have been carried out changing the characteristics of the HD stiffness and strength. The experimental results refer to the shaking table tests performed at the Structural Laboratory of the University of Basilicata within a wide research program, named Joint Experimental Testing on Passive and semiActive Control Systems. The program has been completely funded by the Italian Department of Civil Protection within the activity of the Research Line 7 of the ReLUIS (Italian Network of University Laboratories of Earthquake Engineering) 2005-2008 project. A displacement-focused design procedure has been considered to evaluate the mechanical characteristics of the dissipating system, with the aim of limiting inter-storey drifts after frame yielding. From the experimental point of view, two design solutions have been tested for chevron braces equipped with HD, assuming the same stiffness but different values of both ductility demand and yield strength of the HDs. Moreover, parametric studies have been performed through numerical simulations. This paper provides an overview of the experimental set up and briefly summarizes the experimental outcomes and the comparison with the results of numerical nonlinear time history analysis. Moreover, the results of the parametric analysis for the assessment of the performances of the dissipating system in controlling structural response are presented.
IRJET, 2022
Seismic energy dissipation consists of many methods like dampers, viscous dampers etc... But no costeffective method is available for seismic energy dissipation. When seismic energy transfers to the building, the joints like beam and column joint, brace-beam joint etc. tends to fail due to shear. To minimize this shear failures, we can provide shear fuses as energy dissipating system. The beams in which these fuses are installed is referred as "Shear Energy Dissipation Beams" (SEDB). This fuse is placed on the beam where deformations are likely to happen. When seismic energy transfers through this fuse, the fuse fails and protects the primary structure. Then, failed fuse can be replaced with another one. This shear fuses are very cost effective and cheapest method. The modelling and analysis are done using ETABs software.