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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Earthquakes and Structures
Journal Basic Information
Journal DOI :
Editor in Chief :
Izuru Takewaki / Stavros A. / Anagnostopoulos / Jerome P. Lynch
Volume & Issues
Volume 3, Issue 6 - Dec 2012
Volume 3, Issue 5 - Sep 2012
Volume 3, Issue 3_4 - Jun 2012
Volume 3, Issue 2 - Apr 2012
Volume 3, Issue 1 - Jan 2012
Selecting the target year
Options for sustainable earthquake-resistant design of concrete and steel buildings
Gilmore, Amador Teran ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 783~804
DOI : 10.12989/eas.2012.3.6.783
Because of its large contribution to the environmental instability of the planet, the building industry will soon be subjected to a worldwide scrutiny. As a consequence, all professionals involved in the building industry will need to create a professional media in which their daily work adequately solves the technical issues involved in the conception, design and construction of concrete and steel buildings, and simultaneously convey care for the environment. This paper discusses, from the point of view of a structural engineer involved in earthquake-resistant design, some of the measures that can be taken to promote the consolidation of a building industry that is capable of actively contributing to the sustainable development of the world.
Robust passive damper design for building structures under uncertain structural parameter environments
Fujita, Kohei ; Takewaki, Izuru ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 805~820
DOI : 10.12989/eas.2012.3.6.805
An enhanced and efficient methodology is proposed for evaluating the robustness of an uncertain structure with passive dampers. Although the structural performance for seismic loads is an important design criterion in earthquake-prone countries, the structural parameters such as storey stiffnesses and damping coefficients of passive dampers are uncertain due to various factors or sources, e.g. initial manufacturing errors, material deterioration, temperature dependence. The concept of robust building design under such uncertain structural-parameter environment may be one of the most challenging issues to be tackled recently. By applying the proposed method of interval analysis and robustness evaluation for predicting the response variability accurately, the robustness of a passively controlled structure can be evaluated efficiently in terms of the so-called robustness function. An application is presented of the robustness function to the design and evaluation of passive damper systems.
New three-layer-type hysteretic damper system and its damping capacity
Kim, Hyeong Gook ; Yoshitomi, Shinta ; Tsuji, Masaaki ; Takewaki, Izuru ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 821~838
DOI : 10.12989/eas.2012.3.6.821
This paper proposes a new three-layer pillar-type hysteretic damper system for residential houses. The proposed vibration control system has braces, upper and lower frames and a damper unit including hysteretic dampers. The proposed vibration control system supplements the weaknesses of the previously proposed post-tensioning vibration control system in the damping efficiency and cumbersomeness of introducing a post-tension. The structural variables employed in the damper design are the stiffness ratio
, the ductility ratio
, and the ratio
of the damper's shear force to the maximum resistance. The hysteretic dampers are designed so that they exhibit the targeted damping capacity at a specified response amplitude. Element tests of hysteretic dampers are carried out to examine the mechanical property and to compare its restoring-force characteristic with that of the analytical model. Analytical studies using an equivalent linearization method and time-history response analysis are performed to investigate the damping performance of the proposed vibration control system. Free vibration tests using a full-scale model are conducted in order to verify the damping capacity and reliability of the proposed vibration control system. In this paper, the damping capacity of the proposed system is estimated by the logarithmic decrement method for the response amplitudes. The accuracy of the analytical models is evaluated through the comparison of the test results with those of analytical studies.
Earthquake time-frequency analysis using a new compatible wavelet function family
Moghaddam, Amir Bazrafshan ; Bagheripour, Mohammad H. ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 839~852
DOI : 10.12989/eas.2012.3.6.839
Earthquake records are often analyzed in various earthquake engineering problems, making time-frequency analysis for such records of primary concern. The best tool for such analysis appears to be based on wavelet functions; selection of which is not an easy task and is commonly carried through trial and error process. Furthermore, often a particular wavelet is adopted for analysis of various earthquakes irrespective of record's prime characteristics, e.g. wave's magnitude. A wavelet constructed based on records' characteristics may yield a more accurate solution and more efficient solution procedure in time-frequency analysis. In this study, a low-pass reconstruction filter is obtained for each earthquake record based on multi-resolution decomposition technique; the filter is then assigned to be the normalized version of the last approximation component with respect to its magnitude. The scaling and wavelet functions are computed using two-scale relations. The calculated wavelets are highly efficient in decomposing the original records as compared to other commonly used wavelets such as Daubechies2 wavelet. The method is further advantageous since it enables one to decompose the original record in such a way that a clear time-frequency resolution is obtained.
Telescopic columns as a new base isolation system for vibration control of high-rise buildings
Hosseini, Mahmood ; Farsangi, Ehsan Noroozinejad ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 853~867
DOI : 10.12989/eas.2012.3.6.853
In this paper, a new type of passive energy dissipating system similar to added damping and stiffness (ADAS) and triangular added damping and stiffness (TADAS) is proposed and implemented in the analytical model of a building with hybrid structural system in the structure's base which we call it; Telescopic column. The behavior and performance of a high rise R.C. structure equipped with this system is investigated and compared with conventional base isolation systems such as rubber isolator bearings and friction pendulum bearings. For this purpose a series of ground acceleration records of the San Fernando, Long Beach and Imperial Valley earthquakes are used as the disturbing ground motions in a series of numerical simulations. The nonlinear numerical modeling which includes both material and geometric nonlinearities were carried out by using SAP2000 program. Results show suitable behavior of structures equipped with telescopic columns in controlling the upper stories drifts and accelerations.
Effects of ground motion scaling on nonlinear higher mode building response
Wood, R.L. ; Hutchinson, T.C. ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 869~887
DOI : 10.12989/eas.2012.3.6.869
Ground motion scaling techniques are actively debated in the earthquake engineering community. Considerations such as what amplitude, over what period range and to what target spectrum are amongst the questions of practical importance. In this paper, the effect of various ground motion scaling approaches are explored using three reinforced concrete prototypical building models of 8, 12 and 20 stories designed to respond nonlinearly under a design level earthquake event in the seismically active Southern California region. Twenty-one recorded earthquake motions are selected using a probabilistic seismic hazard analysis and subsequently scaled using four different strategies. These motions are subsequently compared to spectrally compatible motions. The nonlinear response of a planar frameidealized building is evaluated in terms of plasticity distribution, floor level acceleration and uncorrelated acceleration amplification ratio distributions; and interstory drift distributions. The most pronounced response variability observed in association with the scaling method is the extent of higher mode participation in the nonlinear demands.
Uni-axial behaviour of normal-strength concrete-filled-steel-tube columns with external confinement
Ho, J.C.M. ; Luo, L. ;
Earthquakes and Structures, volume 3, issue 6, 2012, Pages 889~910
DOI : 10.12989/eas.2012.3.6.889
Because of the heavy demand of confining steel to restore the column ductility in seismic regions, it is more efficient to confine these columns by hollow steel tube to form concrete-filled-steel-tube (CFST) column. Compared with transverse reinforcing steel, steel tube provides a stronger and more uniform confining pressure to the concrete core, and reduces the steel congestion problem for better concrete placing quality. However, a major shortcoming of CFST columns is the imperfect steel-concrete interface bonding occurred at the elastic stage as steel dilates more than concrete in compression. This adversely affects the confining effect and decrease the elastic modulus. To resolve the problem, it is proposed in this study to use external steel confinement in the forms of rings and ties to restrict the dilation of steel tube. For verification, a series of uni-axial compression test was performed on some CFST columns with external steel rings and ties. From the results, it was found that: (1) Both rings and ties improved the stiffness of the CFST columns and (2) the rings improve significantly the axial strength of the CFST columns while the ties did not improve the axial strength. Lastly, a theoretical model for predicting the axial strength of confined CFST columns will be developed.