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The effect of tuned-mass dampers on the seismic response of base-isolated structures
240A
SURFACE STRUCfURES:DYNAMIC
LOADS
955384 Story-drift, shear, and OTM estimation from building seismic records S. T. Mau & V. Aruna, Journal of Structural Engineering ASCE, 120(11), 1994, pp 3366-3385.
955308 Seismic hazard analysis of nonlinear structures. II: applications P. Bazzurro & C. A. Cornell, Journal of Structural Engineering - ASCE, 120(11), 1994, pp 3345-3365.
A method of determining story drift, shear, and overturning moment (OTM) from building seismic records is presented. It is found that story shear and overturning moment may be estimated accurately while certain error is associated with story-drift estimates. Results of the error assessment may be used as guidelines for the selection of floor locations for the deployment of accelerometers. The method is also demonstrated over the actual seismic record of two buildings. (Authors)
The present paper provides the detailed procedure for the empirical estimation of the (mean) nonlinear response factor ~FDM] for real, complex structures. The application is made practical by the relatively few nonlinear dynamic analyses necessary. Improved software and computational efficiency has brought such analyses within the same general accessibility and cost range as linear dynamic analyses. (from Authors)
955305 Non&rear seismic analysis of space structures with partially restrained connections L. Gao & A. Haldar, Microcomputers in Civil Engineering, 10(l), 1995, pp 27-37. An ’efficient and robust method is developed using the assumed stress-based finite-element method in which the tangent stiffness can be expressed in explicit form and fewer elements are needed to model a structure. For the dynamic and seismic analyses, three major sources of damping are considered. They are viscous damping, hysteretic damping in the PR connections, and the hysteretic damping at the plastic hinges, if plastic hinges are developed in the structure. Proper consideration of PR connections is essential in modeling the realistic dynamic and seismic behavior of structures. Numerical results show that the presence of partially restrained connections may not cause failure of a structure due to insufficient strength but may make serviceability constraints, e.g., the lateral deformation, more critical. (from Authors) 955306 The effect of tuned-mass dampers on the seismic response of base-isolated structures Hsiang-Chuan Tsai, International Journal of Solids & Structures, 32(8-g), 1995, pp 1195-1210. The effect of applying tuned-mass dampers towards reducing the lateral deformation of isolators was studied in this paper. The choice of the proper parameters of the tuned-mass damper and the influence of excitation frequency on the response were investigated. Through the numerical simulation of a five-stomy base-isolated building subjected to different earthquake records, it was found that although the tunedmass damper had little effect on structural response during the first few seconds of earthquake exicitation, the damper may add damping to the structure to reduce the subsequent response. The idea of the accelerated tuned-mass damper is proposed. (from Author) 955307 Seismic hazard analysis of nonlinear structures. I: methodology P. Bazzurro & C. A. Cornell, Journal of Structural Engineering - ASCE, 120(1 l), 1994, pp 3320-3344. Conventional seismic hazard analysis methodology is generalized to estimate directly the annual seismic risk of exceeding a specified level of postelastic damage in real structures. Using a two-dimensional model of a jacket-type offshore platform and a large sample of observed time histories, it is confirmed that: 1) There is no significant dependence of the average of FDM (response factor) magnitude and distance; and 2) its coefficient of variation is relatively small. These are confirmed for both local (member-level) damage measures and global collapse, for variations in structure and foundation modeling, and for various durations. (Authors)
955309 Methodology for forensic investigations of seismic damage D. Castaneda & C. Brown, Journal of Structural Engineering - ASCE, 120(12), 1994, pp 3506-3524. A methodology is presented ‘for conducting forensic investigations of earthquake-damaged structures. Methods for conducting probabilistic and fuzzy-set damage-assessments are discussed. Methods for identifying, studying, and ranking causes of unexpected damage are presented. A fundamental desideratum is proposed to maintain uniform levels of precision in the required analyses. Results are presented in layers to determine the professional significance of the unexpected damage. This methodology is applied to the forensic investigation of a three-story reinforced-concrete office building damaged in the 1987 Whittier Narrows earthquake. (Authors) 955310 Eartbquake response estimation and control of equipment supported by frames K. Tagawa & N. Shirasaki, JSME International Journal, Series C, 37(4), 1994, pp 719-727. This paper aims to examine the effects of dynamic interaction on the maximum base shear distribution between two kinds of structural components, that is, the equipment and its supporting frames, and on the vibratory energy consumption of the damping devices placed between these two structural components. The random vibration theory is applied to obtain the average peak responses of simplified interaction models placed on a base which is stimulated by ground acceleration having the standard power spectrum. The expected ratio of the maximum rocking moment shared between the two structural components of the dynamic model is obtained as a function of the dynamic characteristics of each constituent component and the interaction spring, and the maximum response is reduced by the intermediate damping devices. (Authors) 955311 Dynamic response of single piles embedded in transversely isotropic layered media Weiming Liu & M. Novak, Earthquake Engineering & Structural Dynamics, 23(11), 1994, pp 1239-1257. Dynamic response of single piles embedded in transversely isotropic layered media is investigated using the finite element method combined with dynamic stiffness matrices of the soil derived from Green’s functions for ring loads. The influence of soil anisotropy on the dynamic behaviour of piles is examined through a series of parametric studies. (Authors) 955312 Inverse analysis of the magnitude and direction of impact force H. Inoue, N. Ikeda, K. Kishimoto, T. Shibuya 8c T. Koizumi, JSME International Journal, Series A: Mechanics & Material Engineering, 38(l), 1995, pp 84-91.
SURFACE STRUCfURES:DYNAMIC
LOADS
955384 Story-drift, shear, and OTM estimation from building seismic records S. T. Mau & V. Aruna, Journal of Structural Engineering ASCE, 120(11), 1994, pp 3366-3385.
955308 Seismic hazard analysis of nonlinear structures. II: applications P. Bazzurro & C. A. Cornell, Journal of Structural Engineering - ASCE, 120(11), 1994, pp 3345-3365.
A method of determining story drift, shear, and overturning moment (OTM) from building seismic records is presented. It is found that story shear and overturning moment may be estimated accurately while certain error is associated with story-drift estimates. Results of the error assessment may be used as guidelines for the selection of floor locations for the deployment of accelerometers. The method is also demonstrated over the actual seismic record of two buildings. (Authors)
The present paper provides the detailed procedure for the empirical estimation of the (mean) nonlinear response factor ~FDM] for real, complex structures. The application is made practical by the relatively few nonlinear dynamic analyses necessary. Improved software and computational efficiency has brought such analyses within the same general accessibility and cost range as linear dynamic analyses. (from Authors)
955305 Non&rear seismic analysis of space structures with partially restrained connections L. Gao & A. Haldar, Microcomputers in Civil Engineering, 10(l), 1995, pp 27-37. An ’efficient and robust method is developed using the assumed stress-based finite-element method in which the tangent stiffness can be expressed in explicit form and fewer elements are needed to model a structure. For the dynamic and seismic analyses, three major sources of damping are considered. They are viscous damping, hysteretic damping in the PR connections, and the hysteretic damping at the plastic hinges, if plastic hinges are developed in the structure. Proper consideration of PR connections is essential in modeling the realistic dynamic and seismic behavior of structures. Numerical results show that the presence of partially restrained connections may not cause failure of a structure due to insufficient strength but may make serviceability constraints, e.g., the lateral deformation, more critical. (from Authors) 955306 The effect of tuned-mass dampers on the seismic response of base-isolated structures Hsiang-Chuan Tsai, International Journal of Solids & Structures, 32(8-g), 1995, pp 1195-1210. The effect of applying tuned-mass dampers towards reducing the lateral deformation of isolators was studied in this paper. The choice of the proper parameters of the tuned-mass damper and the influence of excitation frequency on the response were investigated. Through the numerical simulation of a five-stomy base-isolated building subjected to different earthquake records, it was found that although the tunedmass damper had little effect on structural response during the first few seconds of earthquake exicitation, the damper may add damping to the structure to reduce the subsequent response. The idea of the accelerated tuned-mass damper is proposed. (from Author) 955307 Seismic hazard analysis of nonlinear structures. I: methodology P. Bazzurro & C. A. Cornell, Journal of Structural Engineering - ASCE, 120(1 l), 1994, pp 3320-3344. Conventional seismic hazard analysis methodology is generalized to estimate directly the annual seismic risk of exceeding a specified level of postelastic damage in real structures. Using a two-dimensional model of a jacket-type offshore platform and a large sample of observed time histories, it is confirmed that: 1) There is no significant dependence of the average of FDM (response factor) magnitude and distance; and 2) its coefficient of variation is relatively small. These are confirmed for both local (member-level) damage measures and global collapse, for variations in structure and foundation modeling, and for various durations. (Authors)
955309 Methodology for forensic investigations of seismic damage D. Castaneda & C. Brown, Journal of Structural Engineering - ASCE, 120(12), 1994, pp 3506-3524. A methodology is presented ‘for conducting forensic investigations of earthquake-damaged structures. Methods for conducting probabilistic and fuzzy-set damage-assessments are discussed. Methods for identifying, studying, and ranking causes of unexpected damage are presented. A fundamental desideratum is proposed to maintain uniform levels of precision in the required analyses. Results are presented in layers to determine the professional significance of the unexpected damage. This methodology is applied to the forensic investigation of a three-story reinforced-concrete office building damaged in the 1987 Whittier Narrows earthquake. (Authors) 955310 Eartbquake response estimation and control of equipment supported by frames K. Tagawa & N. Shirasaki, JSME International Journal, Series C, 37(4), 1994, pp 719-727. This paper aims to examine the effects of dynamic interaction on the maximum base shear distribution between two kinds of structural components, that is, the equipment and its supporting frames, and on the vibratory energy consumption of the damping devices placed between these two structural components. The random vibration theory is applied to obtain the average peak responses of simplified interaction models placed on a base which is stimulated by ground acceleration having the standard power spectrum. The expected ratio of the maximum rocking moment shared between the two structural components of the dynamic model is obtained as a function of the dynamic characteristics of each constituent component and the interaction spring, and the maximum response is reduced by the intermediate damping devices. (Authors) 955311 Dynamic response of single piles embedded in transversely isotropic layered media Weiming Liu & M. Novak, Earthquake Engineering & Structural Dynamics, 23(11), 1994, pp 1239-1257. Dynamic response of single piles embedded in transversely isotropic layered media is investigated using the finite element method combined with dynamic stiffness matrices of the soil derived from Green’s functions for ring loads. The influence of soil anisotropy on the dynamic behaviour of piles is examined through a series of parametric studies. (Authors) 955312 Inverse analysis of the magnitude and direction of impact force H. Inoue, N. Ikeda, K. Kishimoto, T. Shibuya 8c T. Koizumi, JSME International Journal, Series A: Mechanics & Material Engineering, 38(l), 1995, pp 84-91.