摘要:

AbstractModal properties of tuned mass damper (TMD)‐structure two‐degree‐of‐freedom (2DOF) linear systems are studied employing a perturbation technique. Using the perturbation solutions, formulas relevant to designing the TMD for various types of loading are obtained; they are expressed as a function of mass ratio, tuning ratio, damping ratio of the TMD and damping ratio of the structure. Equivalent additional dampings of the structure due to the TMD are derived for random and harmonic forces. Matched expressions of equivalent damping, which are valid for detuned, i.e. non‐optimal, conditions are also presented. The stability boundary of TMD‐structure systems subject to linear self‐excited forces is derived in a closed form. Using the perturbation solutions, procedures for optimizing the TMD parameters for various types of loading are explained and the optimal values are derived. The formulas obtained in this study can be used with good accuracy for mass ratios l

ISSN:0098-8847    

DOI:10.1002/eqe.4290221002

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe behaviour of the EPP‐SDOF model under seismic actions is analysed herein by different ‘damage functionals’ to define collapse under cyclic loading. In particular, the damage functionals based on the concept of maximum ductility and dissipated plastic energy are first compared. Afterwards the methods of Banon and Veneziano, Park and Ang and the linear cumulative law of plastic fatigue are reviewed and extensively analysed. Comparisons in the case of simple cyclic histories and in terms of acceleration collapse spectra are carried out with reference to significant earthquake records. In particular, it is shown in which cases the damage functionals of Banon and Veneziano, Park and Ang and the linear cumulative law of plastic fatigue, completely defined by the value of a single parameter, degenerate in the limit methods of ductility or dissipated energy and in which cases they provide similar re

ISSN:0098-8847    

DOI:10.1002/eqe.4290221003

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper describes an analysis of damage costs to commercial and industrial property, including buildings (all low‐rise), their contents, equipment and stock, in the Ms= 6.6 Edgecumbe New Zealand earthquake of 2 March 1987. The damage costs were converted to damage ratios by dividing by the value of the relevant property item. For the MM7 and MM9 intensity zones, the mean values and statistical distributions of these damage ratios were then found, the lognormal distribution fitting well.For all commercial and industrial buildings in the MM intensity IX zone (centroid MM9‐4) the mean damage ratio was 0.076. The mean damage ratios were generally much smaller than estimated in previous studies. The buildings were all low‐rise. There was no correlation between building and equipment damage ratios on a building by building basis. Considering dates of construction, it appears that mean damage levels at MM9 have not changed significantly for postcode buildings through changes in design standards up to the

ISSN:0098-8847    

DOI:10.1002/eqe.4290221004

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractDiscrete elastic–plastic systems subjected to dynamic load conditions are considered and properties related to an implicit time‐integration scheme are discussed on the basis of an internal variable formulation. The material models accounted for are quite general: elastic–perfectly plastic and elastic–plastic (subjected to linear or non‐linear, kinematic or isotropic hardening). The internal variable approach adopted in the paper leads easily to extremum theorems from which convergence properties of convenient time‐integration schemes immediately follow. Next, taking account of the stabilising effect due to inertial and damping forces, it is shown how the above results can be extended to the case of softening (again linear or non‐linear, kinematic or isotropic). Finally, some numerical examples are given and an extension to damage models

ISSN:0098-8847    

DOI:10.1002/eqe.4290221005

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents the results of a unique field test on a curved highway overpass. In the test, large horizontal loads were applied to the superstructure of the bridge and quickly released, causing the bridge to vibrate. The resulting large‐amplitude vibrations were intended to be similar to the vibrations caused by earthquakes (horizontal accelerations of up to 25 per cent of gravity were measured on the bridge deck). Well‐defined lateral, longitudinal, vertical and torsional vibration modes were identified from the test data.The vibration modes were used to verify an analytical model of the bridge's dynamic response. For this paper, the model was verified using only the fundamental vibration mode, which was primarily a horizontal vibration mode. Using a system identification procedure, the dynamic response model was adjusted until its frequency and mode shape matched the measured frequency and mode shape. Parameters in the verified model were compared with the same parameters calculated from information in the structural drawings. Because the fundamental mode represents a horizontal mode, the bridge parameters identified in this paper were those parameters which strongly influence the horizontal response of the bri

ISSN:0098-8847    

DOI:10.1002/eqe.4290221006

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290221007

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290221001

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY