摘要:

AbstractThe paper presents predictive relations for peak horizontal and vertical ground accelerations generated by earthquakes in the European area.

ISSN:0098-8847    

DOI:10.1002/eqe.4290240402

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA vast amount of earthquake response records of an observation tower are used together with microtremor data to investigate various aspects of the dynamic behaviour of the soil‐structure system. It is found that separation of the soil from the structure occurs under large dynamic loads, leading to changes in the predominant frequency of the system. As a result of the decreasing of the soil support at the side walls of the foundation, the stress caused by the structural weight on the bottom soil increases during earthquakes. With regard to its practical applicability, a linear sway‐rocking model is applied for numerical modelling of the soil‐structure system. Alterations in the soil support as a result of soil non‐linearity and separation of the structure from the soil are investigated by comparing recorded and simulated structural response. The influence of each of these factors on the softening of the soil support is distinctly assessed. An empirical relationship between the peak ground velocity and the soil constants for earthquake excitations of different magnitude is pr

ISSN:0098-8847    

DOI:10.1002/eqe.4290240403

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper proposes the use of neural networks to predict damage due to earthquakes from the indices of recorded ground motion. Since the relationship between ground motion indices and resulting damage is difficult to express in mathematical form, neural networks are conveniently applied for this problem. Simulated earthquake ground motions are used to have a well‐distributed data set and the ductility factor from non‐linear analysis of two single‐degree‐of‐freedom structural models is used to represent the damage. A sensitivity analysis procedure is described to identify qualitatively the input parameters that have a greater influence on the damage. The result of the trained neural network is then verified by using several recorded earthquake ground motions. It is found that some instability in the prediction can occur. Instability occurs when input values exceed the range of the training data. The neural network model using PGA and SI as input give the best performance in the recall tests using actual earthquake ground motion, demonstrating the usefulness of neural network models for the quick estimation of damage through earthquake intensity m

ISSN:0098-8847    

DOI:10.1002/eqe.4290240404

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA simple analytical solution is presented to calculate the pile‐soil‐pile interaction and eventually the dynamic response of pile groups when excited by the passage of Rayleigh waves and obliquely incident SH‐waves. A dynamic Winkler model, with realistic frequency‐dependent ‘springs’ and ‘dashpots’ in conjunction with physically motivated approximations is utilized to compute the wave field radiating from an oscillating pile and the effect of this field on an adjacent pile. The coupled rocking motion of the pile group resulting from Rayleigh waves and the torsional motion of the pile group resulting from SH‐waves is accurately predicted by a simple mathematical expression. The results of the presented method can be obtained with ‘hand calculations’ and are in excellent agreement with results from ‘rigorous’ solutions based on integral equation formulations. It is found that the group response is primarily affected from the phase difference of the input seismic motion at the location of each pile (wave‐passage effect). Pile‐soil‐pile interaction has insignific

ISSN:0098-8847    

DOI:10.1002/eqe.4290240405

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper presents a comparative test of models of self‐controlled and ordinary frames on the shaking table. Two tested 1/8‐scale models of 4‐storey and single‐bay RC frames made of cement mortar and reinforced with wires were poured on the same base beam. The dynamic characteristics and earthquake responses in the elastic, cracked and failed stages and the failure modes of these two kinds of frame are studied. It is proved that the seismic behaviour of the self‐controlled frame is better than that of the ordin

ISSN:0098-8847    

DOI:10.1002/eqe.4290240406

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractStudied in this paper is the inelastic seismic behaviour of asymmetric‐plan buildings using the histories of base shear and torque. The first step in understanding this behaviour is to construct the base shear and torque surface (BST) for the building, which represents all combinations of shear and torque that applied statically lead to collapse of the structure. Several factors controlling the shape of this surface, such as strength eccentricity and bidirectional ground motion, are identified. Also, their effects on the building responses are studied considering several structural configurations. The results obtained show that the BST surface, in conjunction with the base‐shear and torque histories, provides a useful conceptual framework for understanding the behaviour of asymmetric systems. Furthermore, using these surfaces, relevant aspects of the behaviour and design of such buildings become apparent even before dynamic analysis of the struct

ISSN:0098-8847    

DOI:10.1002/eqe.4290240407

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA new simplified model for analysis and design of multistorey buildings is developed. The model is based on a single super‐element per building storey capable of representing the elastic and inelastic properties of the storey. This is done by matching the stiffness matrices and ultimate yield surface of the storey with that of the element; this surface relates storey shear and storey torque. For practical convenience, these surfaces are parametrized in terms of seven important physical parameters controlling the seismic response of asymmetric structures. Several numerical studies showed that the accuracy of the super‐element model is satisfactory for most design purposes; the errors in peak responses are expected to be less than 20 per cent for most practical structures. Among the important advantages of this simplified model is that the time required in formulating, analysing and interpreting the structural model and its response is at least an order of magnitude smaller than for any conventional 3‐D inelastic model. This enables the engineer to try different structural configurations and, thus, produce designs that have the desired seismic behaviour and are cost‐effective. Furthermore, it has been shown through a multistorey building example that the super‐element model is a powerful tool for conceptual design of a building. In spite of its simplicity, the model uses an accurate representation of the storey‐shear and torque surfaces, which enables it to capture the fundamental features controlling the inelastic behaviour of t

ISSN:0098-8847    

DOI:10.1002/eqe.4290240408

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractMicrotremor measurements were conducted in Kushiro City, Hokkaido Island of Japan. The thickness of alluvial deposits in the central area of Kushiro City abruptly changes from 0 to 80 m. Predominant ground motion at a microtremor measuring site is represented by the spectral ratio, the ratio of Fourier amplitude spectrum of microtremor in the horizontal direction to that in the vertical direction. The peak frequency of the spectral ratio corresponds well to the predominant frequency estimated from the thickness of alluvial layer at each site. Based on a hypothesis that the spectral ratio can be regarded identical with a half of the amplification factor from diluvial bed rock to the ground surface, the strong ground motion due to the Kushiro‐oki earthquake at each site is estimated. The method of estimation is verified by the comparison of the synthesized accelerogram with the recorded one at West Port of Kushiro. The results satisfactorily explain major damages and vibrations felt in Kushiro City during the earthquak

ISSN:0098-8847    

DOI:10.1002/eqe.4290240409

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo mode combination methods are presented for structures with non‐classical (non‐proportional) damping. They are of the same level of complexity as the well‐known SRSS and CQC methods. They require only a single, real‐valued participation factor for each mode, a single correlation coefficient, and standard relative displacement response spectra. A base‐isolation study shows that the standard SRSS and CQC methods for classically damped structures give under‐conservative response predictions, and that the proposed methods give accurate

ISSN:0098-8847    

DOI:10.1002/eqe.4290240410

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290240411

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY