Search Issue | RSS Feeds RSS
Previous Issue

November 1993

Volume 9, Issue 4, pp. 643-887


Foreword

James E. Beavers

Earthquake Spectra 9, pp. iii-iii (1993); doi:http://dx.doi.org/10.1193/1.1585746

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Abstract Unavailable

A New Method for the Realistic Estimation of Seismic Ground Motion in Megacities: the Case of Rome

Donat Fäh, Claudio Iodice, Peter Suhadolc, and Guilano F. Panza

Earthquake Spectra 9, pp. 643-668 (1993); doi:http://dx.doi.org/10.1193/1.1585735 | Cited 4 times

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
A hybrid technique, based on mode summation and finite differences, is used to simulate the ground motion induced in the city of Rome by the January 13, 1915, Fucino (Italy) earthquake (ML=6.8). The technique allows us to take into consideration source, path, and local soil effects. The results of the numerical simulations are used for a comparison between the observed distribution of damage in Rome, and the computed peak ground acceleration, the maximum response of simple oscillators, and the so‐called “total energy of ground motion”. The total energy of ground motion is in good agreement with the observed distribution of damage. From the computation of spectral ratios, it has been recognized that the presence of a near‐surface layer of rigid material is not sufficient to classify a location as a “hard‐rock site” when the rigid material has a sedimentary complex below it. This is because the underlying sedimentary complex causes amplifications due to resonances. Within sedimentary basins, incident energy in certain frequency bands can also be shifted from the vertical, into the radial component of motion. This phenomenon is very localized, both in frequency and space, and closely neighboring sites can be characterized by large differences in the seismic response.

Monte‐Carlo Simulation of the Theoretical Site Response Variability at Turkey Flat, California, Given the Uncertainty in the Geotechnically Derived Input Parameters

Edward H. Field, M.EERI and Klaus H. Jacob, M.EERI

Earthquake Spectra 9, pp. 669-701 (1993); doi:http://dx.doi.org/10.1193/1.1585736 | Cited 1 time

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
In the weak‐motion phase of the Turkey Flat blind‐prediction effort, it was found that given a particular physical model of each sediment site, various theoretical techniques give similar estimates of the site response. However, it remained to be determined how uncertainties in the physical model parameters influence the theoretical predictions. We have studied this question by propagating the physical parameter uncertainties into the theoretical site‐response predictions using monte‐carlo simulations. The input‐parameter uncertainties were estimated directly from the results of several independent geotechnical studies performed at Turkey Flat. While the computed results generally agree with empirical site‐response estimates (average spectral ratios of earthquake recordings), we found that the uncertainties lead to a high degree of variability in the theoretical predictions. Most of this variability comes from poor constraints on the shear‐wave velocity and thickness of a thin (~2m) surface layer, and on the attenuation of the sediments. Our results suggest that in site‐response studies which rely exclusively on geotechnically based theoretical predictions, it will be important that the variability resulting from input‐parameter uncertainties is recognized and accounted for.

Seismic Design of Buildings in China

Hu Shiping

Earthquake Spectra 9, pp. 703-737 (1993); doi:http://dx.doi.org/10.1193/1.1585737 | Cited 1 time

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
This paper gives the reader a general perspective on the subject of seismic design of buildings in China and may be of special interest to those who may do building design in that country. In the introduction, the main characteristics of Chinese earthquakes, some major earthquake disasters in the past, and a brief history of seismic design in China are related. The paper goes on to relate some new features of the recently promulgated seismic code which include a new design spectrum, how to identify liquefiable soil, the three levels of seismic protection, and the two‐phase design. The paper also presents the seismic design of multistory brick and reinforced concrete buildings which differs somewhat from that of other countries, and three examples of actual design.

Analysis of Strong Motion Records from Uttarkashi Earthquake for Assessment of Code Provisions for Different Seismic Zones

Sudhir K. Jain, M.EERI and Satrajit Das

Earthquake Spectra 9, pp. 739-754 (1993); doi:http://dx.doi.org/10.1193/1.1585738

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
Strong motion records have been obtained at 13 stations during the Uttarkashi earthquake of October 20, 1991 (magnitude 6.6). A study has been conducted on these time histories to assess the codal provisions in India. Emphasis of the study is on evaluating relative consistency of design provisions for different seismic zones in India. The average response spectra from this earthquake show concentration of significantly more energy in low period range and less energy in high period range. The magnitude of seismic design force for zones I, II, and III is consistent while it is too low for zone IV; no records were obtained in area with shaking intensity corresponding to zone V. It is seen that for buildings in zones I, II, and III, the present design provisions may be lowered either by relaxing the requirement of special ductile detailing, or by reducing the design force. On the other hand, design provisions for zone IV need to be revised upwards.

Tests on Steel and Composite Beam‐to‐Column Connections Strength and Stiffness Aspects

Aristotle K. Kakaliagos, M.EERI and Jack G. Bouwkamp, M.EERI

Earthquake Spectra 9, pp. 755-780 (1993); doi:http://dx.doi.org/10.1193/1.1585739

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
The connection interface of seven welded and bolted beam‐to column connections under cyclic alternating loads, has been studied. Three fully welded connections were designed to compare the effect of filled‐in concrete in a typical steel column section (a composite section) with the response of typical welded connections with and without column‐web stiffeners. A similar set of three specimens were tested to assess the composite effect for connections with bolted endplates. A final, seventh, bolted beam‐column connection, with composite sections for both the column and the beam, was also tested. The test results have demonstrated the effectiveness of concrete in replacing the stiffeners. Compared to the welded unstiffened connection, the use of bolted endplate connections or of composite column sections can increase the elastic moment‐rotation stiffness of the connection, introducing however cyclic stiffness degrading phenomena when stressed beyond the elastic limit.

Assessment and Retrofit of a Reinforced Concrete Bridge Pier for Seismic Resistance

R. Park, M.EERI, M. E. Rodriguez, M.EERI, and D.R. Dekker

Earthquake Spectra 9, pp. 781-801 (1993); doi:http://dx.doi.org/10.1193/1.1585740 | Cited 4 times

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
Typical structural deficiencies in some reinforced concrete bridges designed for seismic resistance before current seismic codes were introduced are briefly outlined. Results of simulated seismic load tests conducted on the critical region of a reinforced concrete bridge pier designed in New Zealand in 1936 are presented. The tests involved the application of compressive axial loading and quasi‐static cyclic lateral loading to a full‐scale subassemblage representing the column‐cap beam region of the as‐built pier. Subsequent loading tests were conducted on the pier retrofitted mainly by the addition of steel plates welded to the ends of the plain round longitudinal bars to improve anchorage. The improved bar anchorage enabled the pier to develop its full theoretical flexural strength, but the considerable loss of stiffness due to bond degradation which occurred in the initial test on the as‐built pier was not restored.

Seismic Vulnerability Evaluation of Bridges in Memphis and Shelby County, Tennessee

S. Pezeshk, M.EERI, T.S. Chang, M.EERI, K.C. Yiak, M.EERI, and H.T. Kung

Earthquake Spectra 9, pp. 803-816 (1993); doi:http://dx.doi.org/10.1193/1.1585741 | Cited 1 time

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
The focus of this paper is to develop a screening procedure to obtain information and assess vulnerability of bridges located in the New Madrid seismic zone (NMSZ). This screening methodology includes structural elements, site, foundation, and importance of the bridge. An inventory of the river‐crossing bridges in Memphis and Shelby County is made using the developed screening procedure; potentially hazardous bridges that require further detailed seismic evaluation and/or immediate seismic retrofitting are identified. The results of this study are important for future maintenance and improvement, earthquake loss estimates, seismic hazard/risk reduction, and earthquake preparedness/rescue plans for river‐crossing bridges in the NMSZ.

Design Strategies for the Seismic Retrofit of Reinforced Concrete Frames

José A. Pincheira, M.EERI

Earthquake Spectra 9, pp. 817-842 (1993); doi:http://dx.doi.org/10.1193/1.1585742

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
Due to economical and practical considerations, the seismic rehabilitation of buildings is generally confined to strategic areas of the structure in which only selected elements are modified or new elements are added. While these modified or new elements can be designed to have substantial strength and ductility, studies have shown that unless the retrofit scheme is stiff enough to control lateral drifts, significant damage to existing non‐strengthened elements can be expected. This paper summarizes some of the results of a series of analytical studies conducted on prototype reinforced concrete frames strengthened with some of the most commonly used rehabilitation techniques. Based on the results of these studies, a design strategy that uses lateral drift rather than lateral strength as the main criterion for the design of retrofit schemes is presented.

New Directions in Structural Seismic Designs

Egor P. Popov, M.EERI, Tzong‐Shuoh Yang, and Carl E. Grigorian

Earthquake Spectra 9, pp. 845-875 (1993); doi:http://dx.doi.org/10.1193/1.1585743 | Cited 4 times

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Show Abstract
The code stipulated seismic force requirements for buildings from the historical point of view are described first. This is followed by examples of the emerging criteria of inelastic seismic spectra for displacement ductility, and number of yield reversals as a function of building period and strength. Novel spatial representations of seismic input energy and hysteresis energy, interpreted as damage energy, are given next. The available structural resistance countering the imposed seismic demand is illustrated by the ductile behavior of steel moment resisting frames (MRFs) and eccentrically braced frames (EBFs). A discussion of a practical and versatile frictional energy dissipating connection is given at the end.

Technical Note: When Does Seismic Hazard Jump?

Nitzan Rabinowitz, David M. Steinberg, and Gideon Leonard

Earthquake Spectra 9, pp. 877-883 (1993); doi:http://dx.doi.org/10.1193/1.1585744 | Cited 1 time

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Abstract Unavailable

Technical Note: Bureau of Reclamation Strong Motion Instrumentation Program

Andy Viksne, M.EERI, Chris Wood, and David Copeland

Earthquake Spectra 9, pp. 885-887 (1993); doi:http://dx.doi.org/10.1193/1.1585745

Online Publication Date: 30 April 2003

Full Text: | Download PDF

Abstract Unavailable
Close

Your Recent History Recent History Help

Recently Viewed

  1. A Computationally Efficient Ground-Motion Selection Algorithm for Matching a Target Response Spectrum Mean and Variance
  2. Scenario Simulation Group Reactions to the Aftermath of the Great ShakeOut Magnitude 7.8 Earthquake
  3. Preparing for a “Big One”: The Great Southern California ShakeOut
  4. Economic Resilience Lessons from the ShakeOut Earthquake Scenario
  5. Economic Impacts of the ShakeOut Scenario
Copyright © Earthquake Engineering Research Institute
Help Contact
close