European Seismic Design Practice - Research and Application

Proceedings of the 5th SECED conference, Chester, UK, 26-27 October 1995

A.S. Elnashai

• Publisher: CRC Press
• Year: 2022
• Print ISBN: 9789054105886
• eBook ISBN: 9781351449441
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

It is evident that European earthquake engineering research and design practice is assuming a role of increasing importance on the international scene. This is primarily due to two considerations; firstly the emergence of a core of European earthquake engineers who are co-operating on a long-term basis for the development of seismic design criteria specific to the European environment and secondly the identification of new problems in existing design practice in the USA and in Japan. It is in this context that European earthquake engineering activities and publications are eagerly observed and awaited by the international community. Includes a compact set of papers from leading research institutions, laboratories and companies in Europe, with a healthy number of contributions from elsewhere. It represents the European state-of-the-art and practice in earthquake testing, analysis & design of civil engineering works as well as strong-motion & hazard studies.

1 Seismic hazard and design

DOI: 10.1201/9780203756492-9

Long period earthquake risk in Europe

G. Woo

EQE International, London, UK

DOI: 10.1201/9780203756492-10

ABSTRACT: Exposure to long period earthquake risk is a concern for many existing structures in Europe, and is increasing with the development of major construction projects. The degree of hazard varies from site to site within Europe due not only to seismic source variability, but also spatial and azimuthal variations in attenuation. An assessment of long period risk in Europe is currently being conducted under the auspices of the European Union Environment programme.

1 THE GROWTH OF LONG PERIOD RISK

Throughout Europe, there are large extended structures which are potentially susceptible to long period seismic ground motion. Yet more ambitious projects are planned, including a new bridge across the River Tagus in Lisbon, a bridge across the Messina Straits, and even a bridge across the Gibraltar Straits is contemplated. The crowding of skylines with ever taller towering buildings has become a feature of urban environments across the continent. The drive for industrial efficiency and cheaper unit costs has motivated the construction of ever larger storage silos, tanks and ponds, taller chimneys and longer pipelines. Special tourist sightseeing facilities, such as tall observation towers, are becoming popular in resort areas.

The time span from conception to execution of these major engineering projects is typically shorter than the return period for the occurrence of menacing long period earthquake shaking, which may be much longer than a century. Sustained severe long period vibrations are generated by coherent ruptures generally associated with the larger earthquakes. These are comparatively rare in Europe, but they do occur intermittently. In between such occasional events, engineering awareness of this form of risk may be gradually eroded, and preparedness may be enervated by a misguided sense of complacency in implementing building codes.

Nothing concentrates the mind of the earthquake engineer so much as actual practical experience of a hypothesized loading scenario. In many parts of Europe, even those where there is a general appreciation of local seismic hazard, the long period component of risk may be perceived to be remote if it has not been manifest for several generations. The same holds in many other parts of the world, including Japan, where, at the time of the great 1923 Kanto earthquake, there was a maximum height restriction of 31 metres for buildings. No testing magnitude 8 earthquake has struck Tokyo since the relaxation of this regulation.

Recent examples of poor designs include a set of storage silos lacking sufficient anchoring and separation to withstand long period shaking from a plausible regional earthquake. Going further back to the 1960’s and 1970’s, deficiencies in the state-of-the-art in seismic design, including long period design, have been exposed in a number of damaging earthquakes of the past decade, and structures of this generation should be reviewed for seismic safety. Regrettably, the state of understanding of long period seismic hazard has not reached a level where ground motion specification for building codes can be provided authoritatively and with scientific conviction. Thus even for well-designed modern structures complying with the codes, some residual doubt must remain over the adequacy of provision for long period shaking.

As with any unfamiliar phenomenon, recovery and study of available information on past events are prerequisites for furthering knowledge and understanding. In respect of long period seismic ground motion, relevant information is to be found in historical archive material and long period seismograms recorded from major European earthquakes. These sources of information have been examined as part of a multi-disciplin...

Table of contents

• Cover Page
• Half Title Page
• Title Page
• Copyright Page
• Table of Contents
• Foreword
• Keynote papers
• 1 Seismic hazard and design
• 2 Behaviour of bridges
• 3 Seismic design and analysis
• 4 Site characteristics and geotechnics
• 5 Earthquake testing
• 6 Seismic analysis
• 7 Steel structures
• 8 Reinforced concrete testing
• 9 Strong motion
• 10 Seismic code development
• 11 Reinforced concrete analysis
• 12 Steel and masonry structures
• 13 Dampers, dissipators and isolators
• 14 Foundations and buried structures
• 15 Poster
• Author index