Development Of Seismic Codes Research Articles

A Comparative Study of MCDM Methods Integrated with Rapid Visual Seismic Vulnerability Assessment of Existing RC Structures

Recently, the demand for residence and usage of urban infrastructure has been increased, thereby resulting in the elevation of risk levels of human lives over natural calamities. The occupancy demand has rapidly increased the construction rate, whereas the inadequate design of structures prone to more vulnerability. Buildings constructed before the development of seismic codes have an additional susceptibility to earthquake vibrations. The structural collapse causes an economic loss as well as setbacks for human lives. An application of different theoretical methods to analyze the structural behavior is expensive and time-consuming. Therefore, introducing a rapid vulnerability assessment method to check structural performances is necessary for future developments. The process, as mentioned earlier, is known as Rapid Visual Screening (RVS). This technique has been generated to identify, inventory, and screen structures that are potentially hazardous. Sometimes, poor construction quality does not provide some of the required parameters; in this case, the RVS process turns into a tedious scenario. Hence, to tackle such a situation, multiple-criteria decision-making (MCDM) methods for the seismic vulnerability assessment opens a new gateway. The different parameters required by RVS can be taken in MCDM. MCDM evaluates multiple conflicting criteria in decision making in several fields. This paper has aimed to bridge the gap between RVS and MCDM. Furthermore, to define the correlation between these techniques, implementation of the methodologies from Indian, Turkish, and Federal Emergency Management Agency (FEMA) codes has been done. The effects of seismic vulnerability of structures have been observed and compared.

Effects of Earthquake Faulting on Civil Engineering Structures

Ground motion characteristics, deformation and surface breaks of earthquakes depend upon the causative faults. Their effects on the seismic design of engineering structures are almost not considered in the present codes of design although there are attempts to include in some countries (i.e. USA, Japan, Taiwan, and Turkey). In this study, the authors first describe ground motions, crustal deformation and surface break observations caused by earthquakes having different faulting mechanism. Then some laboratory experiments were carried out to simulate the motions during normal and thrust faulting and their effects on model structures. And then, the effects of surface ruptures and deformations due to earthquake faulting on the response and stability engineering structures through observations in recent great earthquakes are presented. Finally, some recommendations for the design of structures with the consideration of permanent ground deformation in addition to ground shaking, which may be used in the development of seismic codes incorporating the effect of permanent deformation on structures, are proposed.

State-of-the-Art Review on Seismic Design of Steel Structures

This state-of-the-art review provides an overview of the evolution of seismic design requirements for main steel building seismic force–resisting systems, as driven by new developments, the 1994 Northridge, California, earthquake, and changes in earthquake engineering practice in the United States. Important aspects of these systems in terms of ductility design and capacity design are highlighted. Recent developments in practice related to innovative systems are touched upon. The work presented here is intended to provide the reader with an appreciation of why the current seismic design requirements for steel structures are as framed, highlighting in the process several unresolved issues and inconsistencies that will require attention in future research. Implications of the Christchurch, New Zealand, rebuilding after the 2010–2011 earthquakes there for future U.S. seismic code development are also presented.

Scenario based seismic re-qualification of caisson supported major bridges – A case study of Saraighat Bridge

Many major river bridges were constructed in highly active seismic areas of India much before the seismic code development. Bridges are lifelines infrastructure and as a result, it is necessary to requalify/reasses these structures in the light of the new and improved understanding of seismic resistant design philosophies. The aim of the paper is to develop a simplified methodology to carry out scenario based seismic requalification of major river bridges supported on caisson foundations (also known as Well Foundation). An example problem of Saraighat Bridge located in highly active Himalayan seismic zone is considered to demonstrate the application of the methodology. Field investigation and advanced laboratory tests on soil samples from the bridge site were carried out. The test results reveal that the soil is susceptible to liquefaction and as a result, soil structure interaction analyses are carried out. It is shown that good performance of these type of bridges depend on the displacement response of the pier head so as not to cause unseating of the decks. It is concluded, owing to the large stiffness of the foundations, bridges supported on caisson foundations may not be adversely affected by liquefaction induced effects.

Expanded papers from an international workshop on performance-based design—concepts and implementation

An international workshop on performance-based design was held in Bled, Slovenia, on June 28–July 1, 2004. This workshop provided a valuable forum for the exchange of research results and design practice ideas on issues important for seismic risk reduction and the development of performance-based earthquake engineering concepts. The theme of the workshop was to assess the state of knowledge and practice related to performance-based design and to identify challenges that need to be addressed so that progress in research and implementation in engineering practice can be accelerated and a common foundation can be established on which to base the various approaches advocated in different countries. At the workshop, 45 invited participants and 12 observers from 14 countries addressed the following topics in four working groups: loss estimation, fragility and vulnerability, and impact on risk management; implementation in engineering practice; performance-based design concepts; and integration of experimental and analytical simulations. The workshop has led to a greater understanding of many of the issues involved in performance-based design, and much progress has been made in the development of concepts and procedures suitable for implementation in engineering practice. Nevertheless, many issues remain unresolved and additional research and studies are needed to implement rigorous performance-based design with confidence. Performance-based design concepts provide a suitable framework for future seismic code development. Common interests exist among researchers and practitioners of the countries represented at the workshop. Progress in research and implementation in engineering practice can be accelerated by the international dialog on new ideas and concepts. Cooperative research on issues of common interest should be encouraged. The participants recognize that performance-based design has many facets and may take on very different meaning and approaches depending on prevailing economic and societal priorities. Nevertheless, by continuing the international dialog, a common foundation can be established on which to base the various approaches advocated in different countries. An urgent need exists for worldwide sharing of data obtained from experimental and analytical studies and from field measurements taken during earthquakes. A protocol for international data sharing should be developed and efforts should be initiated for the creation of a worldwide data repository. In order to accelerate the transfer of knowledge from researchers to engineering practice, a need exists for incorporating performance-based design concepts and reliability theory into educational curricula. Recognizing the benefits of the exchange of ideas that occurred at the workshop, international gatherings should be held on a periodic basis to share information on the development of performance-based design. To further increase the impact of the work discussed in Bled, the workshop participants were encouraged to submit expanded versions of their papers to the Journal, provided they report on previously unpublished material appropriate for a journal publication. Submitted manuscripts have undergone the regular review process, which was handled by Anil K. Chopra. Seven papers, printed in this issue, have been accepted for publication. The full workshop proceedings, which contain 43 papers as well as the workshop resolutions, conclusions and recommendations, can be obtained from the Pacific Earthquake Engineering Research Center, 1301 South 46th Street, Richmond, CA 94804, U.S.A. (info@nisee.berkeley.edu).

Seismic design implications of revisions to the National Building Code of Canada

This paper begins with a brief introduction to Canadian seismicity and the history of seismic code development in Canada; a summary of major changes planned for the 2005 edition of the National Building Code of Canada follows. Areas of major change include seismic hazard, site effects, irregularities, force reduction factors and methods of analysis (dynamic analysis now being preferred). The implications of the proposed changes are presented in terms of impact on seismic design force for several structural systems located in regions of high, moderate and low seismicity; implications for seismic level of protection and the seismic design process are also discussed. The paper concludes with a discussion of ongoing seismic code development issues.

Seismic Design Provisions in U.S. Codes and Standards: A Look Back and Ahead

The seismic code development process that was in place in the United States for many decades is undergoing dramatic changes. These changes and their possible impact on seismic design provisions for precast concrete structures in the United States model codes are discussed.

Seismic code development for steel structures

This paper discusses revisions proposed by the Structural Engineers Association of California for the seismic design of steel structures. Several of the new provisions are drastic departures from current practice and are expected to have a considerable impact on design. The proposed changes are discussed from the perspectives of the practising engineer, the researcher, and the committee that drafted the new provisions.