سال انتشار: ۱۳۸۴

محل انتشار: دومین کنفرانس بین المللی بتن و توسعه

تعداد صفحات: ۹

نویسنده(ها):

Paolo Emilio Pinto – University of Rome “La Sapienza”Rome, Italy

چکیده:

On February 11th, 2005, Part 3 of Eurocode 8 (EC8/3,[1]) has been unanimously positively voted by the representatives of the 23 countries adhering to CEN (Comité Européen de Normalisation), which include both EU and EFTA member countries. The document is entirely new with respect to a previous draft, which was issued in the ’90s, and it took only about three years to be completed and to meet with general acceptance. This is quite a remarkable fact, if one considers that for documents of much less controversial nature, as for example Part 1 of EC8, which deals with the design of new structures, it took about ten years to reach the consensus for passing from the 1994 Pre-Standard version to the present status of a European Standard. The reason for this apparent success may not be sought so much in the quality of the document, documents of truly high quality take often years of minute discussions to get approved, but rather in the ever increasing awareness of the urgent need of doing something in the direction of alleviating the problem of existing structures.The second half of the past century has in fact witnessed an accelerating process of growth of urban areas, which has taken place worldwide with little, if any, consideration of the existence of a serious seismic hazard and also, quite frequently, according to sub-standard design and construction practices. The full realisation of the gravity of the situation in terms of expected human and economic losses is a relatively recent fact, dating back essentially to the economically disastrous events in California at the end of the eighties (Loma Prieta, 1989) and reinforced by the following equally disastrous events in Japan (1995), Turkey (1999), etc. There are no quick fixes to the present situation: the push towards urbanisation and industrial concentration will continue to grow and in a few cases only this process will be riskcontrolled. Due to the very large economic resources required to reduce the present risk to more acceptable levels, long-term planning is the only viable approach. In this context, the availability of effective technical regulations for the seismic assessment acquires a critical role, in that it leads to a drastic reduction of the arbitrariness in the diagnosis of the capacity of the structures in their present state, and it requires an analytical demonstration of the necessity and of the effectiveness of the proposed interventions.