دانلود رایگان مقاله انگلیسی تحقیق و تمرین در فروپاشی تصاعدی و استحکام ساختار سازه در قرن بیست و یکم - الزویر 2018

ABSTRACT

Extreme events (i.e. terrorist attacks, vehicle impacts, explosions, etc.) often cause local damage to building structures and pose a serious threat when one or more vertical load-bearing components fail, leading to the progressive collapse of the entire structure or a large part of it. Since the beginning of the 21st century there has been growing interest in the risks associated with extreme events, especially after the attacks on the Alfred P. Murrah Federal Building in Oklahoma in 1995 and on the World Trade Center in New York in 2001. The accent is now on achieving resilient buildings that can remain operational after such an event, especially when they form part of critical infrastructures, are occupied by a large number of people, or are open to the public. This paper presents an ambitious review that describes all the main advances that have taken place since the beginning of the 21st century in the field of progressive collapse and robustness of buildings. Widely diverse aspects are dealt with, including: (1) a collection of conceptual definitions, (2) bibliometric details, (3) the present situation and evolution of codes and design recommendations, (4) quantification of robustness, (5) assessing the risk of progressive collapse, (6) experimental tests, (7) numerical modelling, and (8) research needs. Considering the comprehensive range of these aspects, this paper could be of great use to professionals and researchers who intend to enter the field of the progressive collapse of building structures and also to other experts who require an extensive and up-to-date view of this topic.

 Conclusions and needs

This paper presents an ambitious review of the most significant advances in the field of the progressive collapse of structures this century. It has been shown that recent years have seen considerable progress in this field, responding to the present need for robust buildings able to withstand extreme events without collapsing, and even resilient buildings that can remain operational after an extreme event (case of critical and strategic structures). New codes and design recommendations have been brought out, while those already existing have been adapted to allow for the latest advances. In addition, the scientific community, engineers and architects are now fully aware of the need for resilient buildings. Nevertheless, there is still a long way to go, there are still some areas that require deeper study and others that need to be studied for the first time. Based on the results of this review, the present and future needs in the field of progressive collapse and robustness of building structures can be defined as follows:

(a) Precast concrete construction. To date, most studies on progressive collapse have been carried out on cast-in-place concrete and steel or composite structures. It is noteworthy that structures composed of precast elements are becoming more frequent in critical infrastructures and public buildings like hospitals, passenger terminals, power plants, schools, administrative buildings, shopping centres, and sports centres. Although some progress has been made in the field of precast construction by means of lab tests on sub-assemblages [188–193], there is still a lot of work to be done and the scientific community must give more attention to this type of construction. For example, at the present time no studies are available on frames and complete buildings of this type, or on macromodels of beam-column joints, as has been done in the case of cast-in-place concrete, steel and composite structures.