Full Scale Field Blast Tests on Reinforced Concrete Residential Buildings – From Theory to Practice

Abstract

The spread of terror threats aimed against built up urban areas has grown considerably during the years and attracts the attention and concern of many countries. The severity and potential danger of an extreme blast event in an urban area and especially in the proximity of buildings was demonstrated most severely in past events. Many countries, including Israel, are facing different threats of war and terror. Therefore, the Israeli Home Front Command (IHFC) is continuously engaged in theoretical and experimental research activities that are related to the response of civilian buildings to these threats. This paper focuses on blast pressure which is a major effect of these threats. The experience gained in recent years, in relation to the structural response of RC buildings, with emphasis on residential buildings that are subjected to blast loads, can be very helpful in the development of improved requirements and guidelines for design of such buildings, aimed mainly at reducing of the damage, and taking measures for damage localization in an attempt to reduce the occurrence probability of a progressive collapse of these buildings. The aforementioned experiences combine lessons learnt from different accidental events with the results of continuous research on major topics of blast response, including theoretical and experimental studies. Controlled experimental studies in general and full scale field tests in particular are most important and educative in these aspects. This paper describes the basic ideas behind full scale field blast tests aimed at studying the blast resistance and the response of reinforced concrete residential buildings and of various structural and nonstructural components that are incorporated in these buildings. Producing controlled blast loads of different intensities in the vicinity of the tested buildings enables identification of the structural elements' response at different damage levels, as well as at their ultimate state. It also enables to follow the overall response of multistory buildings to blast loading and assess their vulnerability to progressive collapse. This paper aims at addressing the full scale field tests of buildings subjected to blast, discussing some basic concepts and presenting some full scale field blast tests that had been performed in recent years. These tests have been performed by the IHFC, in cooperation with the National Building Research Institute (NBRI) at Technion-Israel Institute of Technology and partly with international research laboratories partners. This presentation aims at providing some insight into full scale field blast tests in general with some emphasis on a 5 story reinforced concrete residential building that was heavily instrumented with more than 200 gauges, including pressure, acceleration and strain gauges. The measured signals provide valuable information on the dynamic response of the tested structure that can be compared with predictions of its response made by different computational tools. The main objective of the present paper is to overview the potential benefits of field blast tests and to describe the ongoing studies. The detailed description and in depth analysis of any single test is beyond the scope of this paper, and is a subject matter for complementary specific papers in this field of blast response of reinforced concrete structures.