Practical Methods For Increasing The BlastResistance Of Existing Buildings

Abstract

This paper includes the description of the recent Israeli R&D efforts (1991-1993) in researching, developing, testing and building practical strengthening measures for existing buildings, to increase their resistance against explosive effects. The strengthening measures refer to all types of building elements, sensitive to blast loadings, such as windows, doors, light roofs and weak ceilings, as constructed in normal unhardened buildings. The strengthening measures comprise additional means for improving the blast resistance of existing elements, as well as new blast-resistant elements, replacing the existing ones. The strengthening measures cost-effectiveness as well as their implementation are also discussed, in the frame of the Israeli practical experience. INTRODUCTION It was repeatedly found that normal buildings are severely damaged by blast loadings from nearby explosions. At larger distances, the most sensitive building components are the normal glass windows, which fail under low blast overpressures. At closer ranges, the doors in the building start failing, followed by light roofs and ceilings. As the blast level increases, normal brick and masonry walls fail and at close ranges the structural elements: columms, beams, etc. begin to feel the blast loadings. Following the lessons learned from observing the damages to many normal buildings in Tel Aviv, during the Iraqui Scud missiles attacks in 1991, the Israeli Home Front Command has embarked on a five-year research and development program (1991-1995) to test, develop and define strengthening measures for existing building components, to increase their blast resistance. THE TEST PROGRAM In 1991-1993 the test program included four full-scale tests series, performed in October 1991, April 1992, May 1992 and May 1993. The next full-scale tests are scheduled for June 1994. In the tests performed in 1991-1993, a total of 151 building elements were tested, as described in table no. 1. Transactions on the Built Environment vol 8, © 1994 WIT Press, www.witpress.com, ISSN 1743-3509 30 Structures under Shock and Impact TESTS DATE OCTOBER 1991 APRIL 1992 MAY 1992 MAY 1993 NUMBER OF EXPLOSIVE CHARGES