Learning from disaster to prevent progressive collapse

When the Alfred P. Murrah federal building in Oklahoma City was destroyed by a terrorist bomb in 1995, its progressive collapse compounded the blast damage and increased loss of life. Subsequent studies suggested ways that structural design changes might have improved the building's performance as well as that of other buildings subject to similar attacks. This paper reports on how the original structural design could be virtually ‘retrofitted’ to meet current codes for areas of high seismicity. Three different strengthening schemes are analysed for their responses to the 1995 blast, two of which substantially reduce the degree of blast-induced damage and subsequent progressive collapse.