Proceedings home preface contents authors keywords copyright reference ©2012 Civil-Comp Ltd				Paper 274 The Collapse of a Skylight Shell Structure caused by a Blast A. Angotzi1, A. Mussi1, E. Trolese2, M. Zanchin2, R. Gori3 and A. Mastropasqua3 1Arup Italy srl, Milan, Italy 2Mastropasqua-Zanchin & Associates Structural Engineering, Treviso-Udine, Italy 3Department of Civil, Environmental and Architectural Engineering (DCEAE), Padua University, Italy Keywords: non-linear numerical analyses, blast event, steel structures, skylight system. full paper (pdf) - reference Following the failures caused by explosions, that in recent years have involved both civil and military buildings, the dimensioning of structures subjected to blast forces and the verification of the resistance to failure of one or more structural elements have become of utmost importance during the design phase. This paper therefore evaluates suitable considerations, with reference to a specific structural system currently under construction; the system, a skylight shell structure designed by means of glass envelope and structural steel members, has the dimensions of 52.50 m and 40.00 m respectively for the maximum and minimum geometrical axis, and a span ratio of 6.75%. For assessing design criteria, several blast-wave signals were obtained, for the detonation effects, in terms of peak reflected pressure, shockwave arrival time, duration of the positive phase, duration of the negative phase, and negative peak reflected pressure. These were determined assuming, conventionally, a direct pressure relationship using the polynomial equations of Kingery and Bulmash [1], which form the basis of the US manual TM5-1300 [2]. This assumption was enabled using the job technical specifications which considered the distance between the detonation point and the glass system, therefore ignoring the side-wall reflection effects. The non-linear time-history responses of the system were investigated by means of a finite element model, highlighting some valid indications of the hypotheses of the possible locations of plastic mechanisms which were responsible for the progressive structural failure. Furthermore, some indications of the damping response of the material and structural connections were obtained, following a comparison between a hypothetical non-linear elastic behaviour (with no energy dissipation) of the material and the realistic non-linear elastic-plastic response (with energy dissipation). References 1 C.N. Kingery, G. Bulmash, "Airblast Parameters from TNT Spherical Air Burst and Hemispherical Surface Burst", ARBRL-TR-02555, Ballistic Research Laboratory, Aberdeen Proving Ground, MD, 1984. 2 Army TM-5-1300, Navi Navfac P-397, Air Force AFR 88-22, "Structures To Resist The Effects Of Accidental Explosions", 1990.