Blast loads (Luccioni et.al, 2003)

Explosive loads become issues that have received considerable attention in recent years which it’s can easily damage the buildings that within the explosion. Hence, new developments in integrated computer hydro codes, such as AUTODYN software were used for this research as a tool to carry out for the numerical analysis.

The analysis of structural collapse of the building was performed in two stages. The first part of the analysis consists on the simulation of the explosion itself from the detonation instant and the second part consists on the analysis of the effect and interaction with the building of the blast wave generated by the explosion. The load that produced by air blast wave was only considered in the analysis and the ground motion generated by the explosion was not taken into account in this research.

An illustration of the role played by the interaction of the blast wave with the building, the propagation of the blast wave in a building without walls is compared with the propagation of the same blast wave in the actual building with walls as shown as below.

Effect of the walls in the blast wave propagation. (a) building without walls, (b) building with walls.

The results obtained for an explosive load of 400kg of TNT located 1m above the ground level, 1m inside the entrance hall and 1m to the right of the axis of the building are described as bellow:

Evolution of damage produced by the explosion. (a) 0.75ms, (b) 254ms, (c) 378ms (d)1.35ms and (e)2.46ms

Comparison with actual damage

The distribution of the remains of the demolition with those registered in the actual building.

The numerical simulation reproduces the fall of the front slabs that resulted hanging from the back part of the building.

Slabs hanging from the highest stages

View of the reinforced concrete frames that remained after the explosion.

 Remaining frames

The comparison between actual damage and that numerically obtained proves that the simplifying assumptions made for the structure and materials are allowable for this type of analysis and nowadays represent the only way to successfully run a complete collapse analysis of an entire building.