Underground blast effects on structural pounding

In the present study, actual three-dimensional structures are converted into a stick model of multi degree of-freedom(MDOF) systems for understanding the macro-behavior of structures. The study investigates the performance of three closely spaced, adjacent G+10, fixed-base MDOF systems with the mass aligned at the same levels and subjected to accidental underground blast loading. The acceleration time history of underground blast loading is generated based on past empirical relationships. The blast charge weight varies from 10 to 75 t while keeping the charge distance constant(R=100 m). The entire formulation is solved with the MATLAB solver, using the state space form solution. Three cases are considered, based on changing the position of the three stick systems. The first case considered left building rigid, middle building moderate rigid, and right building flexible. The second assumed left building flexible, middle building rigid, and right building moderate rigid. The third examined the left building as moderate rigid, the middle building as flexible, and the right building rigid. An analysis of the results shows that the arrangement with low stiffness, high stiffness, and moderately stiff buildings placed to the left, middle, and right side, respectively, yields minimum structural response when compared to the other two combinations.