Dynamic behaviour of a belfry caused by the swinging bells

Through non-destructive tests we have determined the dynamic characteristics of the wall belfry of Our Lady of the Carmen Church (Valencia, Spain). We explain the method applied to obtain these characteristics, knowing the spectrum response of the structure when one of the bells turns. After studying the bells, we have determined the fundamental magnitudes of their oscillatory movement: weight of bells, turn speed, unbalance and inertia. These values are necessary to determine the variable time forces that they introduce in the structure. Using a numerical model at real scale of this structure we have determined the least favourable dynamic amplification factor (DAF) and the resistant response of this tower in a quasi-static analysis for these forces.