Influence of Vibrational Impacts on the Bell Towers and the Problem of Safety

Abstract

Due to reconstruction and restoration of the original guise of the landmarked buildings the investigators are facing the problems of assessing possible adverse consequences of such sorts of work in the recent years. The most problematic are the works requiring dismantling of the bearing and fencing structures built into original scheme. This article gives consideration to the ways of solving a problem of ensuring safety of buildings and structures in use provided their operating conditions have changed (e.g. the assessment of possible consequences of bells installation on the steeples of St. Isaac's Cathedral is presented). The measurements of vibrations with simultaneous assessment of robustness and bearing capability of the brickwork have shown that the vibrational impact of chimes of heavy bells cannot adversely affect the bearing structures of the bell towers. However, there is always a risk of such adverse effect on the structure of the bell tower and stability of soils at its base. A danger emerges not because of significant settlements, but rather due to irregularity owing to inhomogeneity of soil. The obtained assessments of settlements show that they cannot be ignored and it is reasonable to perform an annual leveling check of settlements of foundation or base of the bell tower It is offered, therefore, to carry out investigation before the beginning of reconstruction using the structure model, which makes it possible to give consideration to the impact of «new» loads to exclude any possible emergency situation at the objects being reconstructed.