Rocking of freestanding objects: theoretical and experimental comparisons

Abstract

The methodical study of safeguard of artistic heritage and other devices subjected to earthquake and, in general, to time-dependent forces has considerably spreaded in the last years, thus increasing researchers' interest in problems concerning motions of rigid objects simply supported on a base plane. The behaviour of piece of equipments, statues, storage tanks, or even tall buildings has been in fact studied as that of rigid bodies with relation to different base excitations. In some cases, the possibility of influencing the quality of motion can be a strong tool to reduce vulnerability, like in the cases in which rocking motion is to be avoided and sliding motion is welcome. This paper focuses the attention on this last problem. This is the same large class of both non-structural and structural elements that can lose their functionality because of earthquake motions. The results of numerical modelling of sliding and rocking motion in presence of both different excitations and mechanical parameters are presented and compared with experimental data performed by the authors. The results developed are in good agreement with the laboratory tests, and this assures the reliability of both the analytical procedure and the determination of the parameters involved.

Subsurface Detection of Shallow Targets by Undersampled Multifrequency Data and a Non-Cooperative Source

“…The problem of detecting buried targets through electromagnetic waves is a classical inverse scattering problem which is relevant in a number of different applications [1,2] such as civil engineering diagnostics [3][4][5][6][7][8][9], archaeological and geophysical prospecting [10,11], cultural heritage monitoring [12,13], mines and IEDs (improvised explosive devices) detection [14], only to mention a few of them. Electromagnetic waves at the microwave spectrum allow to get high resolution.…”

Seismic Protection of Statues. A Case Study

“…The system has two degrees of freedom, namely the rotation  (clockwise positive) of block 2 (statue) and the centroid position 1 G x of block 1 (pedestal). Assuming 1 m and 2 m masses of the two blocks whose center of masses are 1 G and 2 G , 12 Mmm  is the total mass of the system and ( ( ), ( )) gg x t y t are the components of the base motion. Let The hypothesis of sliding motion for the statue lead to null vertical component of its relative motion with respect to the base.…”

“…In every case the response under earthquake of the aforementioned artefacts significantly depends on both the dynamic characteristics of the objects themselves and those of the building in which they are arranged [8,9], as well as the input ground motion [10,11]. Other aspects to take into account are the friction coefficient between the block and the base [12] and the geometry of the object [13,14]. The problem becomes more complex when the behaviour of two stacked rigid bodies is examined: the highly nonlinear formulation needs some simplifying assumptions [15,16].…”

Overturning risk of furniture in earthquake-affected areas

“…Boroschek and Iruretagoyena (2006) proposed an approach to control the overturning direction. Gesualdo et al (2018a, 2018b), numerically and experimentally, investigated the seismic protection of historic objects in museums and special equipment. The role of friction is also deepened in the work of Gesualdo et al (2018c) and Monaco et al (2014).…”