PSI - Issue 44

Andrea Dall’Asta et al. / Procedia Structural Integrity 44 (2023) 862–869 A. Dall’Asta et al./ Structural Integrity Procedia 00 (2022) 000–000

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Displacement transducer

Plan view

Inductive sensor

Red = fixed to the base Blue = fixed to the isolated structure

Inductive sensor

Displacement transducer

Section view

Inductive sensor

Displacement transducer

Displacement transducer

Displacement transducer

Fig. 3 Configuration and installation of displacement sensors at level 0 below isolation.

4. Preliminary analysis of the experimental results The experimental tests were performed when the structures were completed, without partitions, external walls, architectural elements, and technological equipment. The total estimated mass of the structures above the isolators was 4633 tons. Two types of push-and-release tests were made: 1) loading and unloading without sudden release, hereafter called quasi-static (S) tests; 2) loading up to the rupture of the fuse followed by a sudden release, hereafter called dynamic (D) tests. The sequence of the tests is reported in Table 1, with indication of the starting time, the duration of the loading phase for quasi-static and dynamic tests, the maximum horizontal force and displacement. The amplitude of displacements ranged from 109.4 mm to 284.6 mm, being the higher value close to the maximum displacement of the isolation system expected at the CLS. In the first test no displacements were recorded as the applied horizontal force was lower than the breakaway friction force. The environmental conditions during tests are reported in Table 2. Tests on the 3 rd of July were interrupted just before 17:00 due to a violent thunderstorm following a sunny and hot day. The missing data at the South corner (last five rows of the second test day) was caused by a malfunction in the sensor. It is noted that the variation of temperature during tests at the isolation level was small (2 to 4 Celsius degrees) while larger variations (almost 6 Celsius degrees) were observed in the superstructure.