PSI - Issue 78

Graziano Leoni et al. / Procedia Structural Integrity 78 (2026) 1443–1450

1448

The mobile table moves together with actuators, the parking frame, accumulators, and associated piping and cabling. Steel rails on trench walls guide horizontal actuators, allowing free adjustment without dedicated attachment points. Based on design assumptions and specifications, both shake tables, supplied by SERVOTEST, can simultaneously reach the performance levels summarized in Table 1. The system reproduces historic and synthetic seismic events, including the 1995 Kobe earthquake (Japan) and the 1940 El Centro earthquake (USA), as well as artificial accelerograms compatible with AC156 criteria for seismic certification of non-structural components.

Table 1. Shake-tables features. Parameter

Performance

Peak displacement ±28 cm horizontal ±15 cm vertical Peak velocity (continuous sinusoidal excitation, full payload) ±90 cm/s horizontal ±60 cm/s vertical Peak velocity (≥3 cycles, full payload) ±120 cm/s horizontal ±100 cm/s vertical Peak acceleration ±1.4 g horizontal ±1.2 g vertical Operational frequency range

0.1Hz – 50 Hz for full payload

Natural frequency of table

>120Hz

Input signal types Control system

sinusoidal, impulsive, seismic, random

digital servo-hydraulic

The system is equipped with a comprehensive network of sensors to monitor the response at the center of mass, at table edges, and on all actuators and servo valves. Performance curves for acceleration, velocity, and displacement are defined for both horizontal and vertical directions, allowing precise evaluation of the system under full payload conditions (Fig. 6 – 7).

1.2m/s

Continuos vel dual tables 0.90m/s

Fig. 6. Horizontal performance curves at 100% payload.