PSI - Issue 78

Elisabetta Bersanetti et al. / Procedia Structural Integrity 78 (2026) 372–378

376

The design includes 133 HDRB (High-Damping Rubber Bearings) elastomeric isolators, each 200 mm high and 550 mm in diameter, with an equivalent damping ratio of 12%, and 167 sliding devices capable of 25 cm of displacement. The maximum displacements under SLC (Limit State for Serviceability) conditions remain within 22 cm, and no global torsional effects are observed. Additional sliding devices are required to manage the loads from elevators and two boiler rooms, which are stiffly connected to the superstructure. The proposed layout ensures alignment of the centers of mass and stiffness, resulting in a principal period of 2.85 – 2.90 seconds.

Fig.5 Typical load deflection plot of HDRB

Table 1. Modal analysis results

Seismic Dir. 1

SeismicDir. 2

Masses

Perc.

Masses

Perc.

Frequency and Modal Masses

Excited

32885.33 99.99

32884.6 99.99

Total

32886.89

32886.89

Mode Frequency N.ro (rad/sec)

Period Damping Sd/g

Sd/g

Sd/g SLV 0,048 0,048 0,055 0,447 0,493 0,515 0,528 0,534 0,534 0,534

Sd/g Modal Mass Perc.

Modal Mass Perc.

(sec)

Mod(%)

SLO SLD

SLC

Ecc. (t)

Ecc. (t) 125,87

99

1 2 3 4 5 6 7 8 9

2,168 2,181 2,334

2,89845 2,88072 2,69200 0,52458 0,47613 0,45548 0,44414 0,40512 0,38618 0,35065

11,3 11,5 11,5

0,015 0,015 0,017 0,134 0,147 0,154 0,158 0,172 0,172 0,172

0,020 0,020 0,023 0,174 0,192 0,201 0,206 0,220 0,220 0,220

0,063 0,064 0,073 0,557 0,613 0,641 0,652 0,652 0,652 0,652

32534,88

0

98

165,51 134,51

1 0 0 0 0 0 0 0 0

32133,64

596,61

2 0 0 0 0 0 0 0

11,978 13,196 13,795 14,147 15,509 16,270 17,919

5,0 5,0 5,0 5,0 5,0 5,0 5,0

48,51

0,02

0,04 1,56 0,27 0,05 0,00 0,00

24,26

0,20 2,93 1,06 0,00 0,00

10

b

a

Fig.6 Displacement SLC of isolation system for seismic forces a) 100% direction X - b) 100% direction Y

Table 2: Isolators and Sliders results

ISOLATORS

N - Seismic

N - Static

Displacement

Maximum Values and Mean Values

(kg)

(kg)

mm 218

-250484

-159766

MAX