PSI - Issue 44

Fabio Mazza et al. / Procedia Structural Integrity 44 (2023) 147–154

152

Fabio Mazza et al. / Structural Integrity Procedia 00 (2022) 000–000

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backed sheet vinyl flooring, with static ( µ s =0.056) and dynamic ( µ k =0.045) friction coefficients provided within the Blind Contest input data packet. Dimensions, mass m and height of centre of gravity h G are summarised in Table 3. A MATLAB algorithm is developed to solve the equations of motions, adopting the Runge-Kutta Ordinary Differential Equations (ODE) solver (MATLAB (2018)). 4. N umerical results 4.1. Fixed-base building: medical equipment and partition wall response Functional equipment and partitions damage evolution is discretised into different sets of damage states (DSs). Numerical and empirical thresholds based on visible damage are defined in the Blind Prediction submission package (Blind Prediction Contest (2020)). Experimental results referred to low and medium intensity seismic events are compared to maximum rocking angle and sliding displacements deriving from rigid body motion analysis of incubator and dialysis machine. Motion typology is perfectly replicated by simplified equations of motion solution (Figures 5a,b). Peak values from rocking and sliding time histories provide safe-sided estimations of damage states (Figures 5d,e). In addition, preliminary results obtained for a third medical component, a surgical bed, are shown in Figure 5c. Damage states of the monitored partition wall are based on combined IP-OOP damage. IP or OOP failures correspond to DS3. DS2 is reached when the IP second branch is exceeded and/or after OOP cracking of both the double-layer gypsum panels. An elastic IP and OOP behaviour is associated to DS0, slight cracking to DS1. Experimental DSs tend to be in good agreement with numerical ones and, again, on the safe side (Figure 5f). Missing experimental DSs are noticeable in Figure 5d and Figure 5f, due to insufficient tracking data (Blind Prediction Contest (2020)).

(a) Incubator motion typology.

(b) Dialysis machine motion typology.

(c) Surgical bed damage states.

(d) Incubator damage states.

(e) Dialysis machine damage states.

(f) Partition wall damage states.

Figure 5. Rigid body motion typology (medical equipment) and damage states (medical equipment, partition).

4.2. Fixed-base building: nonstructural acceleration amplification factors

Dynamic amplification factor (DAF) can be evaluated as the ratio between the maximum nonstructural component absolute acceleration and the reference floor one. Peak values and amplification factor time histories referred to piping systems below Level 3 and sand-filled tanks above Level 4 were provided after Blind prediction contest Phase II in a graphical format, for low and medium intensity ground motions (JMA_Kobe 16% and 50%, OS-2 20% and 50%). DAFs are evaluated for each seismic direction separately, if two or more seismic components are simultaneously applied. Only maximum values and their time location are considered, due to the lack of numerical time histories. Amplification factors seem to be slightly underestimated by predictions in the case of piping (Figure 6a). Little