PSI - Issue 44

Maria Teresa De Risi et al. / Procedia Structural Integrity 44 (2023) 958–965 De Risi, Del Gaudio, Scala, Verderame/ Structural Integrity Procedia 00 (2022) 000–000

964

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Resulting total unit cost per square meter (tc) varies from about 160 to 170 €/m 2 (see Table 2); the cost strictly related to the structural intervention only (i.e., CAM application only) represents about 55% of that tc. Fig. 7b shows the unit cost tc divided by the SI increment at SD LS (ΔSI) depending on SI SD,ante , thus providing the unit cost to spend aiming at 1% increment of ΔSI. The clear decreasing trend is mainly due to the evidence that for higher PGA D , generally associated to lower values of SI SD,ante , ΔSI produced by the implemented intervention is lower (Fig. 7a); thus tc/ΔSI results higher. Finally, it can be noted from Table 2 that when costs for implementation of safety provisions (2.5% of tc), VAT (10%), and technical costs (12.5% of tc plus VAT and taxes) are added to the above-defined tc, a total of about 200 euro/m 2 is obtained, corresponding to 17-18% of the cost of reconstruction “C R ” (the latter assumed equal to 1192 €/m 2 Di Ludovico et al., 2017). Such a cost results certainly covered by the available contribution for the reduction of seismic risk of residential buildings recently funded by Italian government (D.M. 2017), in the hypothesis that each floor has two residential units (r.u.) (namely, total contribution equal to 96000 €/r.u. × 2r.u. × Ns).

(c)

(d)

(a)

(b)

Fig. 6. IS SD for strengthened buildings: a) 2-storey; b) 4-storey; ΔIS SD : c) 2-storey; d) 4-storey

Table 2. Total cost for local interventions

TC +V.A.T.+ safety + technical cost

% of total contribution (DM 2017)

cost for structural intervention only

Ns design objective

total cost (TC)

%C R

-

-

k€

€/m 2 €/m 3 k€

%tot

k€

€/m 2 217.9 207.7

€/m 3 72.6 69.2

%

%

2 min(1 st DF; 1 st JF "C") 70.8 169.4 56.5 40.0 4 min(1 st DF; 1 st JF "C") 135.0 161.5 53.8 72.8

56 54

91.1

24 23

18 17

173.7

0 2 4 6 8 10

16

4-storey 2-storey

(a)

(b)

4-storey 2-storey

y = 1.28 x -0.78 R² = 0.90

12

0 tc / (100 ΔSI) (€/m 2 ) 4 8

ΔSI

y = 0.29x -0.55 R² = 0.59

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.1

0.2

0.3

0.4

PGA D,SD (g)

SI SD,ante

Fig. 7. a) ΔSI depending on the PGA demand at SD LS; b) unit cost (tc) required to 1% increment of ΔSI depending on the SI SD,ante

6. Conclusions Two- and four-story gravity load designed pre-70 RC buildings are analyzed via pushover analysis to assess their seismic performance in a code-based approach (D.M. 2018) in all the “non-seismic” sites in Italy before ‘70. Shear