PSI - Issue 62

Carlo Pettorruso et al. / Procedia Structural Integrity 62 (2024) 677–684 Carlo Pettorruso/ Structural Integrity Procedia 00 (2019) 000 – 000

684

8

Table 6 Results

a target m/s 2 1,67 1,02 0,88 1,67 1,02 0,59 1,67 1,02 0,59

a AsBuilt

a ES

Condition I

Condition II

Height

Seismic zone

m

m/s 2 9,14 6,66 2,32 5,97 3,33 1,16 2,71 1,54 0,52

m/s 2 0,80 1,25 0,93 0,59 0,81 0,46 0,26 0,37 0,21

[-]

[-]

5

Necessary Necessary Necessary Necessary Necessary Necessary Necessary Necessary

Suitable

Reggio Calabria

10 20

Not Suitable Not Suitable

5

Suitable Suitable Suitable Suitable Suitable Suitable

Sirmione

10 20

5

Pavia

10 20

Not Necessary

Retrofitting is necessary in each scenario and for all the heights considered, but for 20 m high piers in seismic zone 3. Under weak ground accelerations and with flexible piers, there is no need of seismic upgrade, because the seismic demand does not exceed the inherent capacity of the pier. In contrast, in two cases, relevant to seismic zone 1, the capacity of the pier section has not enough resources to resist the seismic action associated to the weight of the substructure only, and the bridge is not suitable for seismic isolation. A different retrofit based on strengthening must be proposed. 5. Conclusions The paper presents a fast procedure for assessing the suitability of seismic mitigation in bridges. Specifically, this procedure consists of an initial assessment of the available structural resources and the margins of bridge retrofit without substructure stiffening. This procedure is applied in this paper to a parametric study, pointing out different outcomes in cases of different pier heights and different seismic scenarios. CEN European Committee for Standardization: Brussels, Belgium, 2004. EN 1998-1 Eurocode 8: Design of Structures for Earthquake Resistance — Part 1: General Rules, Seismic Actions and Rules for Buildings. CEN European Committee for Standardization: Brussels, Belgium, 2004. EN 1998-2 Eurocode 8: Design of Structures for Earthquake Resistance — Part 2: Bridges. Circolare 21 gennaio 2019, n. 7 C.S.LL.PP. Istruzioni per l’applicazione dell’«Aggiornamento delle “Norme tecniche per le costruzioni”» di cui al decreto ministeriale 17 gennaio 2018, Roma; (in Italian) Delgado et al, 2009. Shear effects on hollow section piers under seismic actions: Experimental and numerical analysis. Bulletin of Earthquake Engineering, Volume 7, Issue 2, Pages 377 – 389, 10.1007/s10518-008-9098-x Italian Building Code. Technical Recommendations for Buildings — D.M. 17/02/2018. Italian Building Code: Rome, Italy, 2018. (In Italian) Jin Z., Huang B., Pei S., Zhamg Y.(2021), “Energy -based additional damping on bridges to account for vehicle-bridge interaction” Engineering Structures 229-n111637 Nishi, T. (2004). “Recent advances on application of elastomeric isolators for bridges and buildings in Japan.” Symposium of International Rubber Conference, Bangkok, Thailand, 91-98. Pinto et al, 2003. Cyclic tests on large-scale models of existing bridge piers with rectangular hollow cross-section. Earthquake Engineering and Structural Dynamics, Volume 32, Issue 13, Pages 1995 – 2012, 10.1002/eqe.311 References