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Performance Base Design of the Messina Strait Bridge

Salvatore Marrocco

Performance Base Design of the Messina Strait Bridge.

Rel. Gian Paolo Cimellaro, Farhad Ansari. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Civile, 2025

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Abstract:

The main objective of this study is the development and dynamic analysis of a scaled prototype model of the Messina Strait Bridge under seismic loading. A physical model was constructed in the laboratory at a scale of 1/265. To simulate the soil-structure interaction (SSI), a spring-box system was designed and implemented, allowing the study of three different soil conditions: soft, medium, and hard soils. Additionally, the dynamic behavior of the bridge under damaged cable conditions was investigated. Finite Element Analysis was used to identify optimal sensor placement points, including Fiber Bragg Grating (FBG), Linear Variable Differential Transformers (LVDT), and accelerometers. However, the experimental verification of the model’s seismic response is still pending, as the software MIDAS Civil does not currently support the application of ground motions to damaged configurations. Despite this limitation, the numerical simulations revealed that cable damage leads to highly localized effects. Specifically, the adjacent suspenders to the broken one experienced a substantial increase in tension, while those farther away were only minimally affected. Similarly, vertical displacements were concentrated in the area surrounding the damaged suspender, and the tension in the main cables remained almost unchanged. DCR analysis showed that shorter suspenders tend to exhibit higher DCR values, indicating lower safety margins and a need for immediate replacement in case of damage. It was also observed that suspenders located on the opposite side of the bridge from the damage location were not influenced by the failure. The spring-box system proved effective in replicating the behavior of different soil conditions and highlighted the importance of modeling soil-structure interaction (SSI) when developing a FEM model. Neglecting SSI may lead to significant underestimation of the actual structural response. Finally, the results showed that softer soil conditions resulted in larger mid-span displacements, particularly in the case of near-fault ground motion (AQK), compared to far-fault motion (MTR). These findings emphasize the critical role of SSI in the seismic performance assessment of long-span suspension bridges.

Relatori: Gian Paolo Cimellaro, Farhad Ansari
Anno accademico: 2024/25
Tipo di pubblicazione: Elettronica
Numero di pagine: 94
Soggetti:
Corso di laurea: Corso di laurea magistrale in Ingegneria Civile
Classe di laurea: Nuovo ordinamento > Laurea magistrale > LM-23 - INGEGNERIA CIVILE
Aziende collaboratrici: University of Illinois at Chicago
URI: http://webthesis.biblio.polito.it/id/eprint/35879
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