Ocena negotovosti pri potresno povzročeni poškodbi cevovoda: vloga zasipa in začetnih statičnih pogojev

Cerović, Lazar (author), Maček, Matej (mentor), Zimmaro, Paolo (comentor)

Magistrska naloga raziskuje izzive napovedovanja stopnje poškodbe cevovoda pri potresnih razmerah. Pri tem se izkazuje, da so ocene, ki temeljijo izključno na najvišjih hitrostih tal, materialu cevi in velikosti cevi, neustrezne. Z analizo faktorjev varnosti pri različnih materialih, premerih in pogojih vgradnje cevi naloga dokazuje, da robni pogoji, kot so postavitev, globina cevi in lastnosti jarka cevi, pomembno vplivajo na statično varnost cevovodov in posledično na njihovo potresno ranljivost. Naloga se osredotoča na prehodne deformacije in analizira prečne zlome cevi pod različnimi pritiski, da bi boljše razumeli njihov odziv na okoljske pogoje in obremenitve. Za vsak material cevi je bilo izvedenih med 75.000 in 135.000 izračunov faktorjev varnosti na podlagi različnih začetnih statičnih pogojev. Čeprav verjetnost zloma cevi ni bila izračunana, je izračunan faktor varnosti različnih materialov in velikosti cevi, prikazan pri različnih pogojih vgradnje cevi. Naše ugotovitve kažejo, da bi morali modeli ranljivosti cevi na potresne razmere vključevati začetne statične pogoje, saj cevovodi pred potresnimi dogodki nikoli niso v stanju "ničelne obremenitve". Poleg tega se varnostni faktorji zelo razlikujejo glede na lokacijo in posebnosti postavitve cevi, zato zanašanje na en sam standard ne zajame vseh seizmičnih tveganj v različnih krajih po svetu. Naloga poudarja potrebo po podrobnih ocenah lokacije cevi, da se zagotovi bolj odporna cevovodna infrastruktura.

• Language: Slovenian
• Keywords: posteljica, obsip, varnostni faktor, PGV, stopnja popravil
• Work type: Master's thesis/paper
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Year: 2024
• PID: 20.500.12556/RUL-166225
• Publication date in RUL: 25.12.2024

CEROVIĆ, Lazar, 2024, Ocena negotovosti pri potresno povzročeni poškodbi cevovoda: vloga zasipa in začetnih statičnih pogojev [online]. Master’s thesis. [Accessed 14 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=166225

Secondary language

• Language: English
• Title: Assessing Uncertainty in Seismic-Induced Pipeline Damage: The Role of Bedding and Inital Static Conditions

Abstract

This thesis explores the challenges of predicting pipeline repair rates in earthquake conditions, showing that estimates based solely on peak ground velocity, material, and pipe size are inadequate. By examining factors of safety across various materials, diameters, and installation conditions, the study demonstrates that boundary conditions such as embedment, pipe depth, and trench properties significantly impact the static safety of pipelines and, consequently, their seismic vulnerability. Focusing on transient deformations, this research analyses cross-sectional breakage of pipes under different pressures to understand their response to environmental conditions and loads. For each pipe material, between 75,000 and 135,000 cases were calculated to evaluate factors of safety based on varying initial static conditions. Although the probability of breakage was not calculated, performance across materials and sizes was demonstrated under different pipe installation conditions. Findings suggest that pipe fragility models should incorporate these pre-existing conditions, as pipelines are never at a “zero-load” state before seismic events. Additionally, as safety factors vary widely based on site and installation specifics, relying on a single design standard does not capture all seismic risks in different locations around the world. This study underscores the need for detailed site assessments to ensure more resilient pipeline infrastructure.

• Keywords: bedding, factor of safety, PGV, repair rate