Seismic Fragility Analysis of 100 m3 Elevated Water Tanks in Türkiye: Assessment of Confinement Effect
10th Turkish Conference on Earthquake Engineering, TCEE 2025, İstanbul, Türkiye, 8 - 10 Ekim 2025, cilt.854 LNCE, ss.303-319, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 854 LNCE
- Doi Numarası: 10.1007/978-3-032-23614-2_18
- Basıldığı Şehir: İstanbul
- Basıldığı Ülke: Türkiye
- Sayfa Sayıları: ss.303-319
- Anahtar Kelimeler: Dynamic analysis, Elevated water tank, Fragility curves, Performance analysis, Structural fragility
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
The primary aim of this study is to assess the seismic performance and risk estimation of elevated water tanks with a capacity of 100 m3, which have been widely constructed across Türkiye. Although elevated water tanks were extensively used in the past, their construction frequency has significantly declined over time due to technological advancements. However, these structures—whether still in use or abandoned, particularly in agricultural and industrial facilities—pose substantial risks in the event of potential earthquakes because of reduced material strength and insufficient maintenance conditions. Given the risks they pose to life safety and economic activities in both residential and industrial areas, it is essential to conduct a comprehensive assessment of their structural condition and seismic performance, considering their current concrete strength levels and the limited structural capacity. In this study, the seismic behavior of an elevated water tank with low concrete strength (C10) and S220 reinforcement steel was analyzed under the condition of a fully filled reservoir. To investigate the influence of confinement on the structural capacity of elevated water tanks, two cases—confined and unconfined—were considered. A total of 30 different earthquake records were selected, consisting of 15 records within the 0.1 g–0.4 g range and 15 records within the 0.5 g–1 g range. The selected earthquake records were scaled based on Sa(g) at T = 1 s, and a total of 150 ground motion records were used for both principal directions at various intensity levels. Nonlinear time-history analyses were performed, and the results indicate that incorporating the confinement effect in reinforced concrete elements markedly enhances structural seismic behavior and lowers fragility by diminishing the probability of damage.