Document Type : Original Article

Authors

• Jalal Akbari ¹
• Hamid Mehraznia ²
• Mostafa Fathisepahvand ³
• Vahid Lachinov ⁴

¹ Associate Professor Department of Civil Engineering, Bu-Ali Sina University, Hamedan, Iran.

² Master of Science in Civil Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran.

³ Assistant Professor, Department of Structural Engineering, Chulalongkorn University, Bangkok, Thailand.

⁴ Master of Science in Structural Engineering, Consulting Engineer, Hamadan, Iran.

Abstract

Objective: The present study evaluates the seismic vulnerability of two buried reinforced-concrete reservoirs—Seyyed al-Shohada and Farmandari—located in Nahavand County in Hamedan. These reservoirs, each with a nominal capacity of 5,000 m³, constitute critical water-supply infrastructure for the region. The assessment was conducted using three-dimensional modeling in SAP2000, incorporating soil–structure and fluid–structure interaction effects. The analyses comprised linear static analysis and modal analysis under gravity and seismic loads, with seismic loading applied for two hazard levels—475-year and 2475-year return periods—in accordance with Standard 2800 and Publication No. 360. The results indicate that elastic stresses in the reservoir walls, roof slab, and base slab remain below the concrete compressive strength across all load combinations, and the demand-to-capacity ratios for most primary structural members fall within acceptable limits. The fundamental period was computed to be approximately 0.385 s, supporting the use of the maximum acceleration response spectrum. Nevertheless, reinforcement corrosion in the underside of the roof slab and the reduction of concrete cover represent serious concerns. Periodic monitoring of the reservoirs for cracking, reinforcement corrosion, and diminishing concrete cover is therefore deemed necessary. Overall, the reservoirs under study currently exhibit an acceptable level of seismic resistance; however, given their long service life and observed signs of deterioration, the implementation of preventive measures is recommended to ensure their long-term performance.

Keywords

• Seismic vulnerability
• Concrete reservoirs
• Semi-buried reservoirs
• Reinforced Concrete
• Demand-capacity ratio

Main Subjects

• Earthquake