Earthquakes and Structures

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Seismic strengthening of a reinforced concrete building using the SLaMA methodology

  • Cagri Cetik (Department of Civil Engineering, Dokuz Eylul University, Central Campus) ;
  • Sadik C. Girgin (Department of Civil Engineering, Dokuz Eylul University, Central Campus)
  • Received : 2025.01.27
  • Accepted : 2025.07.16
  • Published : 2025.10.25
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Abstract

Numerous earthquakes worldwide cause significant loss of life and property, emphasizing the urgent need for earthquake-resistant structures. Many buildings in Türkiye built before the 2000s fail to meet modern seismic codes, posing serious risks. Strengthening or rebuilding high-risk structures is essential; however, detailed nonlinear analysis for all buildings is impractical due to time and cost. Rapid assessment methods help prioritize buildings needing detailed evaluation. This study investigates the seismic performance of an existing reinforced concrete building using the Simplified Lateral Mechanism Analysis (SLaMA) method, recommended by the New Zealand Society for Earthquake Engineering (NZSEE). Beam-column joint damage was assessed using the strength hierarchy approach. Strengthening alternative concrete jacketing and carbon fiber reinforced polymer (CFRP) plates-were evaluated through hand calculations, SeismoBuild, and FRP Designer software. Plastic hinge lengths were validated using experimental data. Seismic performance was also assessed in accordance with the Turkish Building Earthquake Code (TBEC 2018), based on plastic rotation demands and capacity comparisons. Concrete jacketing alone improved base shear by 2.4 times and increased the %NBS score from 39% to 54% in the X-direction but was insufficient to meet performance targets. With additional CFRP beam strengthening, the %NBS score exceeded 68%, satisfying NZSEE thresholds. According to TBEC (2018), the structure's performance level improved from "collapse prevention" to "controlled damage" only after both columns and beams were retrofitted. The SLaMA method effectively identified structural weaknesses and prioritized retrofit needs, while TBEC provided a rigorous framework for validating seismic performance improvements.

Keywords

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