Seismic Assessment of Existing Precast Concrete Large-Panel Buildings in Albania: A Case Study

Precast reinforced concrete (RC) large-panel buildings (LPBs) are a common residential construction typology in urban areas of Eastern European countries, including Albania. Due to the ageing of these buildings, which date back to the 1970s, and the country’s high seismic hazard, it is very important to assess their seismic safety. This study presents a code-based seismic assessment of a five-storey case-study building in Tirana, Albania’s capital, for which limited information was available and was solely based on the original construction specifications (due to the absence of in situ material testing). A 3D finite-element numerical model was developed using LIRA-SAPR 2024 R2 (version 24.2.0.0) software, and seismic analyses were performed using both multi-modal (response spectra) analysis and the equivalent static analysis procedures according to the current Albanian seismic design code (KTP-N.2-89) and the Eurocode 8 framework (including EN 1998-1 and EN 1998-3). Two different seismic hazard levels were considered to assess the effect of a significantly higher seismic hazard level (compared to the original design) on the seismic safety of older existing LPBs. A demand-to-capacity (DCR) assessment revealed significant structural deficiencies, at both the individual wall-panel level and the wall-assembly level. The representative interior load-bearing wall panel has inadequate flexural and shear capacity, with a DCR of 5.13 for flexure due to a very low vertical reinforcement ratio. The assessment also indicates that the vertical panel joint (D4) is the most critical component of the investigated wall assembly, since its shear capacity is governed by the tensile failure of the steel plate that connects the adjacent wall panels, corresponding to a DCR value of 13.89, indicating very high seismic vulnerability. The seismic assessment of the investigated case-study building may be useful for informing future efforts related to seismic assessment and retrofitting of similar LPBs in Albania and Eastern European countries.