Engineering Assessment of Structural Deterioration and Preservation Challenges in a Corroded Reinforced Concrete Building Exposed to a Marine Environment

The preservation of twentieth-century reinforced concrete buildings increasingly requires the integration of structural engineering assessment with heritage conservation principles. Although the deterioration mechanisms of reinforced concrete in marine environments have been extensively investigated, relatively few studies have examined how advanced material degradation affects the technical feasibility of preserving modern reinforced concrete heritage structures. This study addresses this gap through the structural assessment of the Patras Port Authority Building (OLPA), a reinforced concrete building constructed in the early 1970s and exposed for more than five decades to an aggressive coastal environment, providing the engineering basis for determining whether a complete code-based structural assessment is justified in accordance with KAN.EPE. and EN ISO 13822. A comprehensive inspection and testing program was carried out, including visual inspection, crack mapping, concrete core testing, carbonation-depth measurements, pH determination, chloride-content analysis, half-cell potential measurements, electrical resistivity measurements, and selective exposure of reinforcement. The engineering assessment revealed extensive deterioration of the structural system, including low concrete strength (approximately C8/10), carbonation exceeding the concrete cover, pH values between 7 and 8, chloride concentrations ranging from 0.0377% to 0.8975% by cement mass, and severe reinforcement corrosion. The measured average cross-sectional loss reached 34.5% for longitudinal reinforcement and 65.6% for transverse reinforcement (stirrups), accompanied by significant reductions in mechanical properties and ductility. It should be noted that concrete samples for chloride determination were collected at depths well beyond the reinforcement level. Additional deficiencies associated with inadequate confinement reinforcement, outdated seismic detailing, previous earthquake damage, cracking in columns and shear walls, and uncertainty regarding the geometry and condition of the foundation system further increase structural vulnerability. The engineering assessment indicates that the combined effects of long-term environmental exposure, corrosion-induced deterioration, obsolete design provisions, and existing structural deficiencies substantially reduce the reliability and seismic performance of the load-bearing system. Within this context, the study examines the implications of advanced deterioration for the preservation of reinforced concrete heritage buildings and proposes an integrated assessment framework that combines structural safety, durability, material integrity, intervention feasibility, and heritage significance. The proposed approach contributes to a more comprehensive engineering-based methodology for evaluating preservation strategies for aging reinforced concrete buildings exposed to aggressive marine environments. These findings also raise important concerns regarding the technical feasibility of preserving ageing reinforced concrete buildings located in highly seismic regions, where ensuring structural safety may require the introduction of new load-bearing elements together with the replacement of a substantial portion of the already deteriorated original material.