Consideration of aging and SSI effects on seismic vulnerability assessment of RC buildings

• Published in: Bulletin of earthquake engineering Vol. 12; no. 4; pp. 1755 - 1776
• Main Authors: Pitilakis, K. D., Karapetrou, S. T., Fotopoulou, S. D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2014; Springer; Springer Nature B.V
• Subjects: Aging; Applied sciences; Assessments; Building failures (cracks, physical changes, etc.); Building structure; Buildings; Buildings. Public works; Civil Engineering; Construction (buildings and works); Corrosion; Corrosion rate; Durability. Pathology. Repairing. Maintenance; Earth and Environmental Science; Earth Sciences; Environmental Engineering/Biotechnology; Exact sciences and technology; Fragility; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Geotechnics; Hydrogeology; Original Research Paper; Reinforced concrete; Reinforced concrete structure; Reinforcing steels; Seismic activity; Seismic engineering; Seismic hazard; Seismic surveys; Stresses. Safety; Structural analysis. Stresses; Structural behavior; Structural engineering; Structural Geology; Structure-soil interaction; RC buildings; SSI; Seismic vulnerability; Time-dependent fragility curves; Aging effects; IDA; Dynamic characteristic; Earthquake effect; Aging test; Vulnerability; Modeling; Reinforced concrete; Time dependence; Corrosion; Deterioration; Failure analysis; Concrete construction; Numerical simulation; Structure soil interaction; Structural analysis
• ISSN: 1570-761X; 1573-1456
• DOI: 10.1007/s10518-013-9575-8

At present, the seismic vulnerability assessment of reinforced concrete (RC) buildings is made considering fixed base conditions; moreover, the mechanical properties of the building remain intact in time. In this study we investigate whether these two fundamental hypotheses are sound as aging and soil-structure interaction (SSI) effects might play a crucial role in the seismic fragility analysis of RC structures. Among the various aging processes, we consider the chloride-induced corrosion based on probabilistic modeling of corrosion initiation time and corrosion rate. Different corrosion aspects are considered in the analysis including the loss of reinforcement cross-sectional area, the degradation of concrete cover and the reduction of steel ultimate deformation. SSI is modeled by applying the direct one-step approach, which accounts simultaneously for inertial and kinematic interactions. Two-dimensional incremental dynamic analysis is performed to assess the seismic performance of the initial uncorroded ( t = 0 years) and corroded ( t = 50 years) RC moment resisting frame structures, having been designed with different seismic code levels. The time-dependent fragility functions are derived in terms of the spectral acceleration at the fundamental mode of the structure S a ( T 1 , 5 %) and the outcropping peak ground acceleration for the immediate occupancy and collapse prevention limit states. Results show an overall increase in seismic vulnerability over time due to corrosion highlighting the important influence of deterioration due to aging effects on the structural behavior. Moreover, the consideration of SSI and site effects may significantly alter the expected structural performance leading to higher vulnerability values.