Numerical Study on Influence of Corrosion and Vertical Irregularities on Seismic Behaviour of RC Frame Structures

The structural vulnerability of RC structures during major seismic events raises several concerns regarding structural design and behaviour. Additionally, corrosion’s impact on steel and concrete, including a reduction in ductility, confinement and strength, can compromise structural performance, especially for reversal loading. This work investigates the combined effect of corrosion and seismic actions on the structural performance of RC structures. Numerical models of RC structures with 0%, 5%, 10%, 15% and 20% corrosion were proposed. The effect of corrosion in the numerical models was calibrated based on experimental studies carried out on corroded RC elements. Afterwards, we considered the scenario of corrosion in all peripheral structural elements of 5- and 10-storey MRF structures in three distinct conditions. To enforce vertical irregularity, we have imposed vertical irregularity at the ground level in each structure. An adaptive pushover analysis was performed to assess the effect of corrosion and vertical irregularity on the seismic response. The results demonstrate that, for the levels of 5% and 10% corrosion, uniform corrosion produces a deleterious impact on structural responses in 10- and 5-storey MRF structures, respectively, regardless of the level of irregularity of the elevation. However, the irregularity generates a higher impact in the seismic response than the uniformly distributed corrosion in height. The combined effect of those parameters must be considered in seismic codes for new and existing buildings in order to maintain safe performance levels.