Numerical investigations on the residual capacity and economic losses of earthquake-damaged reinforced concrete wall structures

The substantial damage to Reinforced Concrete (RC) structural walls observed from post-earthquake reconnaissance has prompted the attention on the need for improved code-based design provisions for these structural elements as well as for detailed investigations on their residual capacity, typically neglected in the retrofit/repair evaluation. Although several research works and international guidelines focusing on the seismic performance of damaged structural walls are available from a state-of-the-art review, a specific methodology to evaluate the earthquake-related damage to structural walls is still missing in literature. Therefore, this research work investigates the seismic residual capacity of RC walls through parametric numerical analyses, aiming to provide indications on the assessment methodology to be used in practical applications. The numerical investigation is initially carried out by implementing Finite Element Modelling of RC walls with different mechanical properties and expected failure mechanisms. This allows to evaluate and collect stiffness/strength reduction coefficients to be adopted for different post-earthquake damage conditions. Then, the influence of residual capacity on the economic seismic losses of wall structures is investigated and discussed. Specifically, a multi-story case-study RC building is selected, and pre- and post-earthquake loss assessments are carried out considering alternative wall typologies and damage levels. Analytical-based nonlinear analyses highlight that the loss of stiffness and strength can lead to increasingly higher economic losses depending on the damage level of the structural wall. Moreover, substantial economic losses can be estimated if residual capacity is taken into account even at low-intensity seismic levels. Therefore, such methodology could provide valuable information to support decisions on the post-earthquake repair/retrofit/demolition.