In this study, the earthquake risk assessment of single -story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub -classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub -class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub -classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

We have proposed a methodology to assess the robustness of underground tunnels against potential failure. This involves developing vulnerability functions for various qualities of rock mass and static loading intensities. To account for these variations, we utilized a Monte Carlo Simulation (MCS) technique coupled with the finite difference code FLAC3D, to conduct two thousand seven hundred numerical simulations of a horseshoe tunnel located within a rock mass with different geological strength index system (GSIs) and subjected to different states of static loading. To quantify the severity of damage within the rock mass, we selected one stress-based (brittle shear ratio (BSR)) and one strain-based failure criterion (plastic damage index (PDI)). Based on these criteria, we then developed fragility curves. Additionally, we used mathematical approximation techniques to produce vulnerability functions that relate the probabilities of various damage states to loading intensities for different quality classes of blocky rock mass. The results indicated that the fragility curves we obtained could accurately depict the evolution of the inner and outer shell damage around the tunnel. Therefore, we have provided engineers with a tool that can predict levels of damages associated with different failure mechanisms based on variations in rock mass quality and in situ stress state. Our method is a numerically developed, multi-variate approach that can aid engineers in making informed decisions about the robustness of underground tunnels. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).