Vertical irregularity is one of the major causes of the failure of the structure. Buildings with vertical irregularities are widespread and unavoidable during rapid urbanization in almost all countries. The safety of such buildings is most important against vulnerability in an earthquake. The vulnerability of structures is assessed using the damage indices of fragility curves. These fragility curves were developed using the HAZUS method, which is used to find the probability of structural damage due to various seismic excitations. This fragility curve determines the probability of none, slight, moderate, extensive, and complete damage to the structures. These fragility curves help to identify the vulnerability percentage of vertical irregularities compared to the regular building. Research also reveals that the vulnerability of the irregular building is similar to the vulnerability identified in terms of roof displacement, base shear, and drift ratio using the THA method. This research also helps to determine the possibility of damage being observed for the structures carrying stiffness and mass irregularities. It is found that stiffness irregularity is more vulnerable than mass irregularity. An increment in collapse probability is observed in stiffness and mass irregularity on the ground floor. Considerable slight to moderate damage possibility is observed in mass irregularity models, and collapse possibility is observed high in stiffness irregularity models. Also, it is observed that the SSI affects adversely on the structures.

The subterranean environment of tunnels poses considerable uncertainty as tunnel structures are ensconced in soil, unlike their above-ground counterparts. This significantly complicates tunnel risk assessment during earthquakes. This study introduces a novel method that integrates multiple damage indices to evaluate the seismic resilience of tunnels. Initially, seismic attenuation is introduced to calculate earthquake exceedance probabilities for various tunnel damage indicators, employing finite element methods (FEM). A robustness evaluation criterion scale value is established based on the amalgamation of multiple tunnel damage indices. Standard Cloud Models are then generated utilising the robustness evaluation criteria. Subsequently, the independent and correlated weights of the robustness evaluation indices are determined using the CRITIC-G1 and decision-making trial and evaluation laboratory (DEMATEL) methods, respectively. A game theory (GT) method is then utilised to amalgamate and allocate weights to these robustness evaluation indices. The evaluation Cloud Models are subsequently generated using a backward cloud generator, based on the division of damage grades for the evaluation criteria and combination weights. Finally, the robustness grade is determined by comparing the similarities between the standard and evaluation Cloud Models. The repair time of the tunnel is quantified using a repair function based on robustness grades. The efficacy of the seismic resilience assessment method is discussed based on three hypothetical cases, providing valuable guidance for assessing the seismic resilience of underground structures.

In the present study, four different SPT-based methods for liquefaction assessment namely Seed and Idriss (S-I), Tokimatsu and Yoshimi (T-Y), Japan Road Association (JRA), and Chinese code for Seismic Design of Buildings (CSDB) method has been discussed in detail. The present study compares the liquefaction potential estimation of S-I, T-Y, and JRA methods, respectively. The S-I method predicts 9.29 and 3.42 times higher liquefaction occurrence compared to JRA and T-Y methods respectively. Different damage indices such as liquefaction potential index (LPI), liquefaction risk index (LRI), and ground settlement have been evaluated for an earthquake magnitude of 7.5 on the Richter scale and peak ground accelerations varying in the range of 0.1-0.36 g respectively. LRI provides a more precise estimation of the liquefaction damages compared to LPI. The gradation of liquefiable soil has been presented and compared with the established limits of liquefiable soils.