The idea of seismic monetary loss has gained significant attention as a practical measure for gauging the building performance. However, the process of assessing seismic loss is inherently complex and time consuming. In this dissertation, a probabilistic displacement based seismic loss assessment procedure is developed as a simplified tool to facilitate this process in four steps.

Firstly, simplified probabilistic displacement based assessment is generated for single degree of freedom systems as an extension to displacement based assessment initially proposed by Priestley et al. (2007). For that purpose, linear regression analysis in log space is conducted and new intensity-ductility relationships are proposed. The newly proposed relationships are trialled for two case study structures; an RC bridge and an eccentrically-braced steel frame parking structure. The intensities associated with exceeding three different limit states are found through the newly developed intensity-displacement relationships and are compared against those found through multi-stripe analyses. It is seen that the new relationships can predict the corresponding intensities with acceptable accuracy.

Secondly, systems with double perfectly correlated failure mechanisms are investigated, and a closed-form solution is provided to compute the associated annual probability of system failure. Typically, practitioners choose the smallest median intensity when considering several possible failure mechanisms, regardless of the uncertainty in the mechanisms’ capacity. The newly developed solution to assess multiple mechanisms is applied to a bridge with two possible mechanisms. It is illustrated that although the second mechanism has larger median capacity, accounting for its contribution in the bridge’s annual probability of failure increases the failure chance by 50% in comparison with the case of assessing system failure accounting for the only first mechanism.

Thirdly, a framework is developed to extend the probabilistic displacement based assessment procedure proposed for SDOF systems in the second chapter to be applicable for multi-storey R.C wall buildings. This framework is illustrated for a 4-, 8-, and 12-storey RC wall buildings as three case studies. The intensities associated with exceeding three limit states identified through direct displacement based assessment are compared with those obtained through multi-stripe analyses. The comparison demonstrates that the direct displacement based assessment approach can approximate the limit state exceedance’s intensity with practical accuracy. Furthermore, the annual probability of limit state exceedance is calculated by employing the approximated intensity and the improved SAC/FEMA approach.

Fourthly, modifications to bilinear limit state loss-intensity model proposed by Sullivan (2016) are suggested, and a new trilinear loss model is developed. The modified bilinear loss model and newly proposed trilinear loss model are applied to estimate the expected annual loss (EAL) for 4- and 12- storey buildings located in Wellington and a 4-storey building located in Christchurch, possessing eccentrically braced steel frame structures. The estimated EAL is compared with that found through rigorous loss assessment (outlined by FEMA P-58), and the proposed damage state loss- intensity models are found to be practically accurate.