Condition index of reinforced concrete bridges in Karachi by using rapid visual screening and fragility functions

Bridges act as connections in a city’s transportation system to meet the rising demand for travel, achieve the greatest feasible land use and promote economic interests. In order to prevent serious damage during their service and any natural calamities, especially in poor nations, their periodic quantitative or qualitative assessment is essential to preserve the structure’s performance. Therefore, the current study’s objective is to create a logical rapid visual screening (RVS) system and apply it globally to the existing bridges in Karachi, Pakistan’s largest metropolis, as part of the creation of a mass transit scheme. This study only uses bridges that are situated on main thoroughfares, and on the red and yellow bus rapid transit lines, as case studies in order to ensure the successful implementation of the recommended methodology. Furthermore, using the innovative bridge RVS application, the maintenance urgency index has been calculated by tracking the defective sites based on component importance, as well as the seismic vulnerability score estimated by employing the fragility functions. Based on the results, the identified bridges can be ranked according to the degree of maintenance rehabilitation and their susceptibility to seismic risk in order to help the authorities in repair and maintenance.