On 6 April 2021, a 200 m-long under-construction prestressed concrete bridge failed in the Chitwan District in central Nepal. Two of the four bridge spans collapsed without any notable evidence of dynamic force application. Under-construction bridge failures are sometimes reported and can have a significant impact on the future construction adjustments. Thus, a detailed study of failure mechanisms will be insightful for the structural engineering community. Aiming to document the failure modes and exemplify lessons for improvement, this paper reports the detailed component level failure mechanisms of the bridge using visual inspection, site measurements, finite element modeling, and some forms of non-destructive testing. The chronological failure mechanisms are presented based on the field evidence and juxtaposed with the results of analytical modeling. The sum of findings highlights that the dead load failure, triggered by the settlement of falseworks, is the most critically governing factor that initiated and aggravated the damage scenario.

No abstract

Bal Mandir is a Palladian style three-storied monument located in Kathmandu, Nepal. The monument was damaged by the 2015 Gorkha earthquake and part of the aggregate building was declared inoperable after post-earthquake damage assessment. Bal Mandir serves an orphanage and educational center for the orphans and homeless children; seismic performance of the monument is a crucial concern. Aiming to quantify the damage level of the aggregate masonry building, field reconnaissance was performed in preliminary to detailed level. Furthermore, ambient vibration tests were carried out to perform system identification of the building. The results of system identification were compared with that of finite element analysis and the results show that damage has caused detectable change in the dynamic properties of the structure. This paper reports some representative damage scenarios and the results of the finite element analysis as well system identification.