FIELD APPLICATION FOR ASSESSING THE DAMAGE AND USABILITY OF BRIDGES AFTER AN EARTHQUAKE

After the last two major earthquakes that shook northwestern Croatia in 2020, field inspections of structures were carried out according to a previously defined methodology, which was implemented through a software application. However, this methodology and application was limited only to typical (multi)storey buildings made of masonry and/or reinforced concrete. A similar approach is now being developed specifically for bridges to create a standardized and straightforward procedure for post-earthquake inspection process. The results of the inspection are entered via a mobile application interface and then uploaded to a central cloud database. This data is divided into three categories: (1) general information about the bridge, its traffic and geometry, information about the structural system, superstructure and substructure definition, information about bearings, expansion joints and equipment; (2) results of the inspection with damage classification grades associated to each bridge element, ranging from mild, to moderate to severe, all according to the proposed methodology; and (3) final assessment of the bridge's usability. The usability of the bridge is assessed as usable, temporarily unusable or unusable according to the previously identified and classified damage. An unusable bridge is to be closed for traffic due to critical structural damage, while a temporarily unusable bridge can further be restricted to a defined traffic speed or vehicle weight, or further inspection or immediate construction work may be recommended to prevent further damage. The benefits of such a bridge usability classification are particularly important in post-earthquake aftermath when search and rescue operations are carried out, demolition crews and heavy machinery are deployed and mobile temporary housing units are transported. Furthermore, the central database with all the information collected can be used to manage and plan the rehabilitation and retrofitting of damaged bridges.