Applied Knowledge

Infrastructure Vulnerabilities to Explosions and Natural Disasters

October 13th, 2022 · 12:33 pm @   - 
Date of Occurrence: October 8, 2022 Location: Crimea Event: Explosion Fatalities: Unknown Injuries/Displaced: Unknown

On Saturday October 8, 2022, news broke of an explosion on the Kerch Bridge in Crimea that caused severe damage to one of the structural bays of the bridge, and ignited a severe fire on an adjacent rail bridge that had a train transporting fuel. This devastating attack showed key vulnerabilities for critical infrastructure that could have been mitigated during the design phase with a detailed threat and vulnerability assessment taking into account potential threats and adjacencies

Bridges are generally very robust structures designed for heavy gravity loads caused by moving vehicular traffic and are optimized for the travel direction of the heavy loads. These design requirements result with the bridge deck generally being supported on the large vertical piers, relying on the heavy self-weight of the bridge to provide stability. In these situations, uplift is not the governing load direction, and the connection design therefore focuses much more on the gravity loads. However, in seismic areas, these connections may be upgraded to support severe lateral and uplift load. This creates a potential vulnerability such that, under severe load condition such as explosions, the bride deck could fail under load reversal caused by direct uplift loads or rebound caused by the dynamic vibration of the bridge.

Another vulnerability that could have been prevented during the assessment and design phase is associated with adjacencies of critical systems. It is very common to utilize bridges and other infrastructure to transport critical utilities (gas pipes, electrical/communication systems, etc.) without paying attention to the effects that the failure of the bridge can cause on these systems and the areas affected. Also, the adjacency between the vehicle bridge and the railroad bridge, which was likely considered to optimize cost, can result in propagation of damage with a secondary fire in the rail bridge.

This example, and other examples like the collapse two bridges within a matter of weeks in the amazon that caused the isolated of a large community, show that infrastructure planning is missing key design studies like threat and vulnerability assessment before and after construction as well as disaster recovery plans that can help mitigate the disruption effects.