The lack of any crater damage would argue against a truck bomb, and an explosion above would mostly dissipate upwards.
An explosion below would produce heave lifting adjacent spans and breaking their connections to be piers. As Nutty points out the low location is perfect to maximum any heave.
Argument against planted charges is both the CCTV coverage and reported extensive sea and other surveillance. Getting onto the structure and wiring that amount of explosives in place wouldn’t be inconspicuous.
Last edited by ORAC; 8th Oct 2022 at 08:42.