I think the major ports (APM, Norfolk, Navy, and the shipyards) are all accessible over tunnels rather than under bridges. For sure, if the Jordan, High Rise, Berkeley bridges, and/or a handful of railroad bridges went down, that would cause problems for some businesses. Take a look at the satellite image of Norfolk/Portsmouth/Hampton. You can see most of the stuff is on the “right side”of any bridges.
Now, how a tunnel collapse would affect the area is a murkier question. Technically, ships could presumably still cross, but I’m sure there would be some kind of disruption. Probably shorter than the time needed to remove a collapsed bridge.
TL;DR: there would be an impact, but I don’t think any bridge serves as a “gateway” to the ports or shipyards.
That’s correct. Hampton Roads is a major military area, particularly for the Navy and because of that when the water crossings were built, they wanted to use tunnels specifically because they didn’t want the harbor to be blocked during a war. The original version of the Hampton Roads Bridge Tunnel (HRBT), opened in the 1950s, so World War 2 was likely still pretty fresh in people’s minds.