Whenever Bruce transforms into the Hulk, his clothes are torn, but his pants remain mostly intact. Since the Hulk is much bulkier than Bruce, Bruce's pants are too small for his size and should be completely torn like the rest of his clothes.
The military has strict protocols pertaining to civilians, yet Rick Jones has free access to the base, is able to assist Banner in his experiments, and can be present during highly classified army events (example - he accompanied Banner in transporting the deactivation code for the Cyclops computer in The Cyclops Project.)