braces

items that connect two things together. "clamps" or "hinges"

more bronze than could be weighed

This is an exaggeration to show that there was a very large quantity of bronze. This can be stated in active form. AT: "so much bronze that no one could weigh it" (See: rc://en/ta/man/translate/figs-activepassive and rc://en/ta/man/translate/figs-hyperbole)