This can be translated in active form. Possible meanings are 1) the people tore the houses down to make walls to defend against the Chaldeans. Alternate translation: "that the people have torn down to defend against the siege ramps and the sword" or 2) Alternate translation: "the houses that the Chaldeans have torn down to make siege ramps so they can make war" (See: [[rc://en/ta/man/translate/figs-activepassive]])