Authorities say the bridge over the River Jacui gave way Tuesday in the state of Rio Grande do Sul.
Heavy rains have battered Brazil's southeastern region, where mudslides have killed at least 80 people. In Rio Grande do Sul, flooding has forced more than 1,000 people from their homes.
Brazil's coastal region has steep hillsides that gave way in many areas after days of rain.
Authorities say more rain forecast for the coming days could cause more mudslides.