It will cost taxpayers more than $40 million to repair the aged Bonner Bridge so it can be used without weight restrictions for the next 10 years. The 42-year-old bridge over Oregon Inlet is the only roadway to Hatteras Island. But portions of the nearly two-and-a-half-mile bridge are decaying, especially on its bottom side where concrete has chipped and steel structures are rusted and corroded. The state says an assessment calls for repairs to be made within the next four years to keep the bridge functioning for the next decade. State and federal officials are considering a replacement bridge, which likely would parallel the existing span and cost around $200 million.