MADRID - Spanish construction firm ACS said it had won a $983 million contract to design and build the longest cable-stayed bridge in the United States, in Texas. ACS, which will carry out the work through two of its subsidiaries, Dragados and Flatiron, will also operate and maintain the bridge for 25 years, it said in a statement late on Friday. The bridge will replace an existing one in the harbour of Corpus Christi, Texas, which will be demolished. The new structure will be high enough to accommodate transatlantic ships trying to reach the harbour, ACS said. It will also include the longest bridge span, or stretch of unsupported road, in the United States, of 504 metres.