Hunks of concrete fell out of the Interstate 20 bridge at Cooktown Road on the roadway below Friday forcing the state to close the bridge. The hole was discovered about midday and by 4 p.m. had grown to almost 3 feet square, large enough to see vehicles passing beneath the exposed rebar. State Department of Transportation and Development could not be reached late Friday afternoon for comment. The bridge, built in 1961, is maintained by the state. Ruston Public Works Director Darrell Caraway said Friday wasn’t the first time chunks had fallen out of the bridge.