Though the developer of the Burj Dubai continues to keep the ultimate height of the 800-meter-plus-tall super-skyscraper a secret, the tower keeps stretching up. Workers have finished the steel-framed spire that tops its concrete frame. One of the tower’s cranes has been dismantled, and the delayed cladding installation has been playing catch-up using an “up-up” method. Workers have built the steel pinnacle within the spire and will soon jack it into place, more than two months later than expected. A source close to the project implies the lift is imminent, but the secretive Emaar Properties is not releasing the date. Samsung Corp., Seoul, is building the tower, designed by the Chicago office of Skidmore, Owings &Merrill.