This steel frame Trestle is being built beside an existing bridge that is being removed and replaced. The Trestle will be the work platform for the Crawler Crane and also Concrete Trucks when they build the new span. The method is to use a 12″ x 48″ x 30′ mat then put a single timber 12″ x 12″ x 36′. The extra length of the single timbers sticks out and provides the base for the sidewalk for the workers to have a safe egress.