MdSHA Ridge Road Bridge over I-70 in Frederick County, MD The Ridge Road Bridge spans Interstate 70 at the top of Braddock Mountain in Frederick County, Maryland.  It is an artery between Braddock Heights to the south and Shookstown and Gambrill Park to the north and east.  As you approach the bridge from the valley below, you see why the Federal Highway Administration suggested an arch type bridge as a fitting monument to the unusual beauty of the site.  The Maryland State Highway Administration of the Maryland Department of Transportation agreed with the federal engineers and arranged for the design.  Consulting engineers for the project were Green Associates, Inc., Towson, Md. The arching span, which clears the multiple lanes of I-70, has no piers on either side of the road, thus eliminating a potential roadside hazard.   When preparing the site, foundation blasting was done with extra care so that the rock formation was minimally disturbed. The arch has a span of 250 feet and carries a 22-ft roadway, with two 5-foot shoulders.  The top portions of the bridge are as much as 80 feet above I-70.   Spandrel Columns were fabricated out of 14-inch structural sections.  The deck girders are 36-inh deep structural sections.  The 22-foot-wide roadway has a 9-inch concrete slab.  With C. William Hetzer, Inc. serving as  general contractor, Pittsburgh Des Moines Steel Company fabricated and erected the steel.  Bethlehem Steel supplied 502 tons of structural shapes and plates for the project.