Arnold;
One more possibility. Since your scene appears to be in the Bronx (based on a nearby item whose name I will NOT say 
), how about a Bronx staple - a section of elevated highway??? There are downward slopes near each end which could be covered by some concrete abutments, and the roadway could run across the horizontal pipe. It you construct it as a one piece flat that is somehow attached to the pipe, it would be fairly easy to remove if needed.
