Bridge deck paving machines are set on top of and travel forward along screed rails during concrete placement. Where and how workers set the screed rails determines the final deck profile. To meet typical deck grade tolerances of + or - 1 inch, contractors require knowledge and skill in screed-rail placement. They must also consider how the movement of a loaded screed rail affects form deflection and bridge girder movement. Learn how to set screed rails to meet deck grade tolerances with attention to: * Finished deck grade * Construction grade control * Placing screed rails * Choosing screed rails and chairs * Crown adjustment