Layout Approval Information

In addition to the requirements shown in the Bridge Detailing Guide, the following information is necessary for layout approval.
Stream Crossings
  • Submit the scour analysis envelope and calculated scour depth with the preliminary bridge layout.
    Do not show the envelope on the bridge layout, as it should be a separate sheet.
  • Submit
    H&H Drainage Analysis Report, Drainage Area Map, Hydraulic Data Sheet, and Bridge Scour Data Sheet.
Bridge Widenings
– I
nclude the following in the layouts:
  • Existing bridge widths and lengths
  • Width of existing bridge to remain and width of widening shown on plan view and typical section
  • Existing foundations
    , channel profile of existing conditions,
     and extents of documented scour
  • Submit H&H, if adding substructure elements
  • Updated scour analysis
  • Appropriate thickness of asphalt level-up coarse shown on the transverse section, if applicable
If stage construction is required
and written justification has been accepted by Bridge Division
, refer to stage construction requirements below.
Phased
 Construction
Show stage construction geometry and sequence on the bridge layouts, including proposed lane widths and temporary rail locations for each stage. Include existing bridges and foundation locations on the layouts. Use additional sheets if necessary.
Railroad Overpasses/Underpasses
For railroad overpasses or underpasses, submit the preliminary bridge layout to the Bridge Division, and submit Railroad Exhibit A to the Rail Division’s Rail Safety Section (RRD-RSS). Exhibit A includes the preliminary bridge layout and additional plan sheets required to obtain railroad company approval. See “Railroad Exhibit A Submission Requirements” later in this chapter for additional information. The preliminary bridge layout should place emphasis on the following items:
  • Location of railroad tracks and right-of-way
  • Intersecting mileposts of railroad and stations of roadway center lines
  • Railroad milepost marker and Department of Transportation crossing identification number
  • Elevation at top of rail
  • Vertical and horizontal clearances from center line of track
  • Railroad track profile
  • Direction of increasing railroad milepost
  • Proper title block indicating Railroad Exhibit A
  • Indication if grade-separation structure eliminates a highway-railroad at-grade crossing with active warning signals
  • Location of crash walls, if required
  • The Railroad Requirements for Bridge Construction sheets
Interchanges and Complex or Unusual Projects
Provide accurate geometric information on the plan and profile for roadways beneath structures for complicated designs such as braided ramps or interchanges. This information is vital to structural design because the types of bents required, such as straddle, single column, offset columns, etc., depend on the geometry of underlying roadways.
Retaining Walls
Preliminary layouts for retaining walls are required when the maximum height exceeds 25 ft. Submit preliminary layouts for walls and slopes undergoing certain types of ground-stability improvement measures for review. Such measures include the following:
  • Removing and replacing more than 5 ft. of soil.
  • A requirement for earth reinforcements exceeding 70% of the wall height.
  • Use of dynamic compaction, wick drains, stone columns, geo
    -
    piers, surcharging, or other measures to improve ground below walls or embankments.
Include justification in the preliminary submission for ground improvement, including soil testing and analysis leading to the decision to use ground-improvement techniques, as well as analysis of the ground improvement itself.