Chapter 2: Layouts and Estimated Quantities

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Section 1: General Information

Bridge Layouts

Bridge layouts are a pictorial representation of what the bridge looks like. Bridge layouts should be drawn accurately and commensurate with the clarity of presentation. For example, the bridge slab depth may need to be exaggerated in the elevation view.

The Bridge Layout Sheet shall contain, but is not limited to, the following listed details:

Plan View - normally shown in ascending stations from left to right
Elevation View - normally shown as a section through the profile grade line or control line and should be visually aligned with the plan view
Typical Transverse Section - showing only the superstructure. Not required when Staged or Phased Construction Sheet is included.

The Bridge Layout Sheet shall be detailed using one of the following listed scales for both horizontal and vertical:

1" = 20'
1" = 10'
NOTE: Do not mix horizontal scales and vertical scales.

These scales are for full-size English sheets (22" x 34"). For plotting in half-size English sheets (11" x 17"), the scales translate to 1" = 40' and 1" = 20', respectively.

Dimensioning tolerances shall normally be shown on the Bridge Layout Sheet as listed below:

Structural dimensions - bridge and rail lengths on plan view in decimal feet to the neartest 0.01'. Widths on plan and transverse section views in feet and inches to the nearest 1/4" (all decimals are acceptable, and preferred, on complex structures).
Piling or Drilled Shafts - in feet rounded up to the next whole foot for lengths and in inches for the pile and drill shaft size
Columns - in feet rounded up to the next whole foot
Elevations - in decimal feet to the nearest 0.001'
Bearings and Angles - in degrees, minutes, seconds to the nearest whole second if such accuracy is available
Stations - in decimal feet to the nearest 0.01'

The most accurate representations on a bridge layout are the profile grade line (or control line) in the plan view and the ground line on the elevation view. The ground line at the column locations may be scaled from the layout elevation view grid pattern. This elevation may then be used, along with the calculated bearing seat elevations, calculated cap depths, desired depth of foundations below ground, etc., to determine the column heights. The column heights should not be measured directly off of the layout.

All computer-aided drawing (CAD) files for TxDOT jobs must be created with MicroStation and utlilizing TxDOT’s customized font library or font resource file, furnished by the Bridge Division. Only Font 1 should be used for generating text in a set of plans.