Chapter 4: Bridge Plan Review Processes

Section 1: Preliminary Bridge Layout Review

Overview

Preliminary bridge layout review (PBLR) and approval is required for
all bridges
with federal funding
, regardless of funding
category
,
and for all bridges crossing TxDOT right of way
 before any detail work is performed.
A Hydraulics & Hydrology (H&H) Drainage Analysis Report must be submitted with each PBLR. If the bridge crosses a waterway, the H&H Drainage Analysis Report must include the required scour evaluation
.
The review typically takes two weeks from the date of submittal but
may depend on the complexity and the number of bridges in the submittal
.
The layout is reviewed by the following:
  • Design Division
    • Hydraulics Section
    • Project Development Support Section
  • Bridge Division
    • Bridge Design Section
    • Bridge Management Section
    • Field Operations Section - Construction and Maintenance Branch
    • Field Operations Section – Geotechnical Branch
  • Others including Federal Highway Administration (FHWA), railroad, if required
  • The Bridge Management Section will keep a record
    of all
    layout
    s
    that are
     submitted, should further questions arise during plan development.
    The layout will be approved when all comments are addressed.
  • The Federal Highway Administration (FHWA) requires review and approval of the preliminary bridge layout when they have oversight.
  • If a railroad is involved, the layout (Railroad Exhibit A of the railroad agreement) is sent to the railroad company for their review and approval.
District should refer to the PBLR and PS&E Review Standard Operating Procedures for information on: requirements, level of review, estimations of review time, and bridge cost estimation.
If the bridge is programmed for Category 6 funding, verify that it is eligible for one of the
three
funding programs listed in Chapter 2 of this manual.
Refer to the
Bridge Detailing Guide
for Preliminary Bridge Layout criteria, Completed Bridge Layout criteria, and typical layouts. Complete and submit the Information Sheet for Structural Design (Form 2252) with all preliminary layouts for projects to be designed by the Bridge Division.
The preliminary bridge layout submittal process is as follows:
  • The
    District Bridge Engineer
    must approve preliminary layouts prior to submission
  • The layout is submitted to the Bridge Division’s PS&E Review Branch for approval.
  • Email the submittal of PBLR folder link in ProjectWise to
  • E
    mail Subject: PBLR, CSJ, County
  • The layout is approved when Division review comments are resolved.
  • Begin work on bridge detail sheets only after receiving final approval of the bridge layouts from the Bridge Division.

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.

Bridge Division Submission Requirements

Submit all structures to be let under a single project as one submittal to ensure uniformity of design and eliminate duplication of standards. Submittal requirements for typical bridge layouts and those involving a railroad are listed below.
The transmittal e-mail from the
District
 to the Bridge Division’s PS&E Review Branch must contain the following information:
  • District
     (both letting
    District
     and designing
    District
    , if different)
  • County
  • CSJ
  • Facility
    carried
    and feature crossed
  • Ready-to-let date and proposed letting date
  • Project type (new construction, rehabilitation, replacement, widening, etc.)
  • Bridge designer (
    District
    , division, consultant)
  • Point-of-contact information
  • Request for review
  • Any relevant information that the division may need to complete its review
  • Preliminary bridge layout
  • Typical sections sheet
  • Construction sequence sheet
  • Drainage Area Map and Hydraulic Sheet
  • H&H Drainage Analysis Report
    and HEC RAS models for more complex hydraulic models
  • The H&H Drainage Analysis Report, Drainage Area Map, Hydraulic Data Sheet, and Bridge Scour Data Sheet
     for all span bridges over a stream crossing.
  • Plan and profile sheets showing the project limits and the completed original of Form 1002 (p. 3 of 3) for all projects funded by Category 6.
  • A map view of the project illustrating the relationship of the roadways if the project is an interchange, or an
    interchange
     exists within the vicinity
  • The Railroad Exhibit A plan sheets, if applicable. Exhibit A must also be submitted to the Rail Division’s Rail Safety Section.

Federal Compliance Submission Requirements

The Federal Highway Administration (FHWA) requires TxDOT to submit preliminary structural layouts to FHWA for review and approval as follows.
The Bridge Division submits to the FHWA Texas Division for approval
of
all preliminary structural layouts for all bridges, major geotechnical features
,
 and major hydraulic structures on projects for which FHWA has retained oversight. A list of these projects is available from the Design Division.
For all other projects, the FHWA Texas Division and the FHWA Headquarters Office of Bridge Technology approve preliminary documents for unusual bridges and structures, including the following:
  • Difficult or unique foundations
  • New or complex designs with unique operational or design features
  • Bridges with span lengths greater than 600 ft.
  • Cable-stayed or suspension bridges
  • Bridge types that deviate from AASHTO specifications
  • All vehicular tunnels
  • Bridges with major supporting elements of ultra-high strength materials
  • Geotechnical structures featuring new or complex wall systems or ground improvement systems
  • Hydraulic structures involving complex stream stability measures
  • Designs or design techniques that are atypical or unique
Include the following items in the preliminary documents for unusual bridges and structures submitted by TxDOT to FHWA:
  • Description of structure-related environmental concerns and suggested mitigation
  • Studies of bridge types and span arrangements
  • Approach span-bridge layout plans and profile sheets
  • Controlling vertical and horizontal clearance requirements
  • Roadway geometry
  • Design specifications used
  • Special design criteria
  • Special provisions
  • Cost estimates
  • Hydraulic and scour design studies and reports showing scour prediction and related mitigation
  • Geotechnical studies and reports and information on substructure and foundation types

Railroad Exhibit A Submission Requirements

If a railroad is involved, Railroad Exhibit A is sent to the railroad company for preliminary review and approval of the bridge project. Railroad Exhibit A is included in the agreement that must be negotiated between TxDOT and the railroad company. The Rail Division’s Rail Safety Section (RRD-RSS) is the sole point of contact and Office of Primary Responsibility for all matters relating to agreements with the railroad companies. They are responsible for the submittal of all Exhibits needed in the execution of the various types of railroad agreements, including Exhibit A drawings for structures. The
District
 office submits Railroad Exhibit A drawings to the RRD-RSS at least 1
8
 months prior to the scheduled contract letting date to allow adequate time for negotiations and processing with the railroad company.
Requirements for the preparation of Railroad Exhibit A, as well as the policy and practices concerning highway-railroad grade separation structures, can be found in the
Rail-Highway Operations
Manual.