Chapter 5: Bridge Plan Review ProcessesAnchor: #CACIEHFI
Section 1: Preliminary Bridge Layout ReviewAnchor: #i1043738
Preliminary bridge layout review (PBLR) and approval is required for all bridges, regardless of funding type, before any detail work is performed. The review typically takes two weeks from the date of submittal. The layout is reviewed by the following:
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- The Design Division’s Field Operations Section reviews the layout for roadway items, such as: Anchor: #FLEIRJVQ
- The Design Division’s Hydraulics Branch reviews the layout for hydraulic items, such as Anchor: #EGJAOELP
- The Bridge Division’s Geotechnical Branch reviews the layout for geotechnical items, such as Anchor: #JQNUIFKT
- The Bridge Division’s Design Section reviews the layout for structural items, such as Anchor: #VDOTVOSM
- A Bridge Division project manager keeps a record that the layout was submitted, should further questions arise during plan development. Anchor: #STRJTKMT
- The Federal Highway Administration (FHWA) requires review and approval of the preliminary bridge layout when they have oversight. Anchor: #JJEPPRUO
- 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.
If the bridge is programmed for Category 6 funding, verify that it is eligible for one of the four funding programs listed in Chapter 2 of this manual.
During the final Bridge Cost Information (BCI) review, the Bridge Division project managers verify that all design and funding issues identified during the preliminary bridge layout review have been resolved so that the project can proceed to letting. If the bridge is not eligible for the funding category or is not CONSTRUCT-authorized, the project cannot be let for construction. If there is a design problem requiring redesign of the bridge, the project may need to be pulled from the letting if there is not enough time to correct design issues. Avoid jeopardizing project letting dates by resolving all outstanding issues at the time of the preliminary layout review and not during the PS&E stage.
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 or their consultant pool.
The preliminary bridge layout submittal process is as follows:
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- The district bridge engineer must approve preliminary layouts prior to submission. Anchor: #DOJVXXPM
- The layout is submitted to the Bridge Division’s PS&E Review Branch for approval. Anchor: #CVTRGOCC
- 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.Anchor: #i1005493
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.
Bridge Widenings. For bridge widenings, include the following in the layouts:
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- Existing bridge widths and lengths Anchor: #LLCSLDRR
- Width of existing bridge to remain and width of widening shown on plan view and typical section Anchor: #ITVJFPOK
- Existing foundations and extents of scour Anchor: #EQFGJDWY
- Appropriate thickness of asphalt level-up coarse shown on the transverse section, if applicable
If stage construction is required, refer to stage construction requirements below.
Stage 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 Traffic Operations Division’s Rail Safety Section (TRF-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:
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- Location of railroad tracks and right-of-way Anchor: #GQFGCARD
- Intersecting mileposts of railroad and stations of roadway center lines Anchor: #XNATKFOQ
- Railroad milepost marker and Department of Transportation crossing identification number Anchor: #IFBGWPCI
- Elevation at top of rail Anchor: #DCPKWFCI
- Vertical and horizontal clearances from center line of track Anchor: #VHBDJXBE
- Railroad track profile Anchor: #TMAYJLPB
- Direction of increasing railroad milepost Anchor: #LTNONWLD
- Proper title block indicating Railroad Exhibit A Anchor: #KYPPPFAM
- Indication if grade-separation structure eliminates a highway-railroad at-grade crossing with active warning signals Anchor: #RUUORGCE
- Location of crashwalls, if required Anchor: #JFBYTLIF
- 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:
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- Removing and replacing more than 5 ft. of soil. Anchor: #KSYUYQSL
- A requirement for earth reinforcements exceeding 70% of the wall height. Anchor: #PROIXKJL
- Use of dynamic compaction, wick drains, stone columns, geopiers, 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.Anchor: #i1007310
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:
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- District (both letting district and designing district, if different) Anchor: #BNXQRLHT
- County Anchor: #RJBIFMWA
- CSJ Anchor: #PODLBGYI
- Facility and feature crossed Anchor: #YXPDRMBP
- Ready-to-let date and proposed letting date Anchor: #CTKPKUHE
- Project type (new construction, rehabilitation, replacement, widening, etc.) Anchor: #LMDAINGN
- Bridge designer (district, division, consultant) Anchor: #JOAIJVJH
- Point-of-contact information Anchor: #DSNISWGH
- Request for review Anchor: #UIVQDLRD
- Any relevant information that the division may need to complete its review Anchor: #TAQPGXYU
- Preliminary bridge layout Anchor: #HGBAWYRG
- Typical sections sheet Anchor: #SDQESEDH
- Construction sequence sheet Anchor: #AQEBGFHM
- Hydraulic plan sheets that include hydrology and hydraulics for simpler hydraulic models Anchor: #LLMJNMAB
- Hydraulic reports and HEC RAS models for more complex hydraulic models Anchor: #WQYQTQWR
- The hydraulic report and scour analysis for all span bridges over a stream crossing. Also include the total calculated scour depth. Anchor: #QLSTJINR
- 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. Anchor: #FJSVJIHJ
- 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 Anchor: #LYJPFHYP
- The Railroad Exhibit A plan sheets, if applicable. Exhibit A must also be submitted to the Traffic Operations 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 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:
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- Difficult or unique foundations Anchor: #WFKLTTGA
- New or complex designs with unique operational or design features Anchor: #PTMLNDOW
- Bridges with span lengths greater than 600 ft. Anchor: #CJUTXYQS
- Cable-stayed or suspension bridges Anchor: #BITQWPIC
- Bridge types that deviate from AASHTO specifications Anchor: #NDXHQDIN
- All vehicular tunnels Anchor: #DHDLLTGS
- Bridges with major supporting elements of ultra-high strength materials Anchor: #JABMJOVG
- Geotechnical structures featuring new or complex wall systems or ground improvement systems Anchor: #OYPIRDBC
- Hydraulic structures involving complex stream stability measures Anchor: #XJYHRCBP
- 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:
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- Description of structure-related environmental concerns and suggested mitigation Anchor: #DYCIOQHR
- Studies of bridge types and span arrangements Anchor: #OOKRDUTT
- Approach span-bridge layout plans and profile sheets Anchor: #LDQHQFEW
- Controlling vertical and horizontal clearance requirements Anchor: #SKVBQAPR
- Roadway geometry Anchor: #YGPQFEJV
- Design specifications used Anchor: #XGHGQUPI
- Special design criteria Anchor: #WGQXISNS
- Special provisions Anchor: #KFMSNNLS
- Cost estimates Anchor: #BBLOHQEK
- Hydraulic and scour design studies and reports showing scour prediction and related mitigation Anchor: #CAUFLNQC
- 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 Traffic Operations Division’s Rail Safety Section (TRF-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 TRF-RSS at least 12 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.
Examples of Exhibit A submittals are located at the following link: www.txdot.gov/inside-txdot/division/traffic.html