Section 2: Overview of Policy
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The following table summarizes the pavement design and construction policies required by the department.
Section |
Policy |
Additional References |
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Chapter 2 Pavement Design Process |
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Section 2 Pavement Design Standard Operating Procedure (SOP) |
District SOP: The district pavement engineer (DPE) will review and update the District Pavement Standard Operating Procedures (SOP) on an annual basis. This SOP shall be reviewed and updated by September 1st annually with a copy emailed to MNT – Pavement Asset Management. If no changes are made from the previous year, send an e-mail to MNT – Pavement Asset Management confirming that no changes were made. |
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Pavement Design Communication: The district engineer (DE) is responsible for documenting communication channels for designing, constructing, and maintaining quality pavements. |
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Pavement Design Approval: Authority for pavement design approval may not be delegated below the DE, except for metropolitan districts. In metropolitan districts, pavement design approval authority may be delegated to the deputy district engineer, district director of construction, operations, or transportation, planning and development for projects with estimated construction costs of less than $20 million. |
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Section 3 District Pavement Engineer’s Role |
DPE: The DPE is a licensed professional engineer who serves as the district point of contact for the evaluation, preservation, and structural design of pavements. |
Section 3 lists general responsibilities for DPE. |
Training: The DPE is required to receive approved training in the use of MODULUS, FPS, AASHTO 1993 CPCD procedure, and TxCRCP ME design software. |
Other recommended courses for pavement materials and pavement management are included in this section. |
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Section 5 Pavement Type Selection |
Pavement Type Selection: The decision factors considered for pavement design type shall be included in the pavement design report. |
Section 5 includes some discussion on decision factors and recommends using the FHWA software RealCost to perform a life cycle cost analysis if warranted. |
Section 6 Approved Pavement Design Methods |
Pavement Design Methods: Use one of the following analytical methods for designing pavements:
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Refer to Chapter 5 for flexible pavement design specifics and Chapter 8 for rigid pavement design specifics. |
Section 8 Information Needed for Pavement Design |
Evaluate Existing Pavement Condition: The district will take adequate measures to properly characterize the existing functional and structural condition of pavements scheduled for rehabilitation. |
Section 8 contains a brief discussion of destructive and nondestructive testing. More information is contained in Chapter 4. |
Moisture Damage Mitigation: Department policy on mitigating moisture damage in pavements is evident in many ways, such as establishing a non-erosive base beneath rigid pavements, and establishing HMA QC/QA density requirements and stripping evaluation. |
Guidelines are provided for cases where retro-fitting edge drains may be beneficial. Information about internal (positive) drainage measures is provided in Section 8. |
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Ground Water: Another major source of free moisture into the pavement structure is ground water.The department’s policy is to intercept ground water outside of the pavement structure to eliminate its impact. |
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Section 9 Pavement Design Reports |
Projects Requiring Pavement Design and Pavement Design Reports: A pavement design and a pavement design report are required for the following projects that are over 500 ft. long:
The following list provides examples of special cases that do not require a full design report but do require documentation of the criteria and rationale for the strategy selected for projects greater than 500 ft. long:
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Completing Pavement Design Report: Follow procedures outlined in Table 2-5. Form 2088: Required to include form 2088, Surface Aggregate Selection Form, as part of the flexible pavement design only. Information from this form will determine the appropriate Surface Aggregate Classification (SAC) of the aggregate used for the final hot-mix asphalt (HMA) riding surface. |
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Chapter 5 Flexible Pavement Design |
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Section 3 FPS 21 Design Parameters |
FPS 21 Design Parameters: The required analytical method of flexible pavement design is FPS 21. Input the Design Parameters for flexible pavement as detailed in this section. |
Chapter 2, Section 6, and Table 5-1. |
Post Design Check: Check the design derived by FPS 21 for full-depth shear strength adequacy using the Modified Texas Triaxial Class (TTC) design method contained in the FPS 21 software. |
Tables 5-4 and 5-5. |
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Traffic Input: Traffic loading must be entered as the 20-yr. cumulative ESALs. A 30-yr. analysis period or longer is allowable, but the designer must still input the projected 20-yr. cumulative ESALs. |
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Section 4 FPS 21 Modulus Inputs and Backcalculation |
Modulus Inputs: Determine design modulus values as detailed in this section. |
Table 5-6 shows a range of typical design values for various new or reclaimed pavement layer materials. Use an input value that is indicative of the material likely to be used. For materials to remain in place, use backcalculated moduli, with adjustments as warranted. |
Backcalculation: Use the backcalculation procedure to determine modulus input values for in situ pavement materials when these materials are used as-is (unmodified) in FPS design. |
See list of considerations enumerated in Section 4. |
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Section 5 Pavement Detours and Pavement Widening |
Structural Design of Detours: The falling weight deflectometer (FWD) shall be used to evaluate the adequacy of any existing structure (e.g., shoulders or bypass routes) to carry detour traffic. Design detours using of the following strategies:
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Pavement Widening: Maintain the original cross-section for the widened portion. When the shoulder is to form part of a new lane, perform non-destructive surveys using the falling weight deflectometer (FWD). |
Additional detail is given in this section regarding design and location of widening joints for bound, unbound, and dissimilar cross-section widening. |
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Section 6 Perpetual Pavement Design |
Perpetual Pavements:
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Use limiting strain criteria given. Follow Table 5-6 details for each step. |
Chapter 8 Rigid Pavement Design |
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Section 1 Overview |
Selection of Rigid Pavement Type: The department policy is to utilize Continuously Reinforced Concrete Pavement (CRCP) for new or reconstructed rigid pavements in Texas. The criteria in Chapter 8, Section 1, list the applications where Concrete Pavement Contraction Design (CPCD) can be used instead of CRCP, at the discretion of the district engineer. |
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Performance Period: For rigid pavements, the initial pavement structure shall be designed and analyzed for a performance period of 30 yr. |
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Tied Portland cement concrete (PCC) shoulders: Use tied PCC shoulders. If it is not feasible to provide full-width tied PCC shoulders, use a minimum 2-ft. widened outside lane. The PCC shoulders must have the same thickness and the same base layers as the main lane pavement. |
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Concrete Pavement Standards: For CRCP, the steel reinforcement, joints, and other design details are governed by the CRCP standards. For CPCD, the dowel bars, tie bars, joints, and other design details are governed by the CPCD standard. |
Link for CRCP and CPCD standards: http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/rdwylse.htm. |
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Section 2 Approved Design Method |
Approved Design Methods: TxCRCP-ME Design program is the approved design method for CRCP. The 1993 AASHTO Guide for Design of Pavement Structures is the only approved design method for CPCD projects. |
Chapter 8, Section 3, Rigid Pavement Design Process for CRCP. Chapter 8, Section 4, Rigid Pavement Design Process for CPCD. |
Section 3 Rigid Pavement Design Process for CRCP |
Design Parameters: Input the Design Parameters for CRCP as detailed in this section. |
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Section 4 Rigid Pavement Design Process for CPCD |
Design Parameters: Input the Design Parameters for CPCD as detailed in this section. |
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Section 3 & 4 Pavement Design Processes for CRCP and CPCD |
Base Layer Requirements: The department requires one of the following base layer combinations for concrete slab support:
Width requirement of subgrade/base: The subgrade/base must be designed 2 ft. wider than the concrete slab on each side to accommodate slipform pavement equipment. |
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Section 5 Determining Concrete Pavement Thickness |
Determining Concrete Pavement Thickness: For CRCP designs, the input thickness should be in 1/2 in. increments. The minimum thickness for CRCP is 7 in., and the maximum thickness is 13 in. For CPCD design, the computed concrete slab thickness should be rounded to the nearest full or half inch. The minimum slab thickness for CPCD is 6 in., and the maximum thickness is 12 in. |
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Section 6 Terminal Anchor Joint Selection for Concrete Pavement |
Terminal Anchor Joint Selection for Concrete Pavement: Use the transverse expansion joint details at bridge approaches shown in the concrete pavement standards. Districts may develop a Special Specification to use wide-flange systems. The use of anchor lug systems is no longer allowed. |
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Chapter 9 Rigid Pavement Construction |
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Section 1-7 |
Rigid Pavement Construction: Construct the rigid pavement in accordance with the department’s Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. |
Items 360, 421, and 440. Link for CRCP and CPCD standards: http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/rdwylse.htm |
Chapter 10 Rigid Pavement Rehabilitation |
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Section 1-11 |
Rigid Pavement Rehabilitation: Repair the rigid pavement in accordance with the department’s Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges and the relevant Special Specification of the rehabilitation. |
Items 361 and 720. Link for Repair of Concrete Pavement Standards: http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/rdwylse.htm |
Chapter 11 Ride Quality |
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Section 1 Overview |
Ride Quality: Measure ride quality in accordance with the department’s Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. |
Items 247, 340, 341, 342, 344, 346, 347, 348, 360, and 585. Table 11-2 can be used to select the appropriate pay adjustment schedule. |
Chapter 13 Load Zoning and Super Heavy Load Analysis |
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Section 1 Overview for Load Zoning |
Executive Order: The department’s executive director sets load limits for individual roadway segments by issuing an Executive Order. MNT – Pavement Asset Management prepares and submits proposed Executive Orders to the executive director. |
Texas Transportation Code, §621.102. |
Section 2 Changing Load Zones on Roads |
Changing Load Zones: Follow the procedures in this section for changing load zones. |
See Table 13-1. |
Section 3 Emergency Load Zones on Roads |
Emergency Load Zones: The district shall notify MNT – Pavement Asset Management by telephone or e-mail that an emergency load restriction is required. |
See Table 13-2. |
Section 4 Changing Load Zones on County Roads and Bridges |
County Roads and Bridges: Counties must obtain department concurrence from the district engineer for proposed changes to county road and bridge load limits. |
Texas Transportation Code, §621.301. See Tables 13-3 and 13-4. |
Section 6 Super Heavy Load Evaluation Process |
Super Heavy Load Analysis: All super heavy loads must be permitted through the Motor Carrier Division (MCD) of the Texas Department of Motor Vehicles (TxDMV). Refer to this section for the required evaluation process. |
Texas Transportation Code, §623.071 and §623.142. See Figure 13-3. See section 5 for analysis background information. |
Section 8 Damage Claim Procedure |
Damage Claim Procedure: Refer to this section for the required procedure. |
Financial Management Policy Manual, Chapter 4, Section 10, “Claims by TxDOT Concerning Damage to Highway Property.” |
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Standard Operating Procedures for Responding to PIA Requests for PMIS and/or Skid Data
Pavement Management Information System data and skid data are sometimes requested through the Public Information Act. To be sure each request is handled in the same manner in every district, here are the procedures to be followed:
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- Requests for information under the PIA must be in writing and must include the requestor’s contact information. E-mailed requests must go through the department’s website. Anchor: #ULYCGRNS
- All requests involving a traffic accident or focusing narrowly on a particular roadway segment or date must be referred to the Occupational Safety Division to determine if the department has received notice of claim threatening a lawsuit. Anchor: #MQVCNMVW
- When documents are to be withheld, notify GCD and submit a copy of the request with any responsive documents to GCD as soon as possible. Adequate time must be provided to GCD so GCD can prepare a brief and request a ruling from the AG within ten business days. Anchor: #NOJTDJEA
- When documents are to be released, release them promptly. If you are unable to release the documents within ten business days, you must certify that fact in writing to the requestor and provide a date and hour within a reasonable time when the information will be available for inspection or duplication.