Rigid Pavement Design Deficiencies

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Rigid Pavement Design Deficiencies

• Major shortcomings of JPCP designs based on
  1972-1986 versions of the AASHTO Guide
• inadequate joint load transfer,
• long joint spacing,
• erosion of base/subbase,
• poor subdrainage
• etc.
• Deterioration occurs early
• Rehabilitation needed

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Development of Supplemental AASHTO Design
Procedure for JPCP

• Serious deficiencies noted in 1986 AASHTO
  procedure
• Studies showed major flaws in base/subgrade
  support procedures
• No easy fixes
• Improved structural (3D finite element) model for
  JPCP was developed to correct deficiencies

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Development, Validation, Adoption 1998
Supplemental Rigid Pavement Design Procedure

• Developed under NCHRP Project 1-30
• (University of Illinois at Urbana-Champaign)
• Validated under FHWA/LTPP research study
• (ERES Consultants/ARA)
• Adopted by AASHTO as Supplementary Rigid Pavement
  Design Procedure (1998)
• FHWA/LTPP - Supplementary Rigid Pavement Design
  Spreadsheet (ERES Consultants/ARA)

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Only JPCP For Now
Jointed reinforced concrete pavement (JRCP) Contin
uously reinforced concrete pavement (CRCP)
Jointed plain concrete pavement (JPCP)

• Most constructed rigid
• pavement
• Basic design procedure
• developed
• Procedure field verified

• Limited field verification

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1998 AASHTO JPCP Design Is Better

• Improved structural modeling
• Improved subgrade characterization
• Base course as structural layer
• Transverse joint spacing
• Climate at site is considered directly
• Shoulder type and slab width
• Joint faulting and cracking checks

6
Use of LTPP Data to Verify1998 AASHTO Design

• Design procedure verified using field data from
  LTPP
• Inputs to 1998 AASHTO design model obtained
• Actual traffic log ESALs compared to predicted
  log W (ESALs)
• No significant bias found in predicting
  serviceability of pavements in four climatic zones

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PRESENTATION OBJECTIVES

• What is the Rigid Pavement Design (RPD) Software?
• Development of RPD Software
• RPD Software Features and Capabilities
• How To Use The RPD Software
• Who Should Use the RPD Software and Why
• How to Get the RPD Software

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Rigid Pavement Design Spreadsheet Features
Information sheet containing spreadsheet User
Guide
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Rigid Pavement Design Spreadsheet Features
Command buttons for easy navigation between sheets
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Rigid Pavement Design Spreadsheet Features
Command button links to reference tables
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Rigid Pavement Design Spreadsheet Features
Joint spacing and edge support conditions are
direct inputs
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Rigid Pavement Design Spreadsheet Features
Climatic properties are direct inputs in the
supplemental rigid pavement design
True subgrade k-value is used (not adjusted for
top-of-base)
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Rigid Pavement Design Spreadsheet Features
Easy links to sensitivity analysis for various
design inputs
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Rigid Pavement Design Spreadsheet Features
Project data can be saved in rows and exported to
the main sheets
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Rigid Pavement Design Spreadsheet Features
Sensitivity Analysis plot displays inputs held
constant
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Rigid Pavement Design Spreadsheet Features
Results sheet can be viewed on screen or can be
printed
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Rigid Pavement Design Spreadsheet Features
Calculation sheet shows all calculations and
displays design traffic for different slab
thicknesses
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Rigid Pavement Design Spreadsheet Features
Faulting Check sheet used to estimate faulting
over design life for doweled and nondoweled
pavements
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PRESENTATION OBJECTIVES

• What is the Rigid Pavement Design (RPD) Software?
• Development of the RPD Software
• RPD Software Features and Capabilities
• How To Use The RPD Software
• Who Should Use the RPD Software and Why
• How to Get the RPD Software

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Systems Requirements

• IBM PC running
• Microsoft Office 95 or 97 or
• Microsoft Excel 7.0

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Using The RPD Software

• Copy the Rigid Pavement Design (RPD) Software
  spreadsheet to the hard drive
• The RPD software cannot be run from the floppy
  drive
• Open the RPD spreadsheet using Microsoft Excel

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Using The RPD Software
Click on Enable Macros to allow execution of
spreadsheet macros
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Using The RPD Software
Click on Input Form to access the main sheet
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Using The RPD Software
Enter General Information for the project as
shown below
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Using The RPD Software
Scroll down to enter Serviceability and PCC
Properties
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Using The RPD Software
Click on Table 14 for friction factors for
different base types
Enter Base Properties, Reliability, and Standard
Deviation
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Using The RPD Software
Click on Input Form to navigate back to the main
screen
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Using The RPD Software
Enter Joint Spacing
Select Pavement Type and Edge Support Condition
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Using The RPD Software
Enter Climatic Properties for the design region.
Click on Table 15 for climatic properties for
major metropolitan areas in each State.
For the first run enter the approximate subgrade
k-value
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Using The RPD Software
Click on Calculate Traffic for traffic
calculation worksheet
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Using The RPD Software
After entering traffic design inputs click
Calculate
Click Export to Input Form
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Using The RPD Software
Click on Calculate on the main sheet to calculate
thickness for design inputs
Click on Calculate Seasonal k-Value for
calculating seasonally adjusted k-value
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Using The RPD Software
Enter number of months and subgrade k-value for
each season. Click Calculate.
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Using The RPD Software
Use the chart to estimate adjusted k-value for
fill layer above the subgrade and/or rigid layer
beneath the subgrade
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Using The RPD Software
Click on Calculate on the main sheet to
recalculate thickness for design inputs with the
adjusted k-value
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Using The RPD Software
Enter thickness for sensitivity analysis
Click Slab Thickness Sensitivity for sensitivity
analysis of design traffic to slab thickness
Click on radial buttons for sensitivity analysis
of design traffic to different design inputs
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Using The RPD Software
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Using The RPD Software
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Using The RPD Software
Click on Faulting Check to perform checks for
doweled and nondoweled faulting
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Using The RPD Software
Enter dowel diameter and other design inputs for
doweled pavements
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Using The RPD Software
Click on FI Table or Drainage Coeff. Table for
tables containing information regarding these
inputs
Click Calculate to obtain estimated faulting at
end of design life
Click Results to view and print results
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Using The RPD Software
Enter design inputs for nondoweled faulting check
and click Calculate
Click Corner Break Check to perform top-down
cracking analysis
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Using The RPD Software
The critical values for joint faulting can be
changed by entering the appropriate values below
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Using The RPD Software
On the Corner Break Check worksheet enter the
built-in temperature gradient related to
construction curling and moisture gradient
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Using The RPD Software
Use one of six charts provided to estimate
tensile stress at top of slab from total
effective negative temperature differential
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Using The RPD Software
The tensile stress at the top of the slab is less
than the bottom up tensile stress for which the
pavement is designed
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Using The RPD Software
Results sheet can be viewed on screen or can be
printed
Click Save Data to save the design information
entered
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Using The RPD Software
Enter ID for saving data and click OK
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Using The RPD Software
All design information is saved in rows with the
first column corresponding to the data set ID
Select appropriate row and click Export to export
design information from this sheet to main sheet.
This sheet can be accessed by clicking on
Retrieve Data on the main sheet.
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PRESENTATION OBJECTIVES

• What is the Rigid Pavement Design (RPD) Software?
• Development of the RPD Software
• RPD Software Features and Capabilities
• How To Use The RPD Software
• Who Should Use the RPD Software Why
• How to Get the RPD Software

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Users of the RPD Software

• State and Provincial Highway Engineers
• Consulting Engineers

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Benefits of Rigid Pavement Design Software

• Provides key answers not previously addressed
• How do I adequately characterize the subgrade
  support?
• What is the best base type for the conditions?
• What is the optimum joint spacing?
• Will this pavement fault or have corner breaks?

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PRESENTATION OBJECTIVES

• What is the Rigid Pavement Design (RPD) Software?
• Development of the RPD Software
• RPD Software Features and Capabilities
• How To Use The RPD Software
• Who Should Use the RPD Software Why
• How to Get the RPD Software

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Get Use The Software

• Order software
• -- Through LTPP homepage
• www.tfhrc.gov
• -- Through LTPP customer service
• Call 865-481-2967