The project involved designing of two different types of Rigid pavements using the
AASHTOWare Pavement ME software.
1) JPCP (Jointed Plain Concrete Pavement) : It was designed as a three layered structure,
the layer distribution being as follows:
Layer 1 – PCC – 16 inch
Layer 2 – NonStabilized (Crushed gravel) – 8 inch
Layer 3 – Subgrade (A-1a) – Semi Infinite
Jointed plain concrete pavement uses contraction joints to control cracking and uses
reinforcing steel in form of dowel bars.
Transverse joint spacing is selected such that temperature and moisture stresses do not
produce intermediate cracking between joints.
This typically results in a spacing no longer than about 6.1 m (20 ft.).
2) CRCP (CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS) : It was
designed as a 4 layered structure, the layer distribution being as follows:
Layer 1 – PCC – 11.3 inch
Layer 2 – Stabilized – 4 inch
Layer 3 – NonStabilized – 8 inch
Layer 4 – Subgrade – Semi infinite
CRCP is concrete pavement reinforced with continuous steel bars throughout its length.
Its design eliminates the need for transverse joints (other than at bridges and other
structures) and keeps cracks tight, resulting in a continuous, smooth-riding surface.
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Design of a rigid pavement (jpcp & crcp)
1.
Design of a Rigid pavement
Team :
1) Ahsan ullah Hussaini Syed
2) Ahmed Towfeequllah Siddiqui
2.
Introduction
The project involved designing of two different types of Rigid pavements using the
AASHTOWare Pavement ME software.
1) JPCP (Jointed Plain Concrete Pavement) : It was designed as a three layered structure,
the layer distribution being as follows:
Layer 1 – PCC – 16 inch
Layer 2 – NonStabilized (Crushed gravel) – 8 inch
Layer 3 – Subgrade (A-1a) – Semi Infinite
Jointed plain concrete pavement uses contraction joints to control cracking and uses
reinforcing steel in form of dowel bars.
Transverse joint spacing is selected such that temperature and moisture stresses do not
produce intermediate cracking between joints.
This typically results in a spacing no longer than about 6.1 m (20 ft.).
2) CRCP (CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS) : It was
designed as a 4 layered structure, the layer distribution being as follows:
Layer 1 – PCC – 11.3 inch
Layer 2 – Stabilized – 4 inch
Layer 3 – NonStabilized – 8 inch
Layer 4 – Subgrade – Semi infinite
CRCP is concrete pavement reinforced with continuous steel bars throughout its length.
Its design eliminates the need for transverse joints (other than at bridges and other
structures) and keeps cracks tight, resulting in a continuous, smooth-riding surface.
3.
AASHTOWARE PAVEMENT ME
DESIGN USER INPUTS
The Pavement ME Design program
utilizes the user-defined inputs to
conduct a CRCP and JPCP mechanistic
analysis to predict the expected
incremental distress levels based on a
national calibration. As the Pavement
ME Design program represents a
fundamental change in design
philosophies in CRCP and JPCP design, it requires much greater knowledge of design parameters
affecting design including layer materials, climate, and traffic characterization. For users new to the
program, the following section outlines a basic overview of the program’s format and design
parameters. The Figure shows the main input screen of the Pavement ME Design program. General
input categories are viewed in the left of the screen while specific input parameters are viewed and
entered in the middle of the screen.
Figure 2 : Layer Structure & material properties – CRCP
Figure 1: Design user inputs for CRCP & JPCP –
AASHTOWare ME.
4.
Figure 3 Layer structure & material properties - JPCP
Traffic
To characterize the volume, the total amount of truck traffic is input as average annual daily truck
traffic (AADTT), including the expected lane and directional distribution factor for the facility.
Figure 4: Quarterly ADT distribution for Naples, Fl.
Ref : https://www.colliergov.net/modules/showdocument.aspx?documentid=58143
The AADT of Naples, FL was used to design the JPC pavement (With Dowel Bars), likewise
the AADT of Chicago, IL was used in the designing of the CRCP (Ref:
https://goo.gl/3OtCIY)
5.
CLIMATE
A key improvement to the CRCP design process is accounting for site-specific climate. The
Pavement ME Design program models account for daily and seasonal fluctuations in
temperature and moisture profiles in the CRCP and soil layer, respectively, through site-
specific factors such as percent sunshine, air temperature, precipitation, wind, and water table
depth. There are several hundred weather stations across North America from which the user
can select the nearest one to the project site, or the user can create a “virtual weather station”
by allowing the program to interpolate nearby weather data to the user’s specific project site.
Figure 5 : Ideal station can be picked to input Climate information
The pavement is then analyzed for :
a) IRI and Punchout in case of CRCP
b) Cracking, faulting & IRI in case of JPCP.
Post analysis, thickness is determined (Trial & error) for both the pavements.
Figure 6-7: Climate data for both the pavements.
6.
Result for JPCP
As far as terminal IRI is considered, Distress reliability of 122.56 was predicted from the
analysis against the targeted 172 which was well below the threshold. Similarly Joint Faulting
and Transverse cracking reliability criterion were satisfied.
The graphs above illustrate the achieved data for Cracking, Faulting and IRI and prediction
for a period of 30 years ahead.
By trial & error the thickness of the slab was found to be 16 inches.
7.
Result for CRCP:
Distress Type
Distress @
Specified
Reliability (%) Criterio
n
SatisfiedTarget Predicted Target Achieved
Terminal IRI (in./mile) 172.00 143.15 90.00 99.29 Pass
CRCP punchouts (1/mile) 10.00 3.99 90.00 99.95 Pass
As far as terminal IRI is considered, Distress reliability of 143.15 was predicted from the
analysis against the targeted 172 which was well below the threshold. Similarly punchouts
achieved a satisfactory 99.95% reliability.
The graphs above illustrate the achieved data for IRI & Punchout and prediction for a period
of 30 years ahead.
By trial & error the thickness of the slab was found to be 11.3 inches.
8.
KENPAVE
An analysis was carried out both the pavement types for Maximum stress using Kenpave.
CRCP
Slab thickness: 11.3 in ;
Dimensions: 12 x 12 ;
Reinforcement: 0.7%
Nodes : X : 0, 7, 14, 26, 50, 85, 120
Y : 0, 12, 36, 54, 78, 120
MAXIMUM STRESS (SMAX) IN LAYER 1 IS -95.112 ( NODE 2 )
MAXIMUM STRESS IN X DIRECTION = 0.0 ( NODE 0 )
MINIMUM STRESS IN X DIRECTION = 34.4 ( NODE 22 )
MAXIMUM STRESS IN Y DIRECTION = -95.1 ( NODE 2 )
MINIMUM STRESS IN Y DIRECTION = 13.4 ( NODE 5)
JCPC
Slab thickness: 16 in ;
Dimensions: 12 x 12 ;
Dowel bar: Dia: 1.25 in; Joint Spacing: 17ft
Nodes : X : 0, 7, 14, 26, 50, 85, 120
Y : 0, 12, 36, 54, 78, 120
MAXIMUM STRESS (SMAX) IN LAYER 1 IS -67.833 ( NODE 2 )
MAXIMUM STRESS IN X DIRECTION = 0.0 ( NODE 0 )
MINIMUM STRESS IN X DIRECTION = 24.2 ( NODE 43 )
MAXIMUM STRESS IN Y DIRECTION = -67.8 ( NODE 2 )
MINIMUM STRESS IN Y DIRECTION = 5.6 ( NODE 6 )
9.
Conclusion
JPCP
For a period of 30 years cracking is shown to be constant and gives a possibility of the
pavement life extending through 40-50 years as far as cracking is concerned. The
faulting rose from 0.02 during construction to 0.09 over a period of 30 years and may
only breach the threshold value after 40-45 years which again is well beyond the design
life. The IRI curve shows a linear relation for 25 years and the curve begins to flatten
out hence indicating an extended life than what it was being designed for.
CRCP
The IRI at the 30 year threshold is 143.15 (172 Max) and it keeps ascending and will
breach the target value round about the 45-50 year mark which is well ahead of our
target design life. The punchout starts at 2.2 and the curve ascends to about 3.99 till 15
years and henceforth remains constant till the target design life of 30 years and may
breach the limit well beyond the 50 year mark.