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CHAPTER 3. DATA BASE DEVELOPMENT
Introduction
In this project, two separate types of information were collected and stored In a
set of project data bases. These information types are agency survey data and project
analysis data. The agency survey data stem from the following three sources:
~, ,
NCEURP project 20-7 task 53 (Scofield 1992) 1992 Salt survey.
NCEURP project 1-31 1994 SELL survey.
NCHRP project 1-31 1994 selected paving contractor survey.
As discussed In chapter 2, the information In these surveys has been used to
determine current practices and opinions regarding initial pavement smoothness
specifications and testing procedures. In addition, the information has been used to
indicate the general direction that States are taking with regard to their specifications
and testing methods.
~i, ~
The project analysis data were used to evaluate He importance of initial
smoothness and the effectiveness of ~rutial smoothness specifications. These data
typically include pavement design, construction, and monitoring data on several
highway study sections and pavement projects available from the following sources:
.
Past roaci tests (e.g., American Association of State Highway Officials
[AASHO] Road Test, Western Association of State Highway Officials
[WASHO] Road Test).
On-going pavement performance studies (e.g., Long-Term Pavement
Performance [LTPP] program, FHWA's Rigid Pavement Performance and
Rehabilitation [RPPR] study).
· Selected SHAs.
The data are stored in He Microsoft Access data base management system. This
system was selected for a variety of reasons. First, it allows for quick and easy entry
of many types of data, as it is operable In bow spreadsheet and data form
environments. Second, like over powerful data base programs, it has virtually
unlimited capacity since it too operates as a relational data base. However, unlike
those other programs, Access features suppler querying and reporting procedures.
Most importantly, data contained in Access are easily exportable into Microsoft Excel
_ _1_ ~ _1 ~ _ .1 ~
wn~ch) tor tins project, serves as a secondary data base manager. The computerized
worksheet available in Excel not only allows quick statistical analyses and preparation
of graphs, but also reduces concerns about being able to accurately query and
retrieve data.
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Description of Data Bases
Agency Survey Data Bases
Work on the agency survey data bases was initiated with the establishment of the
NCHRP 20-7 task 53 State survey data base. The tables In this data base were
structured such that States are listec! In the first column and the survey questions are
listed, in order, in the column headings to the right. The State responses were then
manually entered into the appropriate cells.
Once He NCHRP I-31 State survey form was completed, the data base for this
survey was fully structured using the same format as the NCHRP 20-7 survey data
base. As State responses became available, the results were again manually entered
into the appropriate cells.
As part of the agency surveys, selected paving contractors were contacted in order
to obtain the contractor's perspective on pavement roughness measuring procedures
and practices. Both AC and PCC paving contractors were contacted. The same
procedure for the clevelopment of the agency survey data base was followed for the
contractor data base.
Project Analysis Data Bases
Work on the project analysis ciata bases began with the development of a list of
anticipated data base elements. This list, shown in table 7, was prepared following
the Strategic Highway Research Program (SHRP) LTPP Data Collection Guide (FHWA
1993), and contains the necessary data elements for conducting later analyses to
address the following key project objectives:
i. Determine the effect of initial smoothness on the ride quality of the pavement
over its life and on pavement service life.
2. Determine the effect of existing smoothness specifications on He initial as-
constructed smoothness.
3. Determine He cost-effectiveness of smoothness specifications, including
incentives and disincentives.
Sources of Data for Project Analysis Data Base
Past Road Tests
AASHO Road Test
The AASHO Road Test represents one of the most comprehensive studies of
pavement performance that has ever been conducted. Over 800 AC and PCC
pavement study sections were constructed and evaluated from 1958 to 1960.
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Table 7. Initial list of anticipated data base elements.
Section Identification
-
State
Project number
Highway number
County
City
Beginning station/milepost
Ending station/milepost
Direction of travel
Functional classification
Number of Peru lanes
Construction date
Pavement Design Information
Pavement type
Pavement structure (layers and thicknesses)
Maintenance and Rehabilitation Information
Activity description
Date perfo~ed
Begnunng location
Ending location
Extent of activity
Distress Monitoring Information
Year of measurement
Distress types, severities, and quantities
Traffic Monitoring Information
Cumulative 18-km ESALS
Average daily traffic (ADT 2-way)
Average daily truck traffic (ADTI 2-way)
Initial Roughness Information
Equipment type and model
Time performed after construction
Loners) tested
Unit length of paving section tested
Positionts) tested
Number of passes made per position
Method of equipment calibration
Roughness index used
Roughness measurements
Extended Roughness Information
Equipment type and model
Dates of testing
Lanes tested
Unit length of paving section tested
Positions tested
Number of passes made per position
Method of equipment calibration
Roughness index used
Roughness measurements
T~e-series serviceability data, based largely on slope variance measurements made
win a longitudinal profiling device, were obtained for all of the sections.
The AASHO Road Test data were obtained and entered into Excel spreadsheets.
Rigic} pavement section data, such as pavement design, loading information, and
present serviceability ratings (PSRs), were manually entered from appendix A of The
AASHO Road Test Special Report 6IE (AASHO 1962~. Only He data for replicate
study sections were entered, as only Hose sections allow for the direct comparison of
serviceability trends. In addition, He PSRs provided In Special Report 6lE are
smoothed ratings and represent only a portion of He ratings that were typically
assigned on 2-week intervals over the 2-year study period.
Sunilar data on the flexible pavement sections were obtained from a computerized
ASCH file and were Imported into Excel. Unlike He rigid data, however, the flexible
data contained cumulative load applications and unsmoothed serviceability ratings
assigned at the specified 2-week intervals. I~ike before, replicate sections were then
extracted from He original data file and placed into a second data file for direct
· ~
examination.
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WASHO Road Test
Test data from the WASHO Road Test on various conventional AC pavement
designs were found In The WASHO Road Test Part 2 (HRB, 19551. These data
included initial anc! extended roughness measurements for the years of the road test
(October 1952 through May 1954) using a Bureau of Public Roads (BPR) Road-
Roughness Indicator. The roughness measurements, and corresponding load
applications, of forty 300-ft (91.5-m) experimental sections were entered into Excel for
analysis of roughness trends.
San Diego County Test Road
Test data on various AC pavement sections constructed as part of the San Diego
County Experimental Base Project were also unearthed (Shook, 1976~. A total of 35 test
sections, having different base types and Sicknesses, were included In this
experunent, which was begun In 1966 and discontinued in 1973. The prime interest
In this experiment was He serviceability trends of similar sections, as defined by
cumulative equivalent IS,000-Ib (80-kN) s~ngle-axie loads (ESALs) and present
serviceability index (PSI) calculations (determined In part by slope variance
measurements made with the ChIoe profiler).
Alabama Pavement Roughness Study
A pavement study done by the Alabama Highway Department in the 1960s also
yielded roughness data for analysis in the NCHRP 1-31 project (Holman, 1969~. This
study involved initial and extended roughness testing of several AC and PCC
pavement projects located on various Alabama highways. The roughness
measurements were made with the BPR Road-Roughness Indicator on 0.5-mi (0.~-km)
intervals, thereby resulting In time-series measurements for multiple, f~xed-~nterval
highway sections. As with the other road tests, pertinent data were extracted from
He report and entered Into Excel.
Minnesota Flexible Pavement Design Study (Investigation IS3)
In 1963, the Minnesota DOT began a study of many ~n-service, flexible pavement
sections located on various trunk highways throughout the State (Kerston and Skok
1968~. The purpose of the study was to evaluate the flexible pavement design
procedures used by the department at that time and to determine how He findings
and concepts of the AASHO Road Test could be applied to their pavement design
procedures.
A total of 50 pavement sections, built or overlaid in He late 1950s and early 1960s,
were identified and monitored for performance Trough 1967. The sections were
conventional AC designs, with asphalt layer thicknesses ranging mostly from 1.5 to
7.5 in (38 to 190 mm) and granular base layer thicknesses ranging from 6 to 22 in
(150 to 560 mm). Roughness measurements were made win He BPR Roughometer,
both at the time of construction and during each of the 5 years (1963 through 1967)
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that the sections were evaluated. Pertinent data were extracted from the report and
entered into Excel for analysis.
On-Going Pavement Performance Studies
LTPP
The LTPP program is a coordinated, 20-year nationwide study of pavement
performance. The program consists of General Pavement Studies (GPS) and Specific
Pavement Studies (SPS). The GPS is of ~n-service pavements and consists of 866
flexible and rigid sections. The SPS is targeted at specific issues In pavement
performance and contains specially constructed sections.
A COpy of release 6 of the GPS data base was obtained in January 1995, with
submission of nearly complete data tables for all nine GPS experunents (i.e., GPS-!
through GPS-9~. A major problem noted with the GPS data was the absence of nutial
roughness measurements. For every GPS section, only extended roughness
measurements for the years 1989 through 1993 were available. Although the recent
SHRP P020 project (Daleiden, et al., 1994) was found to contain estimates of initial
PSIs for many of the GPS test sections (the PST data were either calculated from
initial roughness measurements, extrapolated and calculated from subsequent
roughness measurements, or estimated using project records, specifications, or
personal experience), the estimates were not deemed reliable enough to use for
analysis. To make use of at least some of the data, however, several GPS sections
built after 1986 were identified for possible analysis. Consideration was given to
allowing He first LTPP roughness measurements (1989 and 1990) to serve as the
Initial roughness values for these sections, despite a lag of up to 3 years following
construction.
In November, 1994, and October, 1995, attempts were made to collect and
evaluate LTPP SPS data. However it was found that the data were either not
available or had not passed the minimum level of quality checks.
RPPR
An on-going study being conducted for He Federal Highway Adm~rustration
(FHWA) on rigid pavement performance is another source of data for the NCHRP
1-31 project (Smith, et al., 1995~. Pavement sections in He RPPR study range between
12 and 27 years in age and differ foremost by pavement type, cross-section, and base
type. Initial and intermediate roughness measurements were made on some of the
sections using measuring devices that varied from State to State. In 1992, roughness
measurements were made on all sections using a South Dakota-type profiler.
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Selected State Highway Data
Although the above sources provided data useful to the study, the SHAs were the
primary focus In the data collection and analysis process. To help identify candidate
sources) agencies were asked the following questions on the State survey:
Type of roughness measuring equipment used on new construction?
Type of roughness measuring equipment used for extended monitoring?
~ Availability of iriitial roughness data on AC, PCC, and AC overlay pavements?
· Availability of extended roughness data on AC, PCC, and AC overlay
pavements?
Agency's willingness to provide roughness data for examination?
.
Based on the responses to these questions, several States were identified as potential
sources for supplying pavement project data.
In anticipation of soliciting data from selected SHAs, a two-part data request
package was developed, which consisted of a statement of request for pavement
project data, a synopsis of He current study, and a detailed list of the types of data
needed for several pavement projects.
The first part of the data request package pertained to the solicitation of initial
and extended pavement roughness data. These data were to be used In the analysis
of initial pavement smoothness versus both ride quality over a pavement's life and
pavement service life. Pavement projects targeted in this request included those with
specific pavement designs (e.g., AC full-depth, CRC) that are largely available In the
selected State and have been in service for several years.
The second part of the data request package pertained to the solicitation of
comprehensive pavement design and construction data. These data were to be used
In analyzing the effect of initial smoothness specifications on Initial smoothness and
in assessing He cost-effectiveness of crucial smoothness specifications. Pavement
projects targeted in this request included those with specific pavement designs built
both before and after the unplementation of a smoothness specification.
In order to gauge the difficulty of obtaining He required data and to better
estimate the number of States to ultimately target, He research team ~rutiated pilot
data collection efforts with He Illinois Depar~anent of Transportation (DOT) and the
California DOT (i.e., CALTRANS). The data collection experiences at bow agencies
provided the team win a better sense of the types of data that could reasonably be
requested.
Two separate data collection rounds were made in order to maximize the amount
of data for analysis. The following summarizes the results of those data collection
efforts carried out win the selected SHAs.
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IZZinois
The Illinois DOT provided historical files containing roughness measurements
taken of newly constructed highway pavements built throughout Illinois between
1959 and 1990. These roughness measurements were taken with the BPR
Roughometer along I-mi (~.6-km) intervals keyed by station number.
Extended roughness data were also available for all interstate highways. As such,
several interstate sections, having BPR Roughometer test results, were identified for
examination. Each of these sections were at least 5 mi (S km) in length so that the
roughness trends of multiple replicate sections (i.e., sections with the same design,
traffic, and climate) could be examined. Data tables were developed for each of these
projects that inclucled general information (e.g., location, clesian, etc.) about each
project, as well as the initial roughness measurements.
-c' ~
The extended roughness data kept by the Illinois DOT consisted of IRI
measurements keyed by milepost and taken on 0.~-mi (0.16-km) Intervals using a
Soup Dakota-type profiler. Extender] roughness measurements for the subject
interstate projects for the years 1990 through 1993 were furnished by Me DI~nois DOT
in hardcopy form. These data, along with pavement monitoring data obtained from
the Illinois Pavement Feedback System (IPFS), were then entered into the data tables
previously created.
The majority of projects selected for analysis from Bl~nois were CRC. Of 41 total
projects, 37 were CRC, 2 were AC overlays on CRC, and 2 were AC overlays on JRC.
Although several IRC paving projects were completed In the early 1960s, all of those
projects have since been overlaid two or three times.
California
In conjunction with the Illinois data collection effort, a series of visits were made
to CALTRANS to determine the availability and suitability of their data. Through
these visits, it was learned that the historical roughness data was generally not
adequate for analysis. This determination was made during the process of obtaining
and examining a sampling of historical roughness data on several highway projects In
District 8. Among the reasons for excluding these data were the following:
.
.
,~
No specific initial roughness values were available for projects older than 2 to
3 years. All PCC pavements and some AC pavements were built to meet a
specified roughness level (profile index < 7 ~n/mi [0.~! m/km] for PCC and
< 5 in/ml ro.os m/km] for AC) and the resulting orofilo~ranh test orc~file.s
_ _ , , , _ , _, ~ ~_
were typically retained for only 2 to 3 years.
~. ~
-to A- o---r-- ---- r------
Extended roughness testing was not performed consistently on a fixed-~nterval
basis. Extended roughness measurements were begun by the Pavement
Management Division in 1978. A fleet of PCA Roadmeters was deployed
every 2 years to monitor the roughness of every lane-mile of highway
pavement in California. Depending on the relative roughness of a project,
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measurements were made on intervals between ~ and 3 mi (~.6 and 4.83 km)
long. Maintenance treatments and rehabilitation work for portions of a given
pavement project further compounded the ability to generate accurate time-
series roughness data.
Arizona
The Arizona DOT provided an initial data package contairung historical roughness
data on 12 highway projects. This package included three individual paving projects
for each of four general pavement designs (AC, JPC, AC/AC, and AC/JPC). Each
project inclucLed initial and extended roughness measurements taken on 1-ml (~.6-km)
intervals using the Mays Meter. General information (e.g., location, design), traffic
estimates, and conclition survey data was also provicled for each project.
The Arizona DOT provided a second data package containing historical roughness
data on ~ additional highway projects (2 JPC, 3 AC, and 3 AC/AC). As with their
first package, each project included initial and extencled roughness measurements
taken on 1-ml (~.6-km) intervals using the Mays Meter. Likewise, general
information on each of these projects was also provided.
Georgia
The Georgia DOT also provided historical roughness data in response to both data
requests. Their first package included data on 12 individual paving projects-three
projects for each of the same four pavement designs (AC, lPC, AC/AC, and AC/JPC)
proposed by the Arizona DOT. Their second package included data on three AC/AC
projects and three AC/JPC projects. Each of the 18 total projects Included initial and
extended roughness measurements taken on I-mi (~.~km) intervals using a modified
Mays Meter. General project information, traffic estimates, and maintenance
Information were also furnished for these projects.
Comprehensive initial roughness data for the State of Georgia was contributed to
the study shortly after its outset. These data, which consisted of summary-type
roughness measurements for all new construction and resurfacing projects occurring
between 1980 and 1995, were entered into Excel for the purpose of examining the
effects of initial smoothness specifications on initial pavement smoothness.
Additional statewide initial roughness trends, spanrung the years 1968 through 1980,
were also made available for analysis.
Towa
Historical roughness data on Free JPC pavement projects were submitted by Me
Iowa DOT. Initial roughness measurements for these projects were made with the
California profilograph on 0.~-mi (0.16-km) intervals, whereas extended roughness
measurements were made with the International Cybernetics Corporation (ICC) MDR
4090 South Dakota-type profiler on 0.025-mi (0.04-km) intervals. General information
and traffic estimates were also provided for these projects.
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Iowa also possessed comprehensive initial roughness data. Various summary-
type roughness data were provicled by the Iowa DOT for new AC and PCC
construction and AC resurfacing projects completed between 1982 and 1993. These
data included California profiIograph measurements, South Dakota profiler
measurements, and BPR Roughometer measurements of both primary and secondary
highway facilities.
Kentucky
The Kentucky Department of Highways (DOH) provided pavement management
evaluation forms on nearly all interstate and parkway pavement projects in Kentucky.
These forms contained general project Information, condition survey results, and
summary-type rideabilitr indexes (RI) computed annually from the time of
construction. The RIs were derived from roughness measurements taken by
response-type road roughness measuring systems (RTRRMS), the most recent of
which is the Mays Meter.
Detailed RIs for 20 selected Interstate and parkway projects were also provided by
the Kentucky DOH. These projects, which included four different pavement types
JPC, AC, AC/JPC, and AC/AC), were all constructed after 1980 when Mays Meter
test results for I-mi (~.6-km) evaluation Intervals became available.
Michigan
A total of 47 Interstate and primary highway projects throughout Michigan were
originally identified for historical roughness analysis. These projects included IS PCC
pavements, 17 AC pavements, and 12 AC/PCC pavements, built during He 1970s
and mid 1980s. The extended roughness data obtained during He on-site visits were
for the years 1989 Trough 1994, and were made on 0.~-mi (0.16-km) intervals using a
GM ProfiIomeler~. Although, it was later discovered that nutial roughness data were
unavailable for many of the sections, a few of the original 47 projects those with
time lapses between construction and the first roughness measurement of 3 years or
less were stiD considered In He analysis.
Minnesola
A total of 26 AC, PCC, and AC overlay construction projects were identified In
Minnesota, located on various Interstate, U.S., and State highways. A summary of
the data provided by Minnesota includes the following:
GM ProfiIometer~ root-mean-square (RMS) and BPR Roughometer roughness
index data on I-mi (~.~km) Intervals for all selected PCC projects.
Time-series IR] (South Dakota-type profiler) and PSR data on 1-ml (~.6-km)
intervals for all selected projects.
Traffic data for all selected projects.
Distress (surface rating [SR]) data for all selected projects.
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Cross-section and construction/rehabilitation data were also made available.
Since lime-series IR] data were only available starting In 1989 and since
construction acceptance testing of AC (new and overlay) projects was not formally
begun until 1995, AC project selection focused on the construction years of ~ 988
through 1991. This way, the time lapse between construction and the first roughness
measurement was usually limited to 2 years and at least 4 to 5 years of roughness
trends could be analyzed.
The selected PCC projects consisted of pavements built between 1985 and 1991.
These projects were tested for construction acceptance using a GM ProfiIometer~ and,
in a few instances, the BPR Roughomeler.
Washington
The Washington DOT provided historical roughness data on various interstate
and primary highway projects throughout Washington state. These data included
test results from various pieces of inventory testing equipment used over the years by
the pavement management group. From about 1972 through 1976, a Mays Meter was
used to measure roughness (on 1-ml [~.~km] Intervals) of highway pavements every
other year. Then, from 1977 through 1990, a Cox PCA Roadmeter was used on an
annual or biennial (every two years) basis to measure roughness on the same
Interval. Finally, starting in 1991, a South Dakota profiler was used annually to
measure roughness on 0.~-mi (0.16-km) intervals.
A total of 22 AC, PCC, and AC overlay projects were selected for analysis, win
most being built In the mid to late 1970s and the early to mid 1980s. Cross-section,
traffic, and ma~ntenance/rehabilitation data for the selected projects were obtained In
conjunction with the time-series roughness data.
Although Washington has tested new PCC pavements for construction acceptance
since about 1973 (using the California profiIograph), these records were not available.
However, nearly all of the projects included pavement management tests performed
within 2 years of construction.
Wisconsin
The Wisconsin DOT provided a substantial amount of roughness and
serviceability data on several interstate and trunk highway projects In Wisconsin.
Other key types of data, including cross-section, traffic, distress, and
maintenance/rehabilitation information, were also available.
The PS] data spanned the years 1980 to 1995, with interstate projects having
annual measurements and Me trunk highways having measurements every other
year. The PST data for the years 1980 through 1989 were computed from Wisconsin
(Mays) Road Meter roughness measurements using statistically derived conversion
equations. Starting In 1990, a South Dakota-type profiler was used to measure
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roughness, which likewise was converted to PST using regression equations. In most
instances, the first roughness/serviceability measurement for post 1979 construction
projects was taken the same year that the project was opened to traffic. Some
projects, however, were noted as having the first measurement the year following
construction completion.
Summary
Many data sources were tapped In order to obtain useful historical roughness data
for examination under this study. Not all of the anticipated data were obtained, but
those that were obtained were thoroughly processed and entered into a data base. A
summary of the data base development effort is provided In table S. This table
shows the types of data that were targeted from We various sources and the status of
the data compilation work.
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Table S. Summary of data sources for analysis data base.
~Type of Data ~Data Received, Processed, ~
lData Source ~Available | Analyzed l
AASHO Road Test ~Serviceability Yes
WASHO Road Test ~Roughness Yes
San Diego County Road Test ~Serviceability Yes
~ Alabama Roughness Study ~Roughness Yes ~
l Minnesota Investigation 183 ~Serviceability Yes l
_ v
LTPP GPS I Roughness 1es
l RPPR l Roughness . es l
1 Arizona l Roughness Yes l
l Georgia T Roughness Yes l
l Illinois l Roughness Yes l
~Iowa r Roughness Yes l
l Kentucky l Roughness Yes ~
1 Michigan l Roughness Yes l
l Minnesota l Roughness Yes l
l South Dakota l Roughness Yes l
l Washington l Roughness Yes l
I . l Serviceability Yes l
Wisconsin l (some roughness) l
40
Representative terms from entire chapter:
roughness data
