Drainage Feedback Report Summaries

For additional information e-mail: ltppinfo@fhwa.dot.gov.

Report Number: CAR-6
Date Submitted: 3/2/1998

Subject/IMS Table: Absence of data on effectiveness of pavement drainage systems in LTPP test sections.
Resolved: Yes
Last Updated: 7/19/2001

LTPP Analysis/Operations Situation: Complete evaluation of the effectiveness and value of pavement drainage cannot be conducted without knowledge of the degree to which drainage systems are functioning. Without this information the potential for inconclusive if not misleading conclusions is fairly high. Procedures should be developed and implemented to periodically evaluate how well the drainage systems are working with special emphasis on SPS-1 and 2.

Resolution of Problem/Situation: A drainage study on SPS-1 and 2 to be completed by June 2002 addresses this issue.

Report Number: KTH-1
Date Submitted: 6/11/2002

Subject/IMS Table: SPS-1 sections apparently lacking fabric separator between PATB and subgrade
Resolved: Yes
Last Updated: 1/03/2003

LTPP Analysis/Operations Situation: Core data and construction records should be reviewed to determine whether the SPS-1 test sections listed were indeed constructed without filter fabric, or whether a fabric was placed but is not recorded in TST_L05B and SPS1_LAYER. For any cases where a fabric or other separator is present but not recorded, TST_L05B and SPS1_LAYER should be updated accordingly. For the purposes of NCHRP Project 1-34C, a clarification of the presence or absence of fabric is requested for every SPS-1 section that includes a permeable asphalt-treated base (PATB).

Resolution of Problem/Situation: Initial investigations by the Technical Services Support Contractor revealed that these layers should be recorded in TST_LO5 and SPS#_LAYER but in many instances were not. The regional offices were instructed to review all SPS 1&2 construction documents and identify all test sections that have fabric separators and those that do not. The regional offices were instructed to furnish information directly to the NCHRP consultant, and to update TST_LO5 and SPS#_LAYER tables in the database.

Report Number: KTH-2
Date Submitted: 6/11/2002

Subject/IMS Table: SPS-2 sections apparently lacking fabric separator between PATB and subgrade
Resolved: Yes
Last Updated: 1/03/2003

LTPP Analysis/Operations Situation: A review of tables TST_L05B and SPS2_LAYER, conducted for NCHRP Project 1-34C, indicates that of the 56 core SPS-2 test sections with a permeable asphalt-treated base (PATB) — designs 0209,0210, 0211, and 0212, or designs 0221, 0222, 0223, and 0224, depending on the site — none was constructed with a filter fabric beneath the PATB. However, there are indications (e.g., North Carolina SPS-2 construction deviation report) that some of these sections may indeed have been constructed with filter fabric beneath the PATB.

Report Number: KTH-3
Date Submitted: 6/11/2002

Subject/IMS Table: Drainage placement apparently inconsistent with SPS-1 and SPS-2 experiment designs
Resolved: Yes
Last Updated: 1/03/2003

LTPP Analysis/Operations Situation: Construction records and other field notes and photos should be reviewed, and sites revisited as needed, to confirm the presence or absence of subdrains, and the locations of all outlets, in the SPS-1 and SPS-2 sections listed.

Resolution of Problem/Situation: The regional offices have reviewed and resolved the questions listed in this feedback report to the highest level possible, given the data available in their files. Some laterals were damaged by adjacent farming traffic. The missing laterals and headwalls are most likely buried and not functional. Some laterals were not constructed at exact spacing (± 20'). The extra outlets in the Arkansas SPS-2 could have been put in to ensure that the adjacent or nearby laterals are functional. These extra laterals are full of silt and gravel and inspection was unable to pass beyond 2-5 ft. They could also be old laterals not removed during construction.

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Data Collection Analysis Products Pooled Fund Studies Operations/Analysis Feedback Reports LTPP Customer Survey	Drainage Feedback Report Summaries For additional information e-mail: ltppinfo@fhwa.dot.gov. Report Number: CAR-6 Date Submitted: 3/2/1998 Subject/IMS Table: Absence of data on effectiveness of pavement drainage systems in LTPP test sections. Resolved: Yes Last Updated: 7/19/2001 LTPP Analysis/Operations Situation: Complete evaluation of the effectiveness and value of pavement drainage cannot be conducted without knowledge of the degree to which drainage systems are functioning. Without this information the potential for inconclusive if not misleading conclusions is fairly high. Procedures should be developed and implemented to periodically evaluate how well the drainage systems are working with special emphasis on SPS-1 and 2. Resolution of Problem/Situation: A drainage study on SPS-1 and 2 to be completed by June 2002 addresses this issue. Report Number: KTH-1 Date Submitted: 6/11/2002 Subject/IMS Table: SPS-1 sections apparently lacking fabric separator between PATB and subgrade Resolved: Yes Last Updated: 1/03/2003 LTPP Analysis/Operations Situation: Core data and construction records should be reviewed to determine whether the SPS-1 test sections listed were indeed constructed without filter fabric, or whether a fabric was placed but is not recorded in TST_L05B and SPS1_LAYER. For any cases where a fabric or other separator is present but not recorded, TST_L05B and SPS1_LAYER should be updated accordingly. For the purposes of NCHRP Project 1-34C, a clarification of the presence or absence of fabric is requested for every SPS-1 section that includes a permeable asphalt-treated base (PATB). Resolution of Problem/Situation: Initial investigations by the Technical Services Support Contractor revealed that these layers should be recorded in TST_LO5 and SPS#_LAYER but in many instances were not. The regional offices were instructed to review all SPS 1&2 construction documents and identify all test sections that have fabric separators and those that do not. The regional offices were instructed to furnish information directly to the NCHRP consultant, and to update TST_LO5 and SPS#_LAYER tables in the database. Report Number: KTH-2 Date Submitted: 6/11/2002 Subject/IMS Table: SPS-2 sections apparently lacking fabric separator between PATB and subgrade Resolved: Yes Last Updated: 1/03/2003 LTPP Analysis/Operations Situation: A review of tables TST_L05B and SPS2_LAYER, conducted for NCHRP Project 1-34C, indicates that of the 56 core SPS-2 test sections with a permeable asphalt-treated base (PATB) — designs 0209,0210, 0211, and 0212, or designs 0221, 0222, 0223, and 0224, depending on the site — none was constructed with a filter fabric beneath the PATB. However, there are indications (e.g., North Carolina SPS-2 construction deviation report) that some of these sections may indeed have been constructed with filter fabric beneath the PATB. Resolution of Problem/Situation: Initial investigations by the Technical Services Support Contractor revealed that these layers should be recorded in TST_LO5 and SPS#_LAYER but in many instances were not. The regional offices were instructed to review all SPS 1&2 construction documents and identify all test sections that have fabric separators and those that do not. The regional offices were instructed to furnish information directly to the NCHRP consultant, and to update TST_LO5 and SPS#_LAYER tables in the database. Report Number: KTH-3 Date Submitted: 6/11/2002 Subject/IMS Table: Drainage placement apparently inconsistent with SPS-1 and SPS-2 experiment designs Resolved: Yes Last Updated: 1/03/2003 LTPP Analysis/Operations Situation: Construction records and other field notes and photos should be reviewed, and sites revisited as needed, to confirm the presence or absence of subdrains, and the locations of all outlets, in the SPS-1 and SPS-2 sections listed. Resolution of Problem/Situation: The regional offices have reviewed and resolved the questions listed in this feedback report to the highest level possible, given the data available in their files. Some laterals were damaged by adjacent farming traffic. The missing laterals and headwalls are most likely buried and not functional. Some laterals were not constructed at exact spacing (± 20'). The extra outlets in the Arkansas SPS-2 could have been put in to ensure that the adjacent or nearby laterals are functional. These extra laterals are full of silt and gravel and inspection was unable to pass beyond 2-5 ft. They could also be old laterals not removed during construction. PDF files can be viewed with the Acrobat® Reader®	Shortcuts Distress Drainage FWD Friction GPS IMS Materials Profile SMP SPS Traffic Feedback Form Back to Feedback Events View all Upcoming Pavements Events Contact Customer Service 202-493-3035 E-mail Customer
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