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Publication Number:  FHWA-HRT-12-051    Date:  August 2012
Publication Number: FHWA-HRT-12-051
Date: August 2012

 

Sample Guide Specifications for Construction of Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS)

 

SECTION 4. CONTRACTOR QC

4.1. DESCRIPTION

The contractor shall provide a QC system to ensure that all materials and workmanship meet the required quality levels specified. The contractor shall provide qualified QC personnel and laboratory facilities and perform QC sampling, testing, inspection, data analysis, corrective action (when necessary), and documentation as outlined below.

4.2. CONTRACTOR QC PLAN

Before the start of the work, the contractor shall submit a written QC plan for approval by the agency. The QC plan is not intended to be a generic document, but rather, it must be project specific. The plan should sufficiently document the QC processes of all contractor parties (i.e., prime contractor, subcontractors, and producers) performing work required under this specification.

4.2.1. QC Plan Submittal Requirements

The contractor shall be prepared to discuss the QC plan at the pre-construction conference, including the proposed submittal date, QC organization, and sources of materials.

The contractor shall submit one hard copy and one electronic copy of the QC plan for agency approval no less than 45 days prior to the start of any work activities related to GRS-IBS construction, including excavation. The contractor shall not start work on the subject work items without an approved QC plan.

4.2.2. QC Plan Format and Contents

The QC plan shall be structured to follow the format and section headings outlined below. The pages of the QC plan shall be sequentially numbered. The plan shall address, in sufficient detail, the specific information requested under each section and subsection.

Cover Page

Table of Contents

Section 1. Scope and Applicable Specifications

Section 2. Quality Control Organization

2.1 QC Organizational Chart
2.2 QC Personnel and applicable Qualifications
2.3 QC Self-Checks by Production Personnel

Section 3. Quality Control Laboratories

3.1 QC Laboratory Accreditation or Agency Qualification

Section 4. Materials Control Procedures

4.1 Material Types and Source of Supply
4.2 QC of Project Produced Materials Offsite
4.3 QC of Standard Manufactured Items
4.4 On-site Material Storage and Handling

Section 5. QC Visual Inspection

5.1 QC Procedures for Equipment
5.2 Definition of Lots and Sublots (for Inspection)
5.3 Attributes Inspected for Project Produced Items
5.4 Attributes Inspected for Standard Manufactured Items
5.5 QC Inspection Report Forms
5.6 Evaluation of QC Inspection Results

Section 6. QC Sampling and Testing

6.1 Definition of Lots and Sublots
6.2 Random and Selective Sampling Procedures
6.3 Sample Identification, Storage, and Retention
6.4 Quality Characteristics Tested for QC
6.5 QC Sampling and Testing Report Forms
6.6 Evaluation of QC Testing Data

4.2.3. QC Plan Approval and Modifications

4.3. QC PERSONNEL REQUIREMENTS

4.4. QC LABORATORY FACILITY REQUIREMENTS

4.5. QC OF STANDARD MANUFACTURED ITEMS

4.6. QC INSPECTION

The contractor shall perform QC inspection of all work items addressed under this specification. Inspection activities during production and placement may be performed by qualified production personnel (e.g., skilled laborers, foremen, and superintendents). However, the contractor’s QC personnel shall have overall responsibility for QC inspection.

QC inspection activities must address the following primary components: equipment, environmental conditions, materials, and workmanship. The minimum frequency of QC inspection activity shall be in accordance with the requirements below and as outlined in the approved QC plan.

4.6.1. QC Inspection of CMU Facing Element, Backfill, and Geosynthetics

The contractor’s personnel will perform QC inspection during installation of the CMU facing element, backfill material, and geosynthetics in accordance with the requirements of this specification. The minimum attributes to be inspected are outlined in table 2 and table 3. The contractor shall identify in the QC plan the specific inspection activities necessary to ensure the quality of the work, including any additional QC inspection attributes not specifically listed in table 2 and table 3.

Table 2. Minimum QC inspection of CMU facing element.
Inspection Component Attributes Inspected Minimum Inspection Frequency Point of Inspection Inspection Method
Equipment As specified in QC plan Per QC plan Per QC pan Per QC plan
Environmental conditions Underlying surface soundness and moisture Per QC plan Underlying surface Visual check
Temperature of air and underlying surface One per day At placement location Check measurement
Materials CMU blocks
(correct type)
Per QC plan Stockpile on site Visual check and manufacturer COC
CMU block
dimensions
Per QC plan Stockpile on site Check measurement
Reinforcing
steel bar
(correct type)
Per QC plan Stockpile on site Visual check and manufacturer COC
Concrete wall fill (correct type) Per QC plan At placement location Check concrete batch ticket
Workmanship CMU block course
(free of debris)
One per CMU course Each CMU course Visual check
CMU block fit (free of gaps) One per CMU course Each CMU course Check measurement or visual check
CMU block horizontal alignment One per CMU course Each CMU course Check measurement or visual check
CMU block vertical alignment One per two CMU courses Each two CMU courses Check measurement
Reinforcing steel bar alignment/cover One per top of wall or wall parapet At placement location Check measurement or visual check
Concrete wall fill finishing/curing One per top of wall or wall parapet At placement location Visual check
Concrete coping wall fill finishing/curing One per top of wall or wall parapet At placement location Visual check

 

Table 3. Minimum QC inspection of backfill material and geosynthetic reinforcement.
Inspection Component Attributes Inspected Minimum Inspection Frequency Point of Inspection Inspection Method
Equipment As specified in QC plan Per QC plan Per QC plan Per QC plan
Environmental Conditions Underlying surface soundness and moisture Per QC plan Underlying surface Visual check
Temperature of air and underlying surface One per day At placement location Check measurement
Materials Abutment backfill
(correct type and free of organics)
One per backfill layer At placement location Visual check
RSF backfill
(correct type and free of organics)
One per backfill layer At placement location Visual check
Integrated approach backfill
(correct type and free of organics)
One per backfill layer At placement location Visual check
Geosynthetics (correct type and free of tears) One per backfill layer At placement location Visual check and manufacturer COC
Workmanship Abutment backfill
(lift thickness)
One per backfill layer Post-compaction of each lift Check measurement
RSF backfill
(lift thickness)
One per backfill layer Post-compaction of each lift Check measurement
Integrated approach backfill (lift thickness) One per backfill layer Post-compaction of each lift Check measurement
Level of backfill behind CMU facing block One per backfill layer Post-compaction of each lift Visual check
Geosynthetics (embedment area coverage = 100 percent) One per backfill layer Each geosynthetic layer Visual check
Geosynthetics (coverage of top surface of CMU blocks > 85 percent) One per backfill layer Each geosynthetic layer Visual check
Geosynthetics (no excessive construction damage) One per backfill layer Each geosynthetic layer Visual check
Geosynthetics (splice seams staggered) Per reinforcement schedule Each geosynthetic layer Visual check

4.7. QC SAMPLING AND TESTING

The contractor’s QC personnel will perform QC sampling at the site of GRS field placement. QC testing will be performed at the field placement site or at the contractor’s QC laboratory depending on the quality characteristic being tested. The contractor shall furnish approved containers for all material samples. The engineer shall be provided the opportunity to monitor and witness all QC sampling and testing.

4.7.1. GRS Lot and Sublot Sizes

Each lot of GRS backfill material will represent material from the same source, be produced or obtained under the same controlled process, and will possess normally distributed specification properties. Each lot will be divided into sublots of equal size to assess the quality characteristics of the lot. The lot size and corresponding sublot size for each GRS backfill material item is listed in table 4.

Table 4. GRS backfill material lot and sublot sizes.
Backfill Item Material Type(s) Lot Size Sublot Size
Abutment backfill Well-graded aggregate Total quantity (cubic yard) of backfill material type/same source/abutment See table 5
Open-graded aggregate
RSF backfill Well-graded aggregate Total quantity (cubic yard) of backfill material type/same source/RSF See table 5
Integrated approach backfill Well-graded aggregate Total quantity (cubic yard) of backfill material type/same source/integrated approach See table 5

4.7.2. Random QC Sampling

The contractor’s QC system shall utilize stratified random sampling of each lot produced and placed. The contractor’s qualified QC personnel shall obtain random QC samples at the minimum frequencies specified in table 5. In all cases, the QC sampling frequencies shall result in a minimum of one random sample per sublot.

Random sample locations shall be determined using the random number tables and procedures contained in ASTM D 3665-07 or an electronic random number generator.(18) The determination of all random sample locations shall be documented on standard test report forms (TRFs). The contractor will provide the engineer with the random QC sampling locations for each sublot prior to production and placement of the relevant sublots.

4.7.3. Selective Sampling

The contractor’s QC system will also utilize selective sampling (i.e., non-random samples) as needed to provide supplemental information to assist in maintaining all production and placement processes in control. The contractor’s qualified QC personnel shall obtain selective QC samples from any sublot as determined necessary and in accordance with the guidelines established in the approved QC plan.

4.7.4. QC Sample Identification System

The contractor shall establish a reliable system for the identification of all QC samples obtained. All samples shall be correctly labeled with the following minimum information:

4.7.5. Retention of Split Samples

The contractor will retain split samples from each QC material sample and provide a split sample to the engineer if requested. All split samples shall be properly labeled and stored for a period of 30 days or until tested. These split samples will be utilized, if necessary, in the dispute resolution process. The retained split samples may be discarded prior to the required 30 days if mutually agreed on by the contractor and the agency.

4.7.6. QC Testing of GRS Lots

The contractor’s QC personnel will perform QC testing during production and field placement of the backfill material to ensure that the production and placement processes are providing work conforming to the contract requirements. All QC testing shall be in accordance with AASHTO, ASTM, or agency procedures specified in table 5. The engineer shall be provided the opportunity to monitor and witness all QC testing.

Table 5. Minimum QC sampling and testing of backfill material.
Quality Characteristic Test Method Sublot Size Minimum Test Frequency Point of Sampling Sampling Method
Gradation AASHTO T 11-05(6) and AASHTO T 27-05(19) One per lot Source of material(before use) Random; AASHTO T 2-91(20) and AASHTO T 248-11(21)
PI AASHTO T 89-10(7) and AASHTO T 90-00(8) One per lot Source of material (before use) Random; AASHTO T 2-91(20) and AASHTO T 248-11(21)
Maximum dry density and optimum moisture content AASHTO T 99-10(16) (method C) and AASHTO T 180-10(22)(method D) One per lot Source of material(before use) Random; AASHTO T 2-91(20) and AASHTO T 248-11(21)
In-place density and moisture content (per targets)* AASHTO T 310-11(23) (method B) and other approved procedures Minimum two per lift per day One per sublot In-place compacted backfill (before placing subsequent layer) Random; AASHTO T 310-11(23)
— Indicate that the there is no sublot size.
*If density requirements cannot be achieved due to material incapable of being compacted or tested to maximum values as determined by AASHTO T 99-10, compact each layer a minimum of four passes using vibratory compactor until there is no visible evidence of further consolidation.(16)

 

4.8. QC Documentation and Data Evaluation

4.8.1. QC Inspection Documentation & Evaluation

The contractor shall document all QC inspection activity for each GRS lot produced and placed. All inspection results shall be recorded within 24 h of inspection on current standard inspection report forms (IRFs). The QC manager shall evaluate inspection results in a timely manner to confirm that production and placement processes are in control. The contractor shall submit hard copies of all IRFs to the engineer at the completion of each lot.

4.8.2. QC Sampling and Testing Documentation and Data Analysis

The contractor shall document all QC sampling and testing data for each GRS lot produced and placed. All sampling and testing data shall be recorded within 24 h of sampling and testing on current standard TRFs. The QC manager shall evaluate sampling and testing results in a timely manner to confirm that production and placement processes are in control. The contractor shall submit hard copies of all TRFs to the engineer at the completion of each lot.

4.9. QC RECORDS SYSTEM

4.9.1. QC Daily Diary

The QC manager should maintain a QC daily diary to document all major activities or actions related to the contractor’s QC system. The QC daily diary serves as a summary record of key actions taken by QC personnel each day. Recommended information that should be recorded in the QC daily diary includes the following:

4.9.2. QC Record Books

The contractor shall maintain one or more ringed binders referred to as “QC record books” to store all required QC documents. Separate QC record books shall be kept at each GRS backfill material production facility and at the project field site. QC data for each pay item number shall be organized into separate sections by quality characteristic and by lot number. QC documents to be stored in the QC record book(s) include the following:

Each required record shall be inserted into the corresponding QC record book within 24 h after the document has been completed. All QC record books shall be maintained in a suitable location. The engineer shall be provided access to all QC record books as part of the agency’s monitoring of contractor QC activity.

4.9.3. QC Records Retention

All contractor QC records identified above shall be retained for a minimum of 3 years. The records shall be protected from damage or alteration. When requested by any State or Federal agency for audit or similar purposes, the contractor shall provide complete access to all QC records.

 

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