contractor quality control tests using for acceptance

CONTRACTOR QUALITY CONTROL TESTS USING FOR ACCEPTANCE by Gary Doyle Deputy Director - Construction Louisiana TIMED Managers

History and Purpose of TIMED • Transportation Infrastructure Model for Economic • • • •

Development Connect major cities of Louisiana with four lane highways Bridge crossings to promote connectivity Enhance economic development Funding for intermodel enhancements

History • Established by Act 16 of the 1989 Legislature (endorsed

• • •

by vote of the people) Sixteen major projects (constitutionally enumerated) 4 cent additional gasoline and special fuels tax authorized Tax to expire in 15 years (2005)

Additional Enabling Legislation •

ACT 64 of 1998 • Extended the Act 16 taxes until TIMED Projects complete or debt repaid • Allowed for project estimate revisions

•

ACT 1 of 2000 • Extended the opportunity to issue revenue bonds from 2005 to 2010 • Extended the allowable bond maturity term from 20 to 30 years

Overview NOIA US 167

W. Napolean

US 171

Earhart Blvd. Florida Ave.

LA 15 Port of N.O. US 165 WB Expwy St. Francisville US 61

LA 3241 US 90

Tchoupitoulas

Huey P. Long

LTM’s Role • Program Management through innovative concepts • Financial Planning & Management • Design Oversight • Right-of-way Management and Acquisition • Utility Relocation • Identification and Assessment of Contaminated Sites

•

and Corrective Action Construction Administration Services

LTM Construction Administration • • • •

• •

Field Engineering and the CDC Use of contractor’s Schedule Computers in the field Continuous communication between the field, area office and central office Performance driven Increased Emphasis on contractor QC

QC / QA - Acceptance • Quality Control (QC) • Process Control - those actions and considerations necessary to assess and adjust production and construction processes so as to control the level of quality being produced in the end product.

• Acceptance • Sampling and Testing, Inspection and other documentations - to determine the degree of compliance with contract requirements.

• Quality Assurance (QA) • QA is a combination of QC and acceptance. All those planned and systematic actions necessary to provide confidence that a product or facility will perform satisfactorily in service.

Field Testing • • • •

Quality Efficiency Innovation Make better use of contractor’s QC testing

DOTD Quality Control Procedures

Specification CONTRACTOR QUALITY CONTROL: Subsection 106 is amended as follows: Delete the second paragraph and substitute the following: Quality Control requirements shall be as specified in the appropriate specification section and as specified in the latest edition of the Departments “Quality Control / Quality Assurance Manual.” In case of a discrepancy, the project specifications govern over the manual. The contractor shall perform sufficient testing to assure that his processes are providing work in accordance with the plans and specifications. The minimum frequency of quality control testing shall be equal to or greater than the minimum frequencies shown for acceptance in the DOTD Materials Sampling Manual. The results of the contractor’s tests shall be furnished to the engineer on a routine basis, usually daily, and upon completion of an item of work, a summary of the quality control tests shall be provided to the engineer.

Use of QC Test for Acceptance FHWA 23 CFR 637B (6) states the following: • Quality control sampling and testing results may be used as part of the acceptance decision provided that: • The sampling and testing has been performed by qualified

•

laboratories and qualified sampling and testing personnel. The quality of the material has been validated by the verification testing and sampling. The verification shall be performed on samples that are taken independently of the quality control samples.

Qualified Personnel • Certified Inspectors required • DOTD specifications require contractor to use

•

qualified/certified technicians DOTD training requirements

Field Testing • Using contractor’s Quality Control tests in the

• • • •

acceptance decision. Contractor is performing Quality Control testing. LTM is performing Acceptance and/or Verification Testing. If verified, use contractor QC for acceptance and reduce verification testing frequency If not verified, continue acceptance testing at prescribed frequency

Earthwork Compaction Testing Locations for QA Tests • 1000 ft Zones • Testing Frequency = 1 test/lift/zone  100+00

 101+00

Zone 1

 102+00

Zone 2

 103+00

Zone 3

 104+00

Zone 4

QA Tests in Multiple Lift Areas • Not just reduced QA • Contractor QC must be considered as acceptance Zone = 1000 ft Zone = 1000 ft

Excavation Excavation Excavation

Embankment Embankment

QA Tests in Multiple Lift Areas • Test 1 &2 Zone = 1000 ft Zone = 1000 ft

Excavation Excavation

Excavation

T-1 T-2 T-1 T-2 T-2 T-1


QA Tests in Multiple Lift Areas • Test 3 & 4 Zone = 1000 ft Zone = 1000 ft

Excavation Excavation Excavation T-3 T-3 T-1 T-1

T-1

T-4T-4 T-2 T-2

T-2

 T

2


QA Tests in Multiple Lift Areas • Test 5 & 6 Zone Zone == 1000 1000 ftft


T-5 T-5

T-3 T-4 T-3 T-4 T-2 T-1 T-1 T-2


T-6 T-6



T-7 T-7 T-8 T-8

T-5 T-5

T-3 T-3 T-4 T-4 T-1T-1 T-2 T-2


T-6 T-6



T-8 T-7 T-7 T-8 T-3 T-4 T-3 T-4 T-1 T-1 T-2

T-10 T-9 T-10 T-9 T-5 T-6 T-5 T-6


QC Test Report

QA Test Report

Statistical Verification • F-test

100

97.5

95

02/14/04

02/07/04

01/31/04

01/24/04

01/17/04

01/10/04

Date

01/03/04

12/27/03

12/20/03

12/13/03

12/06/03

11/29/03

92.5

11/22/03

• Determines if two samples are likely to have come from the same underlying populations that have the same mean.

QC / QC Comparison

11/15/03

• T-test

102.5

Percent

• Determines the probability that the variances in one group of tests is not significantly different than the variances in another group of tests.

QC/QA Comparison Tests Date Tested 11-26-03 12-03-03 12-12-03 12-20-03 12-20-03 12-21-03 01-07-04 01-07-04 01-12-04 01-12-04

Station Tested 201+65 186+00 400+00 405+30 400+00 207+50 182+00 389+50 181+75 182+25

Section & Test No. 01-0001 01-0002 05-0001 05-0002 05-0004 01-0003 01-0004 05-0005 0001-06 0001-07

Field Moisture 14.0% 12.2% 13.7% 14.0% 15.8% 13.4% 16.8% 17.0% 14.7% 14.7%

Percent Density (QC) 97.8% 96.9% 98.3% 96.9% 95.1% 96.2% 95.3% 95.2% 97.8% 97.4%

Date Tested 11-26-03 12-03-03 12-12-03 12-20-03 12-20-03 12-21-03 01-07-04 01-07-04 01-12-04 01-14-04

Station Tested 405+30 182+00 390+20 207+50 207+00 406+00 208+00 208+00 211+50 208+25

Section & Test No. 0005-03 0001-05 0005-08 0001-09 0001-15 0005-10 0001-17 0001-19 0001-22 0001-22

Field Moisture 14.0% 16.8% 14.9% 15.0% 13.7% 18.0% 17.2% 17.8% 18.1% 17.7%

Percent Density (QA) 96.8% 95.2% 96.4% 96.3% 99.0% 96.0% 97.7% 99.3% 99.1% 99.3%

Mean

96.7%

97.5%

Standard Deviation

1.13%

1.47%

QC/QA Comparison T-critical

QC/QA Comparison F-critical

QC/QA Comparison Formulas Statistics, QC/QA (Comparison) Statistics, QC (Quality Control/Acceptance)

Pooled Degree Of Freedom, DFp

18

Standard Deviation, Sc

1.189

Pooled Variance S 2p

1.908

Standard Deviation Squared, S 2c

1.414

t-Critical

2.878

96.694

t-Statistic

1.326

Mean, Xc nc n-1c

10 9

Statistics, QA (Quality Assurance/Verification)

t-Statistic < t-Critical

TRUE

f-Critical

6.540

Degree Of Freedom, S 2a/S2c

1.700

Standard Deviation, Sa

1.550

Degree Of Freedom, S2c/S2a

0.588

Standard Deviation Squared, S 2a

2.402

Degree Of Freedom, Larger

1.700

Mean, Xa na n-1a

97.513 10 9

Degree Of Freedom, < f-Critical

TRUE

Verification >= QA / 5

TRUE

Passes All Three Criteria Above

TRUE

QC/QA Comparison Tests Date Tested 11-26-03 12-03-03 12-12-03 12-20-03 12-20-03 12-21-03 01-07-04 01-07-04 01-12-04 01-12-04 01-13-04 01-13-04 01-14-04 01-14-04 01-14-04 01-14-04 01-15-04 01-15-04 01-15-04 01-15-04 01-15-04 01-16-04 01-16-04 01-21-04 01-21-04 01-22-04 01-23-04 01-28-04 02-03-04 02-04-04

Station Tested 201+65 186+00 400+00 405+30 400+00 207+50 182+00 389+50 181+75 182+25 390+00 390+20 207+50 207+00 209+00 208+25 208+40 207+00 406+00 411+00 400+00 208+00 400+00 208+00 208+08 211+50 208+25 320+00 320+00 320+50

Section & Test No. 01-0001 01-0002 05-0001 05-0002 05-0004 01-0003 01-0004 05-0005 0001-06 0001-07 0005-06 0005-07 0001-08 0001-10 0001-11 0001-12 0001-13 0001-14 0005-09 0005-11 0005-12 0001-16 0005-13 0001-18 0001-20 0001-21 0001-23 0003-01 0003-02 0003-04

Field Moisture 14.0% 12.2% 13.7% 14.0% 15.8% 13.4% 16.8% 17.0% 14.7% 14.7% 15.5% 14.9% 15.0% 15.4% 16.9% 17.1% 13.7% 13.7% 18.0% 15.8% 13.7% 17.2% 14.8% 17.8% 17.7% 18.1% 17.7% 15.3% 16.0% 14.9%

Percent Density (QC) 97.8% 96.9% 98.3% 96.9% 95.1% 96.2% 95.3% 95.2% 97.8% 97.4% 95.8% 96.4% 96.3% 96.0% 96.1% 97.2% 98.8% 98.5% 95.5% 96.9% 97.7% 97.5% 98.1% 99.8% 100.2% 98.7% 100.7% 98.2% 97.5% 97.9%

Date Tested

Station Tested

Section & Test No.

Field Moisture

11-26-03 12-03-03 12-12-03 12-20-03 12-20-03 12-21-03 01-07-04 01-07-04 01-12-04 01-14-04

405+30 182+00 390+20 207+50 207+00 406+00 208+00 208+00 211+50 208+25

0005-03 0001-05 0005-08 0001-09 0001-15 0005-10 0001-17 0001-19 0001-22 0001-22

14.0% 16.8% 14.9% 15.0% 13.7% 18.0% 17.2% 17.8% 18.1% 17.7%

Percent Density (QA) 96.8% 95.2% 96.4% 96.3% 99.0% 96.0% 97.7% 99.3% 99.1% 99.3%

01-14-04

208+00

0001-23

19.1%

99.1%

01-15-04

208+25

0001-24

17.7%

99.3%

01-16-04

208+20

0003-01

16.0%

95.8%

01-28-04

320+00

0003-02

15.3%

98.2%

Mean

97.4%

97.7%

Standard Deviation

1.43%

1.47%

QC/QA COMPARISON T-critical

QC/QA Comparison F-critical

QC/QA Comparison Formulas Statistics, QC/QA (Comparison) Statistics, QC (Quality Control/Acceptance)

Pooled Degree Of Freedom, DFp

42

Standard Deviation, Sc

1.451

Pooled Variance S2p

2.176

Standard Deviation Squared, S2c

2.105

t-Critical

2.704

97.359

t-Statistic

0.675

Mean, Xc nc

30

t-Statistic < t-Critical

n-1c

29

f-Critical

3.420

Degree Of Freedom, S2a/S2c

1.109

Statistics, QA (Quality Assurance/Verification)

TRUE

Standard Deviation, Sa

1.528

Degree Of Freedom, S2c/S2a

0.902

Standard Deviation Squared, S2a

2.334

Degree Of Freedom, Larger

1.109

Mean, Xa

97.681

Degree Of Freedom, < f-Critical

TRUE

na

14

Verification >= QA / 5

TRUE

n-1a

13

Passes All Three Criteria Above

TRUE

Experience to Date • The contractors are performing their testing • • •

adequately. The statistical verification process works. The process has been difficult to learn by our inspectors. Large amount of resources required for start-up, training and implementation.

OTHER APPLICATIONS • Cement Content for Soil Cement • Two methods (A&B) One quick

• •

and one more efficient Quick one routinely used Allow contractor to run the test for efficiency

• Base Course Aggregate Gradation

Conclusion • Quality Assurance can be achieved by using the •

• • •

contractor’s quality control in the acceptance decision. The statistical verification approach is one way accomplish this. It’s cost effective only if used on a large number of projects to recover implementation costs. Should Considering Expanding the Use to Not Only Field Testing, But Also Material Testing. Use a More Simplistic Method When You Can

Conclusion

Thickness and Width

Innovation • Doesn’t have to be a new invention • Best practices from other organizations can provide • •

•

benefits In this case, it’s taking what DOTD started and taking it to the next level LTM/DOTD agreement is that innovations are encouraged, but must have DOTD approval DOTD wanted something that could be used on the federal program as well

DOTD and Using Contractor QC for Acceptance • Aggregate gradation at concrete plants • Prior to 1975, DOTD performed tests for Acceptance • Since 1975, contractor (or plant) technician performs, •

with DOTD performing Verification Tests at 1 in 5 frequency Now “tried and true process”

LTM’s Role In Construction • • • • •

55 List B Projects 3 List C Mega Projects Contract Administration CE&I Construction Management

Construction Engineering And Inspection • • • •

Management of construction engineering Construction inspection & field testing Material testing Construction fabrication inspection

QC/QA Comparison Curves QC Tests

95

96

97

98

QA Tests

99

100

95

96

97

98

99

100

QC/QA Comparison Curves QC Tests

95

96

97

98

QA Tests

99

100

95

96

97

98

99

100