FINAL REPORT CONNECTION STRENGTH … strength testing sympaforce geogrids within cornerstone block...

Prepared for:

Luckenhaus Technical Textiles, Inc. 175 Mehler Lane

Martinsville, VA 24112

FINAL REPORT CONNECTION STRENGTH TESTING

SYMPAFORCE GEOGRIDS WITHIN

CORNERSTONE BLOCK UNITS WITH COMPACTED GRAVEL

Prepared by:

4405 International Blvd., Suite B-117 Norcross, GA 30093

Project Number SGI2072

14 February 2004

CAVEAT The reported results apply only to the materials and test conditions used in the laboratory testing program. The results do not necessarily apply to other materials or test conditions. The test results should not be used in engineering analysis unless the test conditions model the anticipated field conditions. The testing was performed in accordance with general engineering testing standards and requirements. This testing report is submitted for the exclusive use of the client to whom it is addressed.

2002 SGI Testing Services

SGI2072/SGI02117-01 02.08.29 1

1. INTRODUCTION

The details of samples submitted for testing to SGI Testing Services, LLC

(SGISM), 4405 International Blvd., Suite B-117, Norcross, Georgia 30093, are as

follows:

Submitted by: Mr. C. Ted Koerner, P.E. Client: Luckenhaus Technical Textiles, Inc. Address: 175 Mehler Lane Martinsville, VA 24112 Materials Tested: Geosynthetic Materials: Sympaforce 30/30, 60/30, and

100/30 geogrids.

Block Units: CornerStone block units

In-Fill Material: AASHTO No. 57 stone (gravel)

2. TEST PROGRAM

The test procedures and results are described in the following appendices:

Appendix A: Summary of Test Procedures Appendix B: Summary of Test Results

Appendix C: Connection Strength Test Results

3. STORAGE AND DISPOSAL OF MATERIALS

Samples will be stored for 30 days from the date of this report and then

discarded unless SGISM is informed otherwise.

* * * * *


SGI2072/SGI02117-01 02.08.29 2

REPORT REVIEW

REPORT PREPARATION BY: TECHNICAL REVIEW BY:

Zehong Yuan, Ph.D., P.E. Robert H. Swan, Jr. Chief Technical Officer President & CEO

APPENDIX A SUMMARY OF TEST PROCEDURES


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SUMMARY OF TEST PROCEDURES Test Method The connection strength tests were performed in accordance with the American Society for Testing and Materials (ASTM) Standard Test Method D 6638, "Determining Connection Strength between GeoSynthetic Reinforcement and Segmental Concrete Units". It is noted that ASTM D 6638 was developed based on National Concrete Masonry Association (NCMA) Test Method SRWU-1, "Determination of Connection Strength between Geosynthetics and Segmental Concrete Units". The connection strength tests were conducted in SGI's pullout testing device that had plan dimensions of 3 ft by 7 ft (0.9 m by 2.1 m) and an overall depth of 20 in. (500 mm). Following guidelines provided by our client, the geogrid specimens used during the connection strength testing were sufficiently large such that the geogrid area within the connection had plan dimensions of approximately 35 in. (890 mm) wide by 12 in. (305 mm) long.

Sample Description and Test Configuration

The testing program consisted of three connection series, each consisting of five connection tests. The configuration of the test specimen for each connection strength test is described, from top to bottom, as follows:

� upper course of CornerStone concrete block units with tamped gravel in unit apertures and between each unit within the course;

� Sympaforce 30/30, 60/30, or 100/30 geogrid; and

� lower course of CornerStone concrete block units with tamped gravel in unit apertures and between each unit within the course.

The cross-section of the connection test configuration is shown in Figure A-1. It is noted that the typical full-size CornerStone block used during this testing program was approximately 18 in. (455 mm) wide, 12 in. (305 mm) long, and 8 in. (200 mm) high, and weighed 76 lbs (35 kg).


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Test Procedure

For each connection test, the test specimen was set up in accordance with the following procedures and tested under the specific conditions as described below:

� A lower course of concrete block units (a full block unit at the center and a half block unit on each side) was placed in the lower half of the pullout box. The concrete block units were oriented so that the back of the concrete block units were against the front wall of the pullout box. Fresh specimens of the gravel were compacted into the lower unit apertures and areas between the lower units by hand tamping to a relatively dense state under dry conditions;

� For each test, a fresh geogrid specimen was trimmed from the bulk sample and placed on the top of the lower block units. The front end of the geogrid was cast in a low temperature-curing epoxy to form the test specimen clamp;

� The upper course of concrete block units (two full blocks) was placed directly on top of the geogrid. The concrete block units were oriented so that the back of the concrete block units were against the front wall of the pullout box. Additional fresh specimens of the gravel were compacted into the upper unit apertures and areas between the upper units by hand tamping to a relatively dense state under dry conditions;

� A specific normal stress was applied to the top of the concrete block units/gravel/geogrid wall system using a loading system consisting of three hydraulic cylinders;

� After application of the normal stress, each geogrid specimen was immediately subjected to a tensile strain rate of 10 percent per minute which was calculated based on the exposed length of the geogrid specimen (i.e., the length between the back of the concrete units and the edge of the epoxy clamp closest to the pullout box). Pulling out of the geogrid specimen was continued until a constant or decreasing pullout load was recorded; and

� Each geogrid specimen used during this study was tested in the machine direction.


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Test Data Presentation

For each connection strength test, abrasion and rupture of the geogrid specimen were observed to occur after the completion of the test. The test data were plotted as connection force versus horizontal displacement, and are presented in Appendix C. Connection force is defined as connection load divided by the initial width of the geogrid specimen. Connection strength at 0.75-in. (19-mm) horizontal displacement was defined as the connection force at this value of displacement. Peak connection strength was defined as the peak value of connection force. The connection strength at 0.75-in. (19-mm) horizontal displacement and the peak connection strength derived from the plotted tests results are summarized in Appendix B, and also presented graphically in Appendix C. A best-fit straight line was drawn through the two sets of test data points to obtain a mathematical expression for both the peak and 0.75-in. connection strengths. The mathematical expressions for both the peak and 0.75-in. connection strengths are also presented in the figures in Appendix C.


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(NOTE: Not to Scale)

Figure A-1 Schematic Diagram of Test Specimen Cross-Section

Geogrid

Normal Load

Epoxy Clamp System

Front of Pullout Box

Cushion Layer

Loading Plates

Block Facing

Gravel

Gravel

Concrete Keys

Rigid Spacer

APPENDIX B

SUMMARY OF TEST RESULTS

SGI2072/SGI04022-01 04.02.14

TABLE 1 SUMMARY OF CONNECTION STRENGTH TEST RESULTS

LUCKENHAUS TECHNICAL TEXTILES, INC.

Test Series

Number(1)

Test Specimen Description Test Specimen

Width (in)

Test Normal Stress(2)

(psi)

Test Normal

Load (lb/ft)

ApproximateNo. of Blocks

(-)

Approximate Wall

Height (ft)

0.75-in. Connection

Strength (lbs/ft)

Peak Connection

Strength (lbs/ft)

35.0 4.0 575 8 5.0 479 567 35.0 8.0 1150 15 10.0 518 611 35.0 8.0 1150 15 10.0 543 593 35.0 8.0 1150 15 10.0 540 649

1 Sympaforce 30/30 geogrid in machine direction within CornerStone block units with compacted

AASHTO #57 stone

35.0 12.0 1725 23 15.0 654 750 35.0 12.0 1725 23 15.0 1114 1459 35.0 20.0 2875 38 25.0 1355 1652 35.0 20.0 2875 38 25.0 1346 1639 35.0 20.0 2875 38 25.0 1347 1660


AASHTO #57 stone

35.0 28.0 4025 53 35.0 1549 1909 35.0 20.0 2875 38 25.0 1467 2396 35.0 33.9 4888 64 42.5 2158 2916 35.0 33.9 4888 64 42.5 2183 2883 35.0 33.9 4888 64 42.5 1933 2863


AASHTO #57 stone

35.0 47.9 6900 90 60.0 2425 3276

Note: (1) For each test, the geogrid specimen within the connection had a total length of approximately 12 in.

(2) The normal load was applied to top of the block/gravel/geogrid/block wall system through a loading system consisting of three hydraulic cylinders. (3) For each test, abrasion and rupture of geogrid ribs were observed after the completion of the test.

APPENDIX C

CONNECTION STRENGTH TEST DATA

TEST SERIES NO. 1: Sympaforce 30/30 geogrid in machine direction within CornerStone block units with AASHTO #57 stone (gravel

Test Test Test Equivalent Approx. Approx. 0.75-in. PeakNo. Specimen Normal Normal No. of Strength Strength

Width Stress Load Blocks Height(in.) (psi) (lb/ft) (ft) (lb/ft) (lb/ft)

1A 35.0 4.0 575 8 5.0 479 5671B 35.0 8.0 1150 15 10.0 518 611 T 0.75-in. = 370 + (N) tan ( 9 )1C 35.0 8.0 1150 15 10.0 543 5931D 35.0 8.0 1150 15 10.0 540 649 T peak = 450 + (N) tan ( 9 )1E 35.0 12.0 1725 23 15.0 654 750

NOTES:Dimensions of CornerStone Block: 18 in. wide by 12 in. long and 8 in. high.Weight of a full-size CornerStone block: 76 lbs.Failure Mode of Geogrid: abrasion and rupture of the geogrid ribs.

DATE TESTED: 19 to 21 January 2004FIGURE NO. C-1PROJECT NO. SGI2072DOCUMENT NO. SGI04022FILE NO.

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FINAL REPORT CONNECTION STRENGTH … strength testing sympaforce geogrids within cornerstone block...

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