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Publication Number: FHWA-HRT-11-027
Date: JANUARY 2011

 

Geosynthetic Reinforced Soil Integrated Bridge System Synthesis Report

APPENDIX B. PREDICTION DATA FOR ANALYTICAL EQUATIONS

B.1 INTRODUCTION

Seventeen tests were used to validate the soil-geosynthetic capacity and required reinforcement strength equations. The complete set of data from these tests is presented in table 7.

Table 7. Prediction data for large-scale tests.

Test

Reference No.

σc
(lb/ft2)

Sv(inch)

Tf (lb/ft)

dmax (inch)

c (lb/ft2)

φ
(degrees)

H (ft)

qrupture (lb/ft2)

γ
(lb/ft3)

GSGC 1

10

710

None

1.3

1,462

50

6.5

153

GSGC 2

10

710

8

4,800

1.3

1,462

50

6.5

56,403

153

GSGC 3

10

710

16

9,600

1.3

1,462

50

6.5

36,558

153

GSGC 4

10

710

16

4,800

1.3

1,462

50

6.5

27,157

153

GSGC 5

10

0

8

4,800

1.3

1,462

50

6.5

39,691

153

Elton and Patawaran 1

23

0

6

620

0.5

576

40

5

4,805

121

Elton and Patawaran 2

23

0

12

620

0.5

576

40

5

2,695

121

Elton and Patawaran 3

23

0

6

960

0.5

576

40

5

6,392

121

Elton and Patawaran 4

23

0

6

1,025

0.5

576

40

5

6,100

121

Elton and Patawaran 5

23

0

6

1,300

0.5

576

40

5

8,398

121

Elton and Patawaran 6

23

0

6

1,400

0.5

576

40

5

8,293

121

Elton and Patawaran 7

23

0

6

1,700

0.5

576

40

5

9,589

121

NCHRP 1

7

0

8

1,400

1

418

37.3

15

7,312

117

NCHRP 2

7

0

8

4,800

1

418

37.3

15

17,757

117

Defiance 1

24

0

8a

2,400

0.5

0

48.7

6.4

11,320

110

Defiance 2

24

0

8a

4,800

0.5

0

48.7

6.4

21,412

110

Vegas
Mini Pier

20

0

6a

2,400

1

576

40

8

20,890

121

B.2 SOIL-GEOSYNTHETIC CAPACITY EQUATION

The load-carrying capacity of a GRS wall and abutment (qult,an,c) can be evaluated using an analytical formula (equation 3). For this equation, the calculated capacity matches well with the measured capacity from large-scale tests (see figure 12). The numerical results of this comparison are presented in table 8. Note that for long-term design, cohesion (c) and confining stress (σc) are assumed to equal zero and should not be accounted for.

Table 8. Soil-geosynthetic capacity equation validation results.

Test

Reference No.

qmeasured(lb/ft2)

qcalc
(lb/ft2)

GSGC 1

10

16,085

12,680

GSGC 2

10

56,403

51,181

GSGC 3

10

36,558

39,545

GSGC 4

10

27,157

26,113

GSGC 5

10

39,691

46,522

Elton and Patawaran 1

23

4,805

5,327

Elton and Patawaran 2

23

2,695

3,175

Elton and Patawaran 3

23

6,392

6,915

Elton and Patawaran 4

23

6,100

7,228

Elton and Patawaran 5

23

8,398

8,502

Elton and Patawaran 6

23

8,293

8,816

Elton and Patawaran 7

23

9,589

10,403

NCHRP 1

7

8,356

7,291

NCHRP 2

7

17,757

20,347

Defiance 1

24

13,370

11,322

Defiance 2

24

25,068

20,180

Vegas Mini Pier

20

20,890

18,258

B.3 REQUIRED REINFORCEMENT STRENGTH EQUATION

For the required reinforcement strength equation (equation 13), the calculated strength matches well with the actual strength at rupture from large-scale tests (see figure 16). The biggest differences occur with some of the GSCS tests, which had a uniform confining pressure applied.(10) This confining stress will likely not be present in an actual GRS-IBS application. The numerical results of this comparison are presented in table 9. Note that for long-term design, the cohesion (c) and confining stress (σc) is assumed to equal zero and should not be accounted for.

Table 9. Required reinforcement strength equation validation results

Test

Reference No.

Tactual
(lb/ft)

Tcalc
(lb/ft)

GSGC 2

10

4,800

5,483

GSGC 3

10

9,600

8,633

GSGC 4

10

4,800

5,274

GSGC 5

10

4,800

4,069

Elton and Patawaran 1

23

620

632

Elton and Patawaran 2

23

620

712

Elton and Patawaran 3

23

960

975

Elton and Patawaran 4

23

1,025

912

Elton and Patawaran 5

23

1,300

1,408

Elton and Patawaran 6

23

1,400

1,385

Elton and Patawaran 7

23

1,700

1,665

NCHRP 1

7

1,400

1,902

NCHRP 2

7

4,800

4,587

Defiance 1

24

2,400

2,857

Defiance 2

24

4,800

5,254

Vegas Mini Pier

20

2,400

2,944

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