Roadbed Soil Resilient Modulus

The resilient modulus is a measure of the ability of a soil or granular base to resist permanent deformation under repeated loading. Many soils are stress-dependent. As the stress level increases, these soils will behave in a nonlinear fashion. Fine-grain soils tend to be stress-softening, whereas granular soils tend to be stress-hardening. Laboratory procedures for determining resilient modulus have been published by AASHTO as test method T307, or NCHRP as test method 1-38A. A typical setup for the laboratory test is shown in Fig. 3.9. The stress due to the repeated load applied through the load actuator is the deviator stress and is intended to duplicate the effect of loads passing over a section of pavement. The confining stress within the chamber is intended to duplicate the confinement of the soil within the subgrade. A typical load-response curve is shown in Fig. 3.10. As shown, the resilient modulus (MR) is the ratio of deviator stress to strain in the elastic range.

The laboratory procedures for determining resilient modulus are complex and timeconsuming. Many equations have been developed relating the resilient modulus to soil properties that are more easily determined. One such property is the California

TABLE 3.11 Axle Load Equivalency Factors for Rigid Pavements, Tandem Axles, and pt of 2.0

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0006	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005
6	27	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
8	36	0.006	0.006	0.005	0.005	0.005	0.005	0.005	0.005	0.005
10	44	0.014	0.013	0.013	0.012	0.012	0.012	0.012	0.012	0.012
12	53	0.028	0.026	0.026	0.025	0.025	0.025	0.025	0.025	0.025
14	62	0.051	0.049	0.048	0.047	0.047	0.047	0.047	0.047	0.047
16	71	0.087	0.084	0.082	0.081	0.081	0.080	0.080	0.080	0.080
18	80	0.141	0.136	0.133	0.132	0.131	0.131	0.131	0.131	0.131
20	89	0.216	0.210	0.206	0.204	0.203	0.203	0.203	0.203	0.203
22	98	0.319	0.313	0.307	0.305	0.304	0.303	0.303	0.303	0.303
24	107	0.454	0.449	0.444	0.441	0.440	0.439	0.439	0.439	0.439
26	116	0.629	0.626	0.622	0.620	0.618	0.618	0.618	0.618	0.618
28	125	0.852	0.851	0.850	0.850	0.850	0.849	0.849	0.849	0.849
30	133	1.13	1.13	1.14	1.14	1.14	1.14	1.14	1.14	1.14
32	142	1.48	1.48	1.49	1.50	1.51	1.51	1.51	1.51	1.51
34	151	1.90	1.90	1.93	1.95	1.96	1.97	1.97	1.97	1.97
36	160	2.42	2.41	2.45	2.49	2.51	2.52	2.53	2.53	2.53
38	169	3.04	3.02	3.07	3.13	3.17	3.19	3.20	3.20	3.21
40	178	3.79	3.74	3.80	3.89	3.95	3.98	4.00	4.01	4.01
42	187	4.67	4.59	4.66	4.78	4.87	4.93	4.95	4.97	4.97
44	196	5.72	5.59	5.67	5.82	5.95	6.03	6.07	6.09	6.10
46	205	6.94	6.76	6.83	7.02	7.20	7.31	7.37	7.41	7.43
48	214	8.36	8.12	8.17	8.40	8.63	8.79	8.88	8.93	8.96
50	222	10.00	9.69	9.72	9.98	10.27	10.49	10.62	10.69	10.73
52	231	11.9	11.5	11.5	11.8	12.1	12.4	12.6	12.7	12.8
54	240	14.0	13.5	13.5	13.8	14.2	14.6	14.9	15.0	15.1
56	249	16.5	15.9	15.8	16.1	16.6	17.1	17.4	17.6	17.7
58	258	19.3	18.5	18.4	18.7	19.3	19.8	20.3	20.5	20.7
60	267	22.4	21.5	21.3	21.6	22.3	22.9	23.5	23.8	24.0
62	276	25.9	24.9	24.6	24.9	25.6	26.4	27.0	27.5	27.7
64	285	29.9	28.6	28.2	28.5	29.3	30.2	31.0	31.6	31.9
66	294	34.3	32.8	32.3	32.6	33.4	34.4	35.4	36.1	36.5
68	302	39.2	37.5	36.8	37.1	37.9	39.1	40.2	41.1	41.6
70	311	44.6	42.7	41.9	42.1	42.9	44.2	45.5	46.6	47.3
72	320	50.6	48.4	47.5	47.6	48.5	49.9	51.4	52.6	53.5
74	329	57.3	54.7	53.6	53.6	54.6	56.1	57.7	59.2	60.3
76	338	64.6	61.7	60.4	60.3	61.2	62.8	64.7	66.4	67.7
78	347	72.5	69.3	67.8	67.7	68.6	70.2	72.3	74.3	75.8
80	356	81.3	77.6	75.9	75.7	76.6	78.3	80.6	82.8	84.7
82	365	90.9	86.7	84.7	84.4	85.3	87.1	89.6	92.1	94.2
84	374	101.	97.	94.	94.	95.	97.	99.	102.	105.
86	383	113.	107.	105.	104.	105.	107.	110.	113.	116.
88	391	125.	119.	116.	116.	116.	118.	121.	125.	128.
90	400	138.	132.	129.	128.	129.	131.	134.	137.	141.

Conversion: 1 in = 25.4 mm.

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003
6	27	0.0010	0.0009	0.0009	0.0009	0.0009	0.0009	0.0009	0.0009	0.0009
8	36	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
10	44	0.005	0.005	0.005	0.005	0.005	0.005	0.005	0.005	0.005
12	53	0.010	0.010	0.009	0.009	0.009	0.009	0.009	0.009	0.009
14	62	0.018	0.017	0.017	0.016	0.016	0.016	0.016	0.016	0.016
16	71	0.030	0.029	0.028	0.027	0.027	0.027	0.027	0.027	0.027
18	80	0.047	0.045	0.044	0.044	0.043	0.043	0.043	0.043	0.043
20	89	0.072	0.069	0.067	0.066	0.066	0.066	0.066	0.066	0.066
22	98	0.105	0.101	0.099	0.098	0.097	0.097	0.097	0.097	0.097
24	107	0.149	0.144	0.141	0.139	0.139	0.138	0.138	0.138	0.138
26	116	0.205	0.199	0.195	0.194	0.193	0.192	0.192	0.192	0.192
28	125	0.276	0.270	0.265	0.263	0.262	0.262	0.262	0.262	0.261
30	133	0.364	0.359	0.354	0.351	0.350	0.349	0.349	0.349	0.349
32	142	0.472	0.468	0.463	0.460	0.459	0.458	0.458	0.458	0.458
34	151	0.603	0.600	0.596	0.594	0.593	0.592	0.592	0.592	0.592
36	160	0.759	0.758	0.757	0.756	0.755	0.755	0.755	0.755	0.755
38	169	0.946	0.947	0.949	0.950	0.951	0.951	0.951	0.951	0.951
40	178	1.17	1.17	1.18	1.18	1.18	1.18	1.18	1.18	1.19
42	187	1.42	1.43	1.44	1.45	1.46	1.46	1.46	1.46	1.46
44	196	1.73	1.73	1.75	1.77	1.78	1.78	1.79	1.79	1.79
46	205	2.08	2.07	2.10	2.13	2.15	2.16	2.16	2.16	2.17
48	214	2.48	2.47	2.51	2.55	2.58	2.59	2.60	2.60	2.61
50	222	2.95	2.92	2.97	3.03	3.07	3.09	3.10	3.11	3.11
52	231	3.48	3.44	3.50	3.58	3.63	3.66	3.68	3.69	3.69
54	240	4.09	4.03	4.09	4.20	4.27	4.31	4.33	4.35	4.35
56	249	4.78	4.69	4.76	4.89	4.99	5.05	5.08	5.09	5.10
58	258	5.57	5.44	5.51	5.66	5.79	5.87	5.91	5.94	5.95
60	267	6.45	6.29	6.35	6.53	6.69	6.79	6.85	6.88	6.90
62	276	7.43	7.23	7.28	7.49	7.69	7.82	7.90	7.94	7.97
64	285	8.54	8.28	8.32	8.55	8.80	8.97	9.07	9.13	9.16
66	294	9.76	9.46	9.48	9.73	10.02	10.24	10.37	10.44	10.48
68	302	11.1	10.8	10.8	11.0	11.4	11.6	11.8	11.9	12.0
70	311	12.6	12.2	12.2	12.5	12.8	13.2	13.4	13.5	13.6
72	320	14.3	13.8	13.7	14.0	14.5	14.9	15.1	15.3	15.4
74	329	16.1	15.5	15.4	15.7	16.2	16.7	17.0	17.2	17.3
76	338	18.2	17.5	17.3	17.6	18.2	18.7	19.1	19.3	19.5
78	347	20.4	19.6	19.4	19.7	20.3	20.9	21.4	21.7	21.8
80	356	22.8	21.9	21.6	21.9	22.6	23.3	23.8	24.2	24.4
82	365	25.4	24.4	24.1	24.4	25.0	25.8	26.5	26.9	27.2
84	374	28.3	27.1	26.7	27.0	27.7	28.6	29.4	29.9	30.2
86	383	31.4	30.1	29.6	29.9	30.7	31.6	32.5	33.1	33.5
88	391	34.8	33.3	32.8	33.0	33.8	34.8	35.8	36.6	37.1
90	400	38.5	36.8	36.2	36.4	37.2	38.3	39.4	40.3	40.9

Conversion: 1 in = 25.4 mm.

TABLE 3.13 Axle Load Equivalency Factors for Rigid Pavements, Single Axles, and pt of 2.5

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0002	0.0002	0.0002	0.0002	0.0002	0.0002	0.0002	0.0002	0.0002
4	18	0.003	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
6	27	0.012	0.011	0.010	0.010	0.010	0.010	0.010	0.010	0.010
8	36	0.039	0.035	0.033	0.032	0.032	0.032	0.032	0.032	0.032
10	44	0.097	0.089	0.084	0.082	0.081	0.080	0.080	0.080	0.080
12	53	0.203	0.189	0.181	0.176	0.175	0.174	0.174	0.173	0.173
14	62	0.376	0.360	0.347	0.341	0.338	0.337	0.336	0.336	0.336
16	71	0.634	0.623	0.610	0.604	0.601	0.599	0.599	0.599	0.598
18	80	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
20	89	1.51	1.52	1.55	1.57	1.58	1.58	1.59	1.59	1.59
22	98	2.21	2.20	2.28	2.34	2.38	2.40	2.41	2.41	2.41
24	107	3.16	3.10	3.22	3.36	3.45	3.50	3.53	3.54	3.55
26	116	4.41	4.26	4.42	4.67	4.85	4.95	5.01	5.04	5.05
28	125	6.05	5.76	5.92	6.29	6.61	6.81	6.92	6.98	7.01
30	133	8.16	7.67	7.79	8.28	8.79	9.14	9.35	9.46	9.52
32	142	10.8	10.1	10.1	10.7	11.4	12.0	12.3	12.6	12.7
34	151	14.1	13.0	12.9	13.6	14.6	15.4	16.0	16.4	16.5
36	160	18.2	16.7	16.4	17.1	18.3	19.5	20.4	21.0	21.3
38	169	23.1	21.1	20.6	21.3	22.7	24.3	25.6	26.4	27.0
40	178	29.1	26.5	25.7	26.3	27.9	29.9	31.6	32.9	33.7
42	187	36.2	32.9	31.7	32.2	34.0	36.3	38.7	40.4	41.6
44	196	44.6	40.4	38.8	39.2	41.0	43.8	46.7	49.1	50.8
46	205	54.5	49.3	47.1	47.3	49.2	52.3	55.9	59.0	61.4
48	214	66.1	59.7	56.9	56.8	58.7	62.1	66.3	70.3	73.4
50	222	79.4	71.7	68.2	67.8	69.6	73.3	78.1	83.0	87.1

Conversion: 1 in = 25.4 mm.

Source: Guide for Design of Pavement Structures, American Association of State Highway and

Transportation Officials, Washington, D. C., 1993, with permission.

Bearing Ratio (CBR). Common equations using CBR to calculate resilient modulus values include the following:

E (lb/in2) = 1500 CBR (Shell Oil Co.)

E (lb/in2) = 5409 CBR0 711 (U. S. Army Waterway Experiment Station)

E (lb/in2) = 2550 CBR0 64 (Transport and Road Research Laboratory, England)

(See “Pavement Deflection Analysis,” FHWA Report HI-94-021, NHI, February 1994.) More detailed equations have been developed by correlating laboratory results with fundamental soil properties. R. F. Carmichael III and E. Stuart (“Predicting Resilient Modulus: A Study to Determine the Mechanical Properties of Subgrade Soils,” Transportation Research Record 1043, Transportation Research Board, National Research Council, Washington, D. C., 1985) developed the following models for the U. S. Forest Service:

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0006	0.0006	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005
6	27	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
8	36	0.007	0.006	0.006	0.005	0.005	0.005	0.005	0.005	0.005
10	44	0.015	0.014	0.013	0.013	0.012	0.012	0.012	0.012	0.012
12	53	0.031	0.028	0.026	0.026	0.025	0.025	0.025	0.025	0.025
14	62	0.057	0.052	0.049	0.048	0.047	0.047	0.047	0.047	0.047
16	71	0.097	0.089	0.084	0.082	0.081	0.081	0.080	0.080	0.080
18	80	0.155	0.143	0.136	0.133	0.132	0.131	0.131	0.131	0.131
20	89	0.234	0.220	0.211	0.206	0.204	0.203	0.203	0.203	0.203
22	98	0.340	0.325	0.313	0.308	0.305	0.304	0.303	0.303	0.303
24	107	0.475	0.462	0.450	0.444	0.441	0.440	0.439	0.439	0.439
26	116	0.644	0.637	0.627	0.622	0.620	0.619	0.618	0.618	0.618
28	125	0.855	0.854	0.852	0.850	0.850	0.850	0.849	0.849	0.849
30	133	1.11	1.12	1.13	1.14	1.14	1.14	1.14	1.14	1.14
32	142	1.43	1.44	1.47	1.49	1.50	1.51	1.51	1.51	1.51
34	151	1.82	1.82	1.87	1.92	1.95	1.96	1.97	1.97	1.97
36	160	2.29	2.27	2.35	2.43	2.48	2.51	2.52	2.52	2.53
38	169	2.85	2.80	2.91	3.03	3.12	3.16	3.18	3.20	3.20
40	178	3.52	3.42	3.55	3.74	3.87	3.94	3.98	4.00	4.01
42	187	4.32	4.16	4.30	4.55	4.74	4.86	4.91	4.95	4.96
44	196	5.26	5.01	5.16	5.48	5.75	5.92	6.01	6.06	6.09
46	205	6.36	6.01	6.14	6.53	6.90	7.14	7.28	7.36	7.40
48	214	7.64	7.16	7.27	7.73	8.21	8.55	8.75	8.86	8.92
50	222	9.11	8.50	8.55	9.07	9.68	10.14	10.42	10.58	10.66
52	231	10.8	10.0	10.0	10.6	11.3	11.9	12.3	12.5	12.7
54	240	12.8	11.8	11.7	12.3	13.2	13.9	14.5	14.8	14.9
56	249	15.0	13.8	13.6	14.2	15.2	16.2	16.8	17.3	17.5
58	258	17.5	16.0	15.7	16.3	17.5	18.6	19.5	20.1	20.4
60	267	20.3	18.5	18.1	18.7	20.0	21.4	22.5	23.2	23.6
62	276	23.5	21.4	20.8	21.4	22.8	24.4	25.7	26.7	27.3
64	285	27.0	24.6	23.8	24.4	25.8	27.7	29.3	30.5	31.3
66	294	31.0	28.1	27.1	27.6	29.2	31.3	33.2	34.7	35.7
68	302	35.4	32.1	30.9	31.3	32.9	35.2	37.5	39.3	40.5
70	311	40.3	36.5	35.0	35.3	37.0	39.5	42.1	44.3	45.9
72	320	45.7	41.4	39.6	39.8	41.5	44.2	47.2	49.8	51.7
74	329	51.7	46.7	44.6	44.7	46.4	49.3	52.7	55.7	58.0
76	338	58.3	52.6	50.2	50.1	51.8	54.9	58.6	62.1	64.8
78	347	65.5	59.1	56.3	56.1	57.7	60.9	65.0	69.0	72.3
80	356	73.4	66.2	62.9	62.5	64.2	67.5	71.9	76.4	80.2
82	365	82.0	73.9	70.2	69.6	71.2	74.7	79.4	84.4	88.8
84	374	91.4	82.4	78.1	77.3	78.9	82.4	87.4	93.0	98.1
86	383	102.	92.	87.	86.	87.	91.	96.	102.	108.
88	391	113.	102.	96.	95.	96.	100.	105.	112.	119.
90	400	125.	112.	106.	105.	106.	110.	115.	123.	130.

Conversion: 1 in = 25.4 mm.

TABLE 3.15 Axle Load Equivalency Factors for Rigid Pavements, Triple Axles, and pt of 2.5

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003
6	27	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001
8	36	0.003	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
10	44	0.006	0.005	0.005	0.005	0.005	0.005	0.005	0.005	0.005
12	53	0.011	0.010	0.010	0.009	0.009	0.009	0.009	0.009	0.009
14	62	0.020	0.018	0.017	0.017	0.016	0.016	0.016	0.016	0.016
16	71	0.033	0.030	0.029	0.028	0.027	0.027	0.027	0.027	0.027
18	80	0.053	0.048	0.045	0.044	0.044	0.043	0.043	0.043	0.043
20	89	0.080	0.073	0.069	0.067	0.066	0.066	0.066	0.066	0.066
22	98	0.116	0.107	0.101	0.099	0.098	0.097	0.097	0.097	0.097
24	107	0.163	0.151	0.144	0.141	0.139	0.139	0.138	0.138	0.138
26	116	0.222	0.209	0.200	0.195	0.194	0.193	0.192	0.192	0.192
28	125	0.295	0.281	0.271	0.265	0.263	0.262	0.262	0.262	0.262
30	133	0.384	0.371	0.359	0.354	0.351	0.350	0.349	0.349	0.349
32	142	0.490	0.480	0.468	0.463	0.460	0.459	0.458	0.458	0.458
34	151	0.616	0.609	0.601	0.596	0.594	0.593	0.592	0.592	0.592
36	160	0.765	0.762	0.759	0.757	0.756	0.755	0.755	0.755	0.755
38	169	0.939	0.941	0.946	0.948	0.950	0.951	0.951	0.951	0.951
40	178	1.14	1.15	1.16	1.17	1.18	1.18	1.18	1.18	1.18
42	187	1.38	1.38	1.41	1.44	1.45	1.46	1.46	1.46	1.46
44	196	1.65	1.65	1.70	1.74	1.77	1.78	1.78	1.78	1.79
46	205	1.97	1.96	2.03	2.09	2.13	2.15	2.16	2.16	2.16
48	214	2.34	2.31	2.40	2.49	2.55	2.58	2.59	2.60	2.60
50	222	2.76	2.71	2.81	2.94	3.02	3.07	3.09	3.10	3.11
52	231	3.24	3.15	3.27	3.44	3.56	3.62	3.66	3.68	3.68
54	240	3.79	3.66	3.79	4.00	4.16	4.26	4.30	4.33	4.34
56	249	4.41	4.23	4.37	4.63	4.84	4.97	5.03	5.07	5.09
58	258	5.12	4.87	5.00	5.32	5.59	5.79	5.85	5.90	5.93
60	267	5.91	5.59	5.71	6.08	6.42	6.64	6.77	6.84	6.87
62	276	6.80	6.39	6.50	6.91	7.33	7.62	7.79	7.88	7.93
64	285	7.79	7.29	7.37	7.82	8.33	8.70	8.92	9.04	9.11
66	294	8.90	8.28	8.33	8.83	9.42	9.88	10.17	10.33	10.42
68	302	10.1	9.4	9.4	9.9	10.6	11.2	11.5	11.7	11.9
70	311	11.5	10.6	10.6	11.1	11.9	12.6	13.0	13.3	13.5
72	320	13.0	12.0	11.8	12.4	13.3	14.1	14.7	15.0	15.2
74	329	14.6	13.5	13.2	13.8	14.8	15.8	16.5	16.9	17.1
76	338	16.5	15.1	14.8	15.4	16.5	17.6	18.4	18.9	19.2
78	347	18.5	16.9	16.5	17.1	18.2	19.5	20.5	21.1	21.5
80	356	20.6	18.8	18.3	18.9	20.2	21.6	22.7	23.5	24.0
82	365	23.0	21.0	20.3	20.9	22.2	23.8	25.2	26.1	26.7
84	374	25.6	23.3	22.5	23.1	24.5	26.2	27.8	28.9	29.6
86	383	28.4	25.8	24.9	25.4	26.9	28.8	30.5	31.9	32.8
88	391	31.5	28.6	27.5	27.9	29.4	31.5	33.5	35.1	36.1
90	400	34.8	31.5	30.3	30.7	32.2	34.4	36.7	38.5	39.8

Conversion: 1 in = 25.4 mm.

Подпись:
Cohesive soils:

MR = 37.431 — 0.4566(PI) — 0.6179(%W) — 0.1424(S200) +

Подпись: (3.5) 0.1791(CS) — 0.3248(DS) + 36.422(CH) + 17.097(MH)

Подпись: where MR PI %W S200 CS DS CH MH resilient modulus, kips/in2 plasticity index percentage water

percentage passing the no. 200 sieve confining stress, lb/in2 deviator stress, lb/in2

1 for CH soil (Unified Soil Classification, Art. 8.3.2)

0 otherwise

1 for MH soil (Unified Soil Classification)

0 otherwise

TABLE 3.17 Axle Load Equivalency Factors for Rigid Pavements, Tandem Axles, andpt of 3.0

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0007	0.0006	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005	0.0005
6	27	0.003	0.002	0.002	0.002	0.002	0.002	0.002	0.002	0.002
8	36	0.008	0.006	0.006	0.006	0.005	0.005	0.005	0.005	0.005
10	44	0.018	0.015	0.013	0.013	0.013	0.012	0.012	0.012	0.012
12	53	0.036	0.030	0.027	0.026	0.026	0.025	0.025	0.025	0.025
14	62	0.066	0.056	0.050	0.048	0.047	0.047	0.047	0.047	0.047
16	71	0.111	0.095	0.087	0.083	0.081	0.081	0.081	0.080	0.080
18	80	0.174	0.153	0.140	0.135	0.132	0.131	0.131	0.131	0.131
20	89	0.260	0.234	0.217	0.209	0.205	0.204	0.203	0.203	0.203
22	98	0.368	0.341	0.321	0.311	0.307	0.305	0.304	0.303	0.303
24	107	0.502	0.479	0.458	0.447	0.443	0.440	0.440	0.439	0.439
26	116	0.664	0.651	0.634	0.625	0.621	0.619	0.618	0.618	0.618
28	125	0.859	0.857	0.853	0.851	0.850	0.850	0.850	0.849	0.849
30	133	1.09	1.10	1.12	1.13	1.14	1.14	1.14	1.14	1.14
32	142	1.38	1.38	1.44	1.47	1.49	1.50	1.51	1.51	1.51
34	151	1.72	1.71	1.80	1.88	1.93	1.95	1.96	1.97	1.97
36	160	2.13	2.10	2.23	2.36	2.45	2.49	2.51	2.52	2.52
38	169	2.62	2.54	2.71	2.92	3.06	3.13	3.17	3.19	3.20
40	178	3.21	3.05	3.26	3.55	3.76	3.89	3.95	3.98	4.00
42	187	3.90	3.65	3.87	4.26	4.58	4.77	4.87	4.92	4.95
44	196	4.72	4.35	4.57	5.06	5.50	5.78	5.94	6.02	6.06
46	205	5.68	5.16	5.36	5.95	6.54	6.94	7.17	7.29	7.36
48	214	6.80	6.10	6.25	6.93	7.69	8.24	8.57	8.76	8.86
50	222	8.09	7.17	7.26	8.03	8.96	9.70	10.17	10.43	10.58
52	231	9.57	8.41	8.40	9.24	10.36	11.32	11.96	12.33	12.54
54	240	1.13	9.8	9.7	10.6	11.9	13.1	14.0	14.5	14.8
56	249	13.2	11.4	11.2	12.1	13.6	15.1	16.2	16.9	17.3
58	258	15.4	13.2	12.8	13.7	15.4	17.2	18.6	19.5	20.1
60	267	17.9	15.3	14.7	15.6	17.4	19.5	21.3	22.5	23.2
62	276	20.6	17.6	16.8	17.6	19.6	22.0	24.1	25.7	26.6
64	285	23.7	20.2	19.1	19.9	22.0	24.7	27.3	29.2	30.4
66	294	27.2	23.1	21.7	22.4	24.6	27.6	30.6	33.0	34.6
68	302	31.1	26.3	24.6	25.2	27.4	30.8	34.3	37.1	39.2
70	311	35.4	29.8	27.8	28.2	30.6	34.2	38.2	41.6	44.1
72	320	40.1	33.8	31.3	31.6	34.0	37.9	42.3	46.4	49.4
74	329	45.3	38.1	35.2	35.4	37.7	41.8	46.8	51.5	55.2
76	338	51.1	42.9	39.5	39.5	41.8	46.1	51.5	56.9	61.3
78	347	57.4	48.2	44.3	44.0	46.3	50.7	56.6	62.7	67.9
80	356	64.3	53.9	49.4	48.9	51.1	55.8	62.1	68.9	74.9
82	365	71.8	60.2	55.1	54.3	56.5	61.2	67.9	75.5	82.4
84	374	80.0	67.0	61.2	60.2	62.2	67.0	74.2	82.4	90.3
86	383	89.0	74.5	67.9	66.5	68.5	73.4	80.8	89.8	98.7
88	391	98.7	82.5	75.2	73.5	75.3	80.2	88.0	97.7	107.5
90	400	109.	91.	83.	81.	83.	88.	96.	106.	117

Conversion: 1 in = 25.4 mm.

Axle load				Slab thickness D, in
kips	kN	6	7	8	9	10	11	12	13	14
2	9	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
4	18	0.0004	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003	0.0003
6	27	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001
8	36	0.003	0.003	0.002	0.002	0.002	0.002	0.002	0.002	0.002
10	44	0.007	0.006	0.005	0.005	0.005	0.005	0.005	0.005	0.005
12	53	0.013	0.011	0.010	0.009	0.009	0.009	0.009	0.009	0.009
14	62	0.023	0.020	0.018	0.017	0.017	0.016	0.016	0.016	0.016
16	71	0.039	0.033	0.030	0.028	0.028	0.027	0.027	0.027	0.027
18	80	0.061	0.052	0.047	0.045	0.044	0.044	0.043	0.043	0.043
20	89	0.091	0.078	0.071	0.068	0.067	0.066	0.066	0.066	0.066
22	98	0.132	0.114	0.104	0.100	0.098	0.097	0.097	0.097	0.097
24	107	0.183	0.161	0.148	0.143	0.140	0.139	0.139	0.138	0.138
26	116	0.246	0.221	0.205	0.198	0.195	0.193	0.193	0.192	0.192
28	125	0.322	0.296	0.277	0.268	0.265	0.263	0.262	0.262	0.262
30	133	0.411	0.387	0.367	0.357	0.353	0.351	0.350	0.349	0.349
32	142	0.515	0.495	0.476	0.466	0.462	0.460	0.459	0.458	0.458
34	151	0.634	0.622	0.607	0.599	0.595	0.594	0.593	0.592	0.592
36	160	0.772	0.768	0.762	0.758	0.756	0.756	0.755	0.755	0.755
38	169	0.930	0.934	0.942	0.947	0.949	0.950	0.951	0.951	0.951
40	178	1.11	1.12	1.15	1.17	1.18	1.18	1.18	1.18	1.18
42	187	1.32	1.33	1.38	1.42	1.44	1.45	1.46	1.46	1.46
44	196	1.56	1.56	1.64	1.71	1.75	1.77	1.78	1.78	1.78
46	205	1.84	1.83	1.94	2.04	2.10	2.14	2.15	2.16	2.16
48	214	2.16	2.12	2.26	2.41	2.51	2.56	2.58	2.59	2.60
50	222	2.53	2.45	2.61	2.82	2.96	3.03	3.07	3.09	3.10
52	231	2.95	2.82	3.01	3.27	3.47	3.58	3.63	3.66	3.68
54	240	3.43	3.23	3.43	3.77	4.03	4.18	4.27	4.31	4.33
56	249	3.98	3.70	3.90	4.31	4.65	4.86	4.98	5.04	5.07
58	258	4.59	4.22	4.42	4.90	5.34	5.62	5.78	5.86	5.90
60	267	5.28	4.80	4.99	5.54	6.08	6.45	6.66	6.78	6.84
62	276	6.06	5.45	5.61	6.23	6.89	7.36	7.64	7.80	7.88
64	285	6.92	6.18	6.29	6.98	7.76	8.36	8.72	8.93	9.04
66	294	7.89	6.98	7.05	7.78	8.70	9.44	9.91	10.18	10.33
68	302	8.96	7.88	7.87	8.66	9.71	10.61	11.20	11.55	11.75
70	311	10.2	8.9	8.8	9.6	10.8	11.9	12.6	13.1	13.3
72	320	11.5	10.0	9.8	10.6	12.0	13.2	14.1	14.7	15.0
74	329	12.9	11.2	10.9	11.7	13.2	14.7	15.8	16.5	16.9
76	338	14.5	12.5	12.1	12.9	14.5	16.2	17.5	18.4	18.9
78	347	16.2	13.9	13.4	14.2	15.9	17.8	19.4	20.5	21.1
80	356	18.2	15.5	14.8	15.6	17.4	19.6	21.4	22.7	23.5
82	365	20.2	17.2	16.4	17.2	19.1	21.4	23.5	25.1	26.1
84	374	22.5	19.1	18.1	18.8	20.8	23.4	25.8	27.6	28.8
86	383	25.0	21.2	19.9	20.6	22.6	25.5	28.2	30.4	31.8
88	391	27.6	23.4	21.9	22.5	24.6	27.7	30.7	33.2	35.0
90	400	30.5	25.8	24.1	24.6	26.8	30.0	33.4	36.3	38.3

Conversion: 1 in = 25.4 mm.

Analysis period

years

Location

Assumed SN or D =____________ in

Granular soils:

(3.6)

Analysis period =_____ 20____ years

Assumed SN or D =_____ 9_____ in

	Current	Growth	Design	ESAL	Design
Vehicle types	traffic (A)	factors (B)	traffic (C)	factor (D)	ESAL (E)
		2%
Passenger cars	5,925	24.30	52,551,787	0.0008	42,041
Buses	35	24.30	310,433	0.6806	211,280
Panel and pickup trucks	1,135	24.30	10,066,882	0.0122	122,816
Other 2-axle/4-tire trucks	3	24.30	26,609	0.0052	138
2-axle/6-tire trucks	372	24.30	3,299,454	0.1890	623,597
3 or more axle trucks All single-unit trucks	34	24.30	301,563	0.1303	39,294
3-axle tractor semitrailers	19	24.30	168,521	0.8646	145,703
4-axle tractor semitrailers	49	24.30	434,606	0.6560	285,101
5+ axle tractor semitrailers All tractor semitrailers	1,880	24.30	16,674,660	2.3719	39,550,626
5-axle double trailers	103	24.30	913,559	2.3187	2,118,268
6+ axle double trailers All double trailer combos	0	24.30
3-axle truck-trailers	208	24.30	1,844,856	0.0152	28,042
4-axle truck-trailers	305	24.30	2,705,198	0.0152	41,119
5+ axle truck-trailers All truck-trailer combos	125	24.30	1,108,688	0.5317	589,489
All vehicles	10,193		90,406,816	Design ESAL	43,772,314

Location

Example 1

Source: Guide for Design of Pavement Structures, American Association of State Highway and

Transportation Officials, Washington, D. C., 1993, with permission.

TABLE 3.21 Equivalency Factors for Determining ESAL

	Rigid pavement	Flexible pavement
Function classification	B	C	B	C
Rural interstate	2.27	0.914	1.60	0.735
All other rural	2.16	1.02	1.44	0.777
Urban interstate, freeway, and expressway	2.50	1.48	1.74	1.13
All other urban	1.61	0.673	1.11	0.534

Notes: B = tractor-trucks with semitrailers and trucks with trailers. C = single-unit trucks (2 axles, 6 tires or more).

Source: Ohio Department of Transportation, Location and Design Manual, Vol. 1,

Roadway Design, December 1990, revised October 1992, with permission.

Roadbed Soil Resilient Modulus REPEATED LOAD ACTUATOR

:SOLID BASES

SECTION VIEW

Подпись: NOT TO SCALE Note: LVDT tips shall rest on the triaxial cell itself or on a

plate/bracket which is rigidly attached to the tnaxial cell

FIGURE 3.9 Triaxial test chamber for determining resilient modulus of soil specimen. (From NRC Operational Guide No. SHRP-LTPP-OG-004, “SHRP-LTPP Interim Guide for Laboratory Material Handling and Testing," with permission)

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Roadbed Soil Resilient Modulus

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