| Test Information | |
| Year | 1986 |
| Test Location | University of Houston Foundation Test Facility, TEXAS, USA |
| Test Type | Large Scale |
| Reference | Morrison, C., and Reese, L. C. (1986). “A lateral-load test of full-scale pile group in sand.” GR86-1, FHWA, Washington D.C. |
| Purpose | Analysis and Comprehension of Pile Groups |
| Keywords | p-y curves;pile groups; p-multipliers; group efficiency; lateral loads; scour |
| Soil Information | |
| Soil Type | Sand |
| Soil Description | The native-clay soil (stiff-OC Beaumont clay) was removed from the upper portion of the piles and replaced with clean medium dense sand. |
| Pile Information | |
| Pile Material | Steel with Grout Fill |
| Pile Placement Method | Driven closed-ended |
| Pile Cross Section | Circular |
| Outside Section | 10.75 in (27.3 cm) |
| Wall Thickness | 0.365 in |
| Test Configuration | |
| Test Configuration | Pile Group |
| Pile Spacing | 3D |
| Group Arrangement | Box Arrangement |
| Test Columns | 3 |
| Test Rows | 3 |
| Head Boundary Condition | Free |
| Loading | |
| Type of Loading | Static Two-Way Cyclic |
| Axial Load | N/A |
| Load Application | A drilled shaft 6ft in diameter and 36 ft deep had been installed at the site and was used in this project. |
| Test Results | |
| Max Top Displacement | 4.2 cm |
| Deflection | 0.10 diam |
| Analysis Method | |
| Comparison with P-Y Curves | Reese, Cox, Koop (19875) and Modified RCK (MRCK=RCK*1.55) |
| Soil Model | DEFPIG, Focht-Koch, Single-Pile, Bogart-Matlock |
| Software Used | COM624, DEFPIG |
| Group Efficiency Factor | 0.58-0.9 |
| P-Multipliers (lead, 2nd, 3rd, n-th rows) | 0.8, 0.4, 0.36 |
| Conclusions | |
| Comparisons | •It is believed that the p-y curves generated by MRCK model the single pile response in an adeguate way; •Even if methods used were generally succesfull in predicting deflections and maximum moments, no method was able to make correct predictions of deflections, maximum moment and the distribution of load to the piles. (see Table) |
| Outcomes | • The response of the single pile to lateral load is stiffer than the response of the average pile in the pile group. • For both the single pile and the pile group, the response of the piles to static loading is stiffer than the response to cyclic loading. • The distribution of load to the piles in the group is not uniform. The leading row takes a larger portion of the load than the middle row, which in turn takes a larger portion than the trailing row. • The ultimate soil resistance for the leading row of piles is larger than the ultimate soil resistance for the middle row which is in turn larger than that for the trailing row. |
