This test was performed as part of a production project in Halmstad, Sweden. The pre-testing was performed to verify performance of the MDM columns as the foundation method for a planned 5 story parking garage.
The testing consisted of core samples, pull-out of whole columns and live loading.
The soil consisted of a top layer of sand to approximately 2 meters depth. From 2-6 meters silt and silty clay and under that mostly clay.
Two different test sections were installed. Both consisted of 9 columns in an overlap pattern. In one section the columns were 13 meters deep, in the other, 17 meters. Directly after installation the top 50cm was excavated, exposing the column tops. After initial curing of 1-2 days, a concrete pad was poured directly on top of the columns, providing a direct load transfer platform/zone.
This same procedure was also used for the production columns.
After 28 days curing, the columns were exposed to a live load test. Each of the two pads were subjected to a maximum load of 300 ton over time. Permanent settlement on the 13 meter columns were approximately 13mm and on the 17 meter deep ones, 0mm.
Core samples were taken from single columns, installed adjacent to the test pads.
In addition, whole columns were excavated by means of pull-out. This was accomplished by inserting a GE-WE rod in the center of a freshly installed column and after a 7 days cure, pulling it out with a mobile crane. This also provided valuable data on uplift capacities, see pdf download at bottom of page.
Hercules Grundläggning AB
LC TEchnology, Inc.
Overlapping column pattern
Excavated column dissected for inspection
Whole column pulled out
Concrete pad cast on top of columns Tell-tales anchored at bottom and center depths
Pad shown with Titan rods at four corners to act as hold-downs for live load test