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Early research (Bathurst and Jarrett, 1988) [13] found that cellular confinement reinforced gravel bases are "equivalent to about twice the thickness of unreinforced gravel bases" and that geocells performed better than single sheet reinforcement schemes (geotextiles and geogrids) and were more effective in reducing lateral spreading of infill under loading than conventional reinforced bases.
Fatigue testing is a specialised form of mechanical testing that is performed by applying cyclic loading to a coupon or structure. These tests are used either to generate fatigue life and crack growth data, identify critical locations or demonstrate the safety of a structure that may be susceptible to fatigue.
The term fatigue refers to the effect of cyclic or intermittent loads. Cyclic loading due to either oscillating mechanical stress or to alternate heating and cooling is more detrimental than static loading. Under cyclic load, cracks initiate at localized sites within the part and these extend in size during cycling.
High cycle fatigue strength (about 10 4 to 10 8 cycles) can be described by stress-based parameters. A load-controlled servo-hydraulic test rig is commonly used in these tests, with frequencies of around 20–50 Hz. Other sorts of machines—like resonant magnetic machines—can also be used, to achieve frequencies up to 250 Hz.
Low cycle fatigue (LCF) has two fundamental characteristics: plastic deformation in each cycle; and low cycle phenomenon, in which the materials have finite endurance for this type of load. The term cycle refers to repeated applications of stress that lead to eventual fatigue and failure; low-cycle pertains to a long period between applications.
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Static load testing is an in situ type of load testing used in geotechnical investigation to determine the bearing capacity of deep foundations prior to the construction of a building. It differs from the statnamic load test and dynamic load testing in that the pressure applied to the pile is slower.