This type of test is traditionally the most commonly used in South Africa, but the INTERNALLY JACKED TEST done by Tambew can usually be more economical.
The most commonly used standard specification in South Africa is SANS 0120:Part 2 Section F – 1983 Piling, Clause 7.4 British Procedure. This requires the load to be imposed in increments of 25% of working load (WL) up to WL; then unloaded quickly; then loaded in increments of 25% of WL up to 150% of WL; then unloaded quickly. At each increment of load it is to be held constant until the rate of settlement is <0.2mm per hour, or for 24 hours, whichever comes first. For piles in clay soils this test can take more than a full week to do.
An alternative specification is the “Quick Load Test Method” of ASTM D1143 “Standard Test Method for Pile Under Static Axial Compressive Load”, which can be completed in one day.
Tambew does not have the jacks or reaction beam equipment to do the head load test, except for very small piles. However we do offer the service of determining further information about the mechanics of a pile’s behaviour by using Strain Rods. Because this requires a Tambew operative to be on site throughout the test, the service of actually executing the load test (using the loading equipment set up by the piling contractor and displacement equipment by Tambew) is also offered. See LOAD TRANSFER TO SOIL on page LOAD TESTING for more information about Strain Rods.
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