Surge load tests to ASTM D3966
Surge load tests to ASTM D3966
(OP)
Reviewing a previous specification on load tests to piles, I have noted that this calls for "surge loading in accordance with paragraphs 6.4.1 and 6.4.3 of ASTM 3966. This shall consist of loading and unloading the piles to a load of 4 tons (lateral load design capacity), for a total of fifty (50) loading cycles. Only lateral movements of the piles shall be monitored during surge loading" I cannot see the reason for including this test in this particular instance, but as this is from a clients previous specification on the same site, he is uncomfortable in dropping the test. The site comprises loose sand (1-3m thick) on friable limestone (1-3m thick) on loose to medium dense to dense sand (6-10m thick) on dense sand. Can anyone help me by clarifying the need or benefit of carrying out such lateral load tests?





RE: Surge load tests to ASTM D3966
What changes, if any, have been made between the previous and current foundation systems?
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Surge load tests to ASTM D3966
RE: Surge load tests to ASTM D3966
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Surge load tests to ASTM D3966
RE: Surge load tests to ASTM D3966
I assume that the original specification has to do with earthquake loads. The Kuwaitis and Saudis have done a good bit of study of the behavior of the calcareous soils, since those materials do not behave like the "normal" soils described in the majority of the geotechnical literature. You should check with the local universities for advice. In "normal" soils, permanent cavities will only form adjacent to piers/piles that have been subject to "significant" lateral loads. In "normal" soils, the cavities caused by "small" loads will generally heal over time; sometimes the healing occurs almost immediately. However, this does not happen in those calcareous soils where particle crushing occurs, and in general the healing process is delayed in calcareous materials. The principal reason appears to be the general lack of shrink/swell behavior in these materials.
The formation of permanent cavities along the piles will significantly affect the dynamic performance of the pile foundation system. This is a very big deal if you are constructing an oil/gas facility, or a refinery.
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Surge load tests to ASTM D3966
The soils on the site are considered to behave as siliceous soils, however we have decided to clarify the scope of the EPC contractors geo-technical investigation to include the comprehensive sampling and testing, physical and chemical, to classify the physical nature and mineralogy of the soils, including calcium sulphate and carbonate content and also to determine the susceptibility of soils to weaken under repeated cyclic loads.