Gneiss Rock - Soil testing engineering - Eng-Tips
Oct 29, 2019 · gneiss is a reference to degree of metamorphism. Shale is a sedimentary rock. When metamorphosed it goes by degree to slate, phyllite, and gneisse. As the degree of metamorphism increases (higher pressures and temperatures), there is opportunity for mineral grains to grow. Such tendency (and pressures) align bands of minerals.
rock anchor in Gneiss w/ Rec60%&RQD47% - Eng-Tips
Jan 4, 2006 · I am designing the rock tiedown anchors to take uplift load of the footing due to temperature load. At the site boring, 2 rock corings were conducted, both had a 2' of void out of 5' run, that implied a Rec 60%. The RQD is 47%. Rock is Gneiss. Unfortunately, due to the technical difficulty the boring had to end there.
Blasting Bedrock Next to Existing Structure - Eng-Tips
Nov 15, 2001 · The rock is a gneiss, slightly weathered at the surface. Someone told me of a procedure like blasting - The rock is drilled (like blasting), but instead of using explosives, the drill holes are pressure injected with water, and when the pressure is high enough the rock fractures.
Rock Allowable Bearing Capacity - Foundation engineering - Eng …
Oct 14, 2005 · The formula in AASHTO HB-17 is qult (bearing on rock) = Nms * Co. where Co = rock UCS. Nms = f (RQD) You could also request copies of the original geotechnical investigation report and ask if the original cores (if performed) are available. The original geotech report should include RQD values if cores were performed.
Density of 3" crushed rock - Earthwork/grading engineering - Eng …
Jun 30, 2008 · Bear in mind coarser soils have a lower void ratio than finer soils. So, just because you can see the voids of a large aggregate material, does not mean the void ratio is greater than a fine grained soil. Given a void ratio of 0.3 and a specific gravity of 2.7, the dry density would be: GammaD=0.7*62.4*2.7=118 pcf.
Foundation of Bedrock - Foundation engineering - Eng-Tips
Oct 13, 2010 · These are a function of the size of foundation, the size of the dataset and the variability or standard deviation or COV. The EC7 tells you which is the appropriate point-estiamte value for the whole distribution; with a 30% COV and a small dataset and small foundations it may become pretty low and cautious.
Footing and Foundations on surface Bedrock - Eng-Tips
Jul 20, 2009 · It's worth considering isolation joints between the rock- and soil-suported portions of the structure. You might also consider overexcavating the rock 6 inches (15 cm) or so and backfilling with gravel or compacted native soil to provide more uniform foundation support. swazimatt (Civil/Environmental) 20 Aug 09 05:15.
Shrink/swell factors for earthwork calculations - Eng-Tips
Jan 14, 2007 · I was in fairly cohesive soils and a good bit of rock. I'm not a soils experts, so I inquired externally about shrink:swell. This is what the Geotechnical Group Manager of an ENR 500 firm said, verbatim. When excavating the rock you can get a pretty high expansion between 30% to 40% swell from in-place volume to loose volume.
AISC Greenbook designation - Concrete Mixes - Eng-Tips
Sep 28, 2002 · The concrete mix designs are per AISC greenbook - in the form: 520-C-2500 (520=lb cement "c"=aggrgate size 2500=psi). The new designation will be metric in the form (I found this formula in a municipality requirement): 310 kg/M (cubed) C 20 MPa. My question is, the conversions do not seem right.
How to calculate Tangent modulus? - Eng-Tips
TGS4 (Mechanical) 10 Nov 11 13:10. The tangent Modulus is just that - the tangent of the stress-strain curve at any particular point. If you have a stress-strain curve, then you can calculate the tangent modulus either symbolically, if you have a formula (derivatives, calculus-type stuff), or numerically (delta stress / delta strain).