I tend to disagree. The skin friction is a bond stress which would not be effected by the removed weight of soil. The base resistance is determined by a limiting value that is empirically based on load test data.
I believe strength should be evaluated considering the weight of the shaft. FHWA...
But wouldn't the load test show this? PTI sets limits for the Apparent Free Stressing Length measured during load tests. If the load test indicates that the Apparent Free Stressing Length is between 80% of the Unbonded Length assumed in the design and 100% of the Unbonded Length plus 50% of the...
There's several failure modes for something like this. One failure mode is the grout/ground interface. This is usually assumed to be the bonded length of the anchor. It is verified by load tests that approximate the unbonded length through deflection measurements. Another failure mode assumes...
Mp should always be Fy*Zx
You will calculate an Mn for each failure mode (i.e. F2.1, F2.2, etc)
It is very possible that your Mn for LTB is higher than your Mn for yielding. This will happen if your unbraced length (Lb) does not fall within the applicable range for an LTB failure. It is just...
Its been a while, but I remember finding a couple issues like this with examples and equations in NCMA. I think there are several spots where equations are labeled incorrectly, variables are inconsistent, and values do not make sense
I think it would boil down to the use of the column/bracket. Is it a permanent part of a specific structure or an engineered product for repeated use?
There are plenty of engineered products that are used repeatedly within given guidelines. Trench boxes, equipment, concrete forms, scaffolding...
1. 3/4" is pretty typical for 4000 psi around me
2. In general the aggregate is filler material and smaller aggregate leads to a stronger mix (there are lots of other variables)
3. This will depend on gradation (well graded vs poorly graded)
4. Not sure.
5. Yes. Around here a 3/8" 4000 psi...
You would run a string with a line level on it to get a theoretically perfect, level reference line. It can be at any arbitrary elevation (i.e. 1-2ft off the floor so you don't have to climb any columns) as long as it is constant for all measurements. Shoot the laser up at the bottom of the...
You could invest in a 3D laser scanner https://leica-geosystems.com/en-us/products/laser-scanners/scanners/leica-scanstation-p50
Run a string line down low and shoot up with a laser https://www.homedepot.com/p/Bosch-100-ft-Laser-Measure-GLM-30/205910686
No matter what method you use, you're...
It is probably regional preference or requirements from local DOT/other agencies. ASTM allows samplers to be 18" to 30" long.
Maybe the larger samplers are used to get more material for index testing?
I mostly see 24" samplers. I have never seen a 30" sampler
For FHWA, the sum of the middle 2 readings is taken. The 1st reading is ignored because "it is a seating drive". The 4th reading is ignored "due to sampler side friction". I believe FHWA adopts the ASTM standard(more or less).
Check out FHWA Geotechnical Engineering Circular 5. They have some...
Run the string line under the ceiling and measure up.
You could use an auto level/transit and grade rod, rotary laser, or construction altimiter.
If you want to be really technical/expensive, there's instrumentation for measuring the settlement profile of an embankment. I don't see why it...
Most manufacturers publish the individual helix plate capacity for their anchors. Are you designing your own helix plates?
Hubbell Power Systems (A.B. Chance) Manual
https://www.masongradyllc.com/wp-content/uploads/2017/09/DesignManualForEngineers.pdf
I recently did some roadside DMS signs according to AASHTO LRFD Spec for Highway Signs, Luminaries, and Traffic Signals. Wind loads ended up being 40 psf (Extreme I)and 21 psf (Service I).
You're state DOT (or similar) probably has a standard detail based on sign area with prescriptive designs.
A "legal" excavation for OSHA is a 1.5H:1V (approx. 56 degrees from vertical) for most soils. The theoretical failure plane is approximately 30 degrees from vertical for most granular soils. Assuming the excavation is made "legally" and without shoring, the native material would be excavated...
Check out AISC Steel Design Guide 1. It can be found on google. Is there a reason you can't convert the moment to a force couple and just evaluate axial force and shear? The AISC design guide has a lot of good examples.
Table 8-5 is for eccentrically loaded welds. It looks like your weld is not eccentrically loaded. I think you would just want to use equation J2-4 and J2-5.
In general you can substitute a larger stitched weld for a smaller continuous weld. I believe AISC has guidelines for minimum lengths and...
I've had EOR demand calculations for this before. I was able to make it work using purely weak axis bending strength for soldier piles (HP section). I've never had to try it with sheets.
...loads are low enough that rebar is not required for strength.
For AASHTO LRFD 7, I used Section 5.11.2.1 to calculate development length (ldh= 1.25*Ab*Fy/sqrt(f'c)) and considered it a Class C splice (ld= 1.7*ldh). I used this distance as the overlap distance on the circular tie.
These...
