I primarily use limit equilibrium and have started to get into p-y analysis and Ensoft's p-y wall. Limit equilibrium is more of an Ultimate strength approach. If you fully develop the driving stress, by it active or at rest, how much full developed depth of passive pressure, assuming a rigid...
Depending on the slope, I would try drive from the top with hanging leads. The length of the spuds on the stab section may need to be increased. Also you would start the pile slightly up slope, allowing the pile and leads to walk slightly before biting in. The feasibility of this obviously...
matt1829:
I am assuming you are excavating parallel to the tracks. The railroad will generally have a slope line, sometimes referred to as an influence line. It will slope away from the bottom of the tie at a 1:1 or 2:1 slope. Generally they require your excavation limit for the trench to be...
I agree with PEinc and dcarr82775 - you really should get someone with retention design experience. This forum is a great place to learn new things, but a dozen posts will not give you a viable design. Loads need to be computed, and the effect of adding 143 kips will not only effect the...
Pulling piles in clays is significantly easier than pulling piles in stone. Again the best way to do this is to use a vibratory driver/extractor. I would not recomend pulling with a crane,unless you are using a vibratory extractor.
Wether or not the sugrade was frozen at the time of pouring the footing or wall is inmaterial. It is also hard to estimate the percent of frozen materials, because small chunks effect the backfill as much as big chunks. In many granular materials it is difficult to get compaction with out water...
Ron, BAretired and TX structural,
Thanks a lot really appreaciate the help, which is what makes this forum a great resource.
Just for cairification, I meant to say DOT was not accepting strength tests beyond the 28 day test, not the 56 day test.
My understanding of the 21 day strength was that at 28 days, it was generally assumed most of the curing had taken place. It is also exactly 3 weeks from the pour date, so if you pour on a Monday, you could get the break on Monday 4 weeks later.
I have always assumed the selection of 28 days...
I would expect 10-20 tons in sand for resistance. If you use a small vibrator suspended from the backhoe, they will come out easily. Vibrator will not produce a lot of vibration.
The feasibility of sheet piling depends on the soil profile. 20m will require a driving template. You can do a king pile system. The most common way to integrate H-piles and sheet piles are jokers. These are connectors that are welded to the H-piles. The allow the H-pile to receive the sheets...
...the water trapped by the clay particles can not bleed off fast enough, the internal pressure rises and the clay or silt soil structure can fail.
*** Obviously I have not seen the site or any data beyond what you have mentioned. This is just my feeling based on your notes. You may want to...
Air is the key. If you are pouring, standard air should not be a problem. If you are pumping, air can become a problem. Talk to the contractor and pump truck sub about maintaining air. If this is a job that is being put out to bid talk to reputable contractor and pump truck operator you know.
As...
I do not know how the coupons work for square tube, but mill tests are not representative of the strength of the steel for wide flange beams. For beams, the coupons are taken from the center of the web which cools the slowest and thus gains the most strength. It is also generally the the least...
Shop drawing once approved always supercede the structural plans, no matter what is on the approval stamp. This is because the steel is fabricated and erected in accordance with the approved shops, not the structural drawings.
SPT are an index tests of sorts that yield relative density. They are applicable to Silty sands as well as clean sands. They are not useful for cohesive soils. The chief use of SPT's is to estimate the internal friction angle of the soil, from which an estimate bearing capacity can be computed...
The only we have been able to do this in a reasonable manner is to excavate to unfrozen material and backfill right away with clean crushed stone. Generally 3/4 inch works pretty well.
This is a sticky situation. Fortunately there does not appear to be significant risk to the public. True, bad news does not get better with age, and as a contractor, I would probably try to addresses it casually to the DOT. However, many states now have significant penalties for any...
Good Point. This work was above the water table. However, where piles below the water table are exposed, they can deteriorate quickly. I understand that this type of work is common in Boston and when such piles are exposed, they are kept wet by a continuous stream of water running over the pile...
We have done static load testing of existing timber piles under railroad piers. With appropriate shoring, we excavated below the foundation, exposing the piles. We cut out the top foot or two of a pile, poured a collar of self leveling epoxy and jacked against the existing foundation. After the...
