mfio:
First I see nothing incorrect with your approach using a cone of rock to evaluate uplift resistance. In design, this ia plausible. The use of rock anchors below the drilled pile is also geasible and can perhaps be cost effective. You may wish to review the texts "Foundations in Tension"...
Interesting question. The reason for overexcavating 0.5m and backfilling presumably with gravel is for this layer to act amongst other aspects as a cushion similar to a mudslab often used if the ground is a bit soft and mushy. However, it is hardly likely that this thickness is required for weak...
ONENGINEER:
Pile design by static analysis is an ever revolving topic and numerous articles have been written on the subject. Traditionally the relationship you have used shaft resistance plus toe resistance divided by a Factor of Safety in working stress design (WSD) is often accepted to...
netjoy:
The factors fc and fphi relate to the cohesion and friction angle of the soil. These are modification factors (resistance factors) which reduce the values of cohesion and friction and are known as partial factors. This approach is used by the Eurocodes and not by the North American LRFD...
You need to consider that with the water in the pond case that there is a buoyancy effect on some slices which reduces the driving forces depending on the location of critical circle and hence could lead to a higher factor of safety than the no water case.
Some comments on issue
It is possible hat you may have a problem related to the construction of drainage discharge and you may be collecting groundwater from the adjacent homes.
It is possible that you can with the help of your neighbours use a dye as a tracer by inserting some in each...
Can you say if your neighbours also have sump pumps and if they are working. Most likely they do. If so then it is likely that your groundwater level is high and hence the need for the sump pump. I presume that this condition gets worse when there is rainfall since the ground is subject to...
Mudcatwilly:
Just a thought looking at the ease of removal of piles first. I presume that in reoving the piles you would first remove the backfill against the wall, then the lagging. Could you use a hydovac truck to remove the stone fill from the pile holes. At least some can be removed by this...
Very interesting case and comments. Lawyers love these cases when soil below floor slabs settle and footings undergoe settlement. This issue has been with us for years and would not go away unless we are able to have full time inspection of all backfill to be placed on sites. Often this is done...
Dozerman's answer is correct. However, the overall expectation is that water from rainfall and snowmelt precipitation does not infiltrate the subsurface via the "wound" that the construction of the building foundation has placed on the earth.
Generally, the earth and concrete stem wall fail to...
tbone73
Adding on to the existing footing is possible. The addition is to be such that the dimensions of the combined footing would produce a uniform pressure under the combined footing. This would result if the resultant passes through the centroid of the footing contact area. The width of the...
I am not very familiar with your code, but would this connection have something to do with lateral stability of your overall structure in the light of seismic design considerations.
It takes about 2 mm of movement to invoke shaft resistance. Pile compression under loading may be able to create this effect or reconsolidation of the soil around a pile after installation. However, there are certain conditions which many use to decide whether to use toe resistance only, or toe...
Some Cautions. Despite that the water table is below the wall level, one should look at a few other issues. Is there a likelihood for water from surface runoff to seep downwards in the subsoils. Remember the placement of soil against a wall is like putting a frictionless wound at the join...
Interesting case. A few questions. What is the reason for failure of the riverbank. Has this occurred because of toe erosion caused by river action or has this failure resulted from groundwater seepage from higher fround to the river. Are there indications of similar failure outside the location...
A Structural Engineer once said we pay very little attention to a subject - houses which some many millions are being spent on daily basis and within which we also spend most of our lives.
The responses given so far are enlightening as it demonstrates how complex a commonly presumed...
adfo:
While excavation allows one to see the system and evaluate the condition, there is a possibility of checking on the system using non destructive testing as well. This may be used in combination with a limited amount of destructive testing. As to the non destructive testing, you may wish...
DCR1:
There is alot being done without consolidation testing as well. Perhaps amusementpark should provide the loads and the subsurface conditions - boring log, and depth of footing etc so that one can determine if testing is required. I guess your diasgreement is based on your thoughts and my...
DPAJR:
I would suggest that you investigate the situation properly before writing your report. very often what seems obvious at first review may not be the cause. Just a few questions:
Is this a new home - Likely not
Was the first Contractor the new building Contractor or was he called in to...
