a tremie slab of less than about 1 meter would be the min thickness of the slab is placed underwater by a very experience crew but a thickness of 1.5 meter may be much better. Once the cofferdam is dewatered make sure you check uplift.
In addition, you need to make sure the cofferdam is...
using a water loading with a FS of yield stress in the sheet pile makes now sense even if the code recommends this.
This code is not conservative for this condition asce standard 7-05 requires factor load of 1.4(D+Fluid)
also another load condition is 0.9d + 1.0 E + 1.6 H(lateral or water...
It is time to start pushing back from the bad decisions. I have no problem with ACI, AISC. I have a problem with a building code that is badly developed and so complex that normal engineers can not easily understand and apply the code.
Does not sound like anyone has any idea about this. There has not been must testing doing to find real loading conditions. The arching for sand would not be time dependent. The arching of soil is a complex system that is not easily modeled by FEA or other means.
jack,
I would consider rebracing the wall at the bottom while the new slurry wall is placed. This could be providing additional tieback close to the toe as one option.
You need to be concerned about both lateral movement of the toe and vertical support of the wall.
This work is tricky and...
Secant piles are not designed to have spacing between the piles, the arching between the pile is total dependent on the cohesion of the soil which my vary. The only reason i can imagine using secant pile is to limit deflection and potential ground lose where settlement is an issue.
I have use...
This whole discussion amazes me. Does anyone ever use drawings to show what they are talking about. The type of design are critical to new structures and how you build the project. The simple solution is to install rakers and a waler to brace the wall. A 17'6 cantilever is a major structure...
This is too complex to try to solve over the net and with this forum. Without some detailed study I would be very careful. A 16'-0 cantilever needs some experience and judgement. Just be carefulhttp://www.wmta.com/
You made a good point. One of the questions is how to make the code simple for designs that require a simple approach with the ability to make a more detailed analysis if time and money warrant the effort. The present code does not consider this and it is a big missing.
I am not clear about a few things which could effect the surcharge loading to your wall. A surcharge of 250 psf/ft is a normal surcharge for heavy construction loading. But the actual loading of the loader may control. Normally i would expect so shoulder on the travel way and a width for...
I am shocked to see what is being passed as the new building code. I wonder why more people are not up in arms with what is going on with the codes. Thousands of pages of paper are not making our building better. Where is the engineering judgement and skill of making something work?
Love to...
This whole revisions is terrible. I have never read any document that is so poorly written and unclear. Hundreds of pages of data in a code does not help anyone.
All it seems to be doing is making the analysis of structure more complicated.
Based on my experience the surcharge load is usually cut off at the bottom of the excavation due to the fact that the passive resistance of the soil below grade is an order of magnitude greater than the active load.http://www.wmta.com/
Be very careful with the soft clay soil. The shaft loads may be very very high. I would never depend on a computer program to design a cofferdam like this. There have been a number of failures of cofferdams in soft clay. It is my experience that dewatering of soft clay is not possible, but...
