I have designed and installed litarally millions of square feet of virtually all of the walls described above. Here are some thoughts:
Redi-Rock: big and pretty but expensive to install. 12 feet tall will work without grid with the 60" base IF everything is level on top and bottom. A "bobcat"...
Keep in mind the live load is an "equivilent" surcharge load. From what you provide, you have a 200,000 lb vehicle on the ramp. I would equate that load and see what you get. This sounds similar to loading used in mine operations. It may require a reinforced concrete slab to distribute the load...
External stability is performed for the barrier and counter balance slab design and then the dymamic impact loads are then analyzed for internal stability of the MSE wall. The FHWA design manual illustrates this in example 6.
http://www.fhwa.dot.gov/engineering/geotech/pubs/nhi10024/nhi10024.pdf
Sorry you don't agree. I have used the helicals on similar structures of the same height with great results. Cost is less than sheet piles with tiebacks. With 11' feet of height and saturated foundation material, you will have a very hard time getting Redi Rock to work. Sorry, I've tried that too.
I have utilized helical anchors to stabilize failed timber walls similar to your situation. You can then face it with modular block. The anchors can be installed from the top and once the soil is stable, a block veneer can be installed from the bottom up. It only requires about 2 feet to work...
The bearing resistance factor for say...an MSE wall would be 0.65 per the 2007 AASHTO table. This would produce an unfactored bearing resistance of 1450/.65 = 2230 psf. Still a somewhat soft material.
"Factored Bearing Resistance" is the LRFD term used to describe the nominal bearing resistance (bearing capacity) multiplied by the AASHTO LRFD resistance factor for bearing resistance (per the AASHTO 2007 table 11.5.6-1). The bearing resistance (qr = Rf*qn) must be greater than the factored...
I suggest hiring an estimator with experience. It will cost more but you will learn faster and have some security that the bids you are submitting will likely be competetive. You don't want to submit a bid that is way off to a GC and have a bad first impression. As you know, times are hard in...
I also agree with BigH. We normally use 0 to -2% for sands in the middle east. Moisture control of sands with less than 10% fines can be difficult in the arid climate. Adequate density is easily achieved in a slightly dry condition.
Delta sigma h is applied as a uniform load to the retained soil. So, your applied load is the surcharge load x the height of the lower wall x Ka. This is added to the retained load (1/2 gamma h squared Ka). Also, MSEW is designed specifically for reinforced walls not gravity walls. It takes a...
MSEW confirmed what you knew, that cohesion in the foundation soils increases sliding resistance. That does not indicate whether or not the analysis is appropriate for you situation. I agree with IDS, a global stability analysis will likely end the discussion. Flip the design into ReSSA and see...
Yes you have to include the surcharge of the upper wall. If the distance between the tiers is less than 2H of the lower tier, you should include the surcharge. Basically you would take the applied bearing pressure from the upper tier and apply it as dead load on the lower for internal and...
"Industry standard" for designing MSE walls is to exclude cohesion. You run the risk of problems during review if your design depends on cohesion to satisfy the minimum FS. I assume you are trying to limit L due to site constraints. In my opinion, you are in a better position to support your...
