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I disagree. Providing "soil property" values that already contain the stability factors leads to confusion. It is quite possible that an inexperienced designer becoming accustomed to this practice may assume the stability factors are included when they're not.

Yeah cap4000 that sounds about right thanks for the reply. Typically for passive the first foot to six inches of soil is neglected, our office policy. I was more or less entertaining the idea of whether it was necessary seeing that the soils engineer may already be including this contingency...

Ooops...need to clarify. The 1/3 reduction in passive is for sliding when friction and passive are combined. I have also seen it where it is specified the reduction may be taken in either friction or passive when they are combined.

The reduction is in addition to the 1.5 factor of safety for stability analysis (sliding and moment). And this is not the first time I have seen an instance of this recommendation. I have also had soils engineers provide the stability safety factor within their design values, as PEinc suggests...

Does anyone know where the origin of the recommendation for 1/3 reduction in passive pressure? The 1997 UBC Table 18-I-A explicitely states that the two may be combined without reduction. These office standards are funny. I had the soils engineer ask me where the reduction came from--he was...

Inspect the existing structure, make sure there is no structural deficiency. Determine if the existing structure meets the present design loads. If yes, widen per existing. This way the addition will have the same response and stiffness as the existing.

Go jointless, The trend has been occuring since about 1940. The downside is the that people don't like to see cracks.

Hey Focht3, Take it easy. Thank you for writing in and all, but geez try not to make it so personal. I hold the geotechnical engineer's recommendations and opinions in the highest regards--and will not make a move without his report and consultation. I would never attempt to do the...

Focht's last statement is correct: soils engineering is a calculated risk. Charlierock's last statement is incorrect. Seismically induced forces will occur. It is unlikely the wall and backfill will move together. However, since you have not specified the type of wall? It is definitely...

Retaining walls have held up well in earth quakes, no failures that I know of. The CBC only requires earthquake design for walls over 12 ft in height that are state owned and what not. In most instances, the engineer designing the retaining wall will take the earthquake into account if and how...

My steel design experience is virtually nill. And when I am called upon, I use ASD. So my "opinion" here is not based on experience. So, This is my understanding: 1) under the service loading condition the joint remains slip critical and should be checked accordingly, 2) under factored loads...

My guess is that the steel will eat through the aluminum--at what rate I have no idea. Maybe someone else will know...

Here's my problem: a thread posted in the bridge engineering forum mentions type N, type F, and type X bolts. I'm missing something, what are type N, type F, and type X bolts? Even making the assumption that these are referring to connection types this still doesn't jibe with the type F. I...

Yeah, maintenance is the problem with every product on the market. There will not be any lawn mowings the slope is a little steeper than 1.5:1. The whole thing is a premanufactured unit, with an optional geotextile filter bag that fits in the "strainer." Since I am an engineer, I...

I'm considering specifying some yard drain/basins that are similar to a coffee maker (i.e. water drains through a conical insert with holes in it that can be removed and emptied). In additon the insert may be fitted with a geotextile fabric. The filter fabric insert, if not permanent, might...

"alternative loading"

Someone that works with reinforced concrete on a regular basis should have designed the tanks. For instance, a loading which might occur is the possibility of the ground water table rising while the tank was empty. Muggles comment above is as credible as my comments about biological septic...

Take care, scour is the most common cause of failure!

trilinga, No, obviously, moment distribution cannot solve for natural frequencies. I was speaking of "the matrix method" as it applies to creating a stiffness matrix (composed of stick elements only), applying the boundary conditions, and solving for the member forces displacements...

Moment distribution is my favorite method of structural analysis. Even though this thread appears a little stale. So here's my take on everyone's comments: JAE, A more adsact description of moment distribution analysis is that it is a "numerical method." It is also a lot harder to...