Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Geotech

[Subject Prev][Subject Next][Thread Prev][Thread Next]
We find the same things on the East Coast. I think a big part of the problem 
is liability and the fact that most owners and architects bid geotech 
services. We have one firm out of a dozen or so in the Norfolk area that 
gives good service, actually does some engineering and supports us throughout 
the project. They're a small shop, but we wouldn't go anywhere else by 
choice. If you're not happy with what you get, go somewhere else.

We've also found that it helps to give a detailed scope of work (i.e., if you 
want bearing equations, ask for them). I don't mean that you need to specify 
the number and location of borings, etc. Tell them what the project entails 
and let them propose the exploration program - at least that works better for 
us.

And, if you need the work done by a certain date, put it in your Request for 
Proposal letter and include it in the contract.

We had one recent bad experience with a national geotech firm here. On a 
project that had been designed 10 years ago to be a 4 story addition to an 
existing building and put on the shelf, we went back to the original geotech 
firm to ask them to "update" the original report for a three story building. 
First, they insisted on drilling a new boring. The boring actually indicated 
better soils, yet they gave us lower pile capacities than the original 
report. We even gave them pile driving logs from the original building (at 
which the pile load test was waived because the blow counts were so good). 
Needless to say, they've done their last project for us.

Bill Keen




-----Original Message-----
From: Paul Feather On Behalf Of Paul Feather
Sent: Wednesday, November 04, 1998 10:12 PM
To: SEAOC list message
Subject: Geotech



Here is a topic I would like to offer up for discussion.

It seems like no matter where the project I am working on is located, the
soils report recommendations are almost a foregone conclusion. Low bearing
values and limited information. Apart from the obviously poor sites where
piles or caissons are recommended, the typical values for a traditional pad
footing foundation are equivalent to UBC minimum values (a straight 2000
psf).

Every soils bearing relationship I have ever studied, the bearing capacity
is dependent on the configuration and depth of the foundation, but only once
has a soils report provided equations for bearing with site specific
coefficients to allow for increased values due to width and depth.

Is this a typical condition for the rest of you, or is Southern California
primarily lousy soil?

Are these values realistic, or are the Geo-tech reports heavily influenced
by the 267,000 lawyers in California?

Structural design forces per the 1997 UBC are heavily soil dependent. All of
the new base shear equations, zone factors, and period values are
interrelated with the parameters for the top 100 feet of soil. The soils
report will have a large impact on the configuration and economy of the
final design.

I would be interested in hearing your opinions.

Paul Feather PE