×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

(OP)
In designing an anchored bulkhead without specific geotech info, is it right to use the lateral bearing values in the IBC table 1804.2 for passive resistance at toe of pile? These numbers seem very conservative? What assumptions do they include do they include?  What if the soil is submerged how do/should you use this value...backcalc a Kp multiply against an assumed submerged unit weight? Also, seeing the IBC values are conservative, are there any minimum factors of safety prescribed in the code for design, I cannot find them? Any help help would be appreciated.

RE: HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

I hate that table.

If you have any condition that is not textbook, straight to the point, no deviation, then the values are conservative.  If there is anything out of the ordinary, _anything_, get the geotech information you need.

Factor of safety applied?  well, you can only determine that if you know the actual conditions and appropriate values, right?

RE: HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

Go to slideruleera's website ( I thinkt is slideruleera.net, but I am not sure and download the US Steel Steel Sheetpiling Design Manual. This is a great reference for designing bulkheads. Typically for sandy soils a bouyant wt of 65 pcf is a value I will use absent any better information. Bulkheads can be designed with two diffent approaches to factor of safety. One is to use no factor of safety to calulate geoemetry and stresses. Then the toe is increased 20%. The other method which I use is to derate the passive pressure by a factor of 1.5. I ussually compute passive pressure based on log sprial theory. Hope this helps.

RE: HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

Just a few suggestions on how to figure out a table from any source.

1. Search the table for footnotes, usually contain usefull information for better understanding, or references for further reading.
2. Contact the source directly.
3. Looking for person that has the similar experience in the forum/communities as you have done here.

If all failed, I would do:

4. Backcal a few values given in the table:
- Determine soil type and set its properties from reputable sources, textbook in general.
- Calculate and compare the results (note, for certain type of soil this may involve several cals. For example, sand - internal friction ranges from 27 - 35 degrees, density ....so on)

After that, your number may or may not come close. If not, you have to repeat the whole cycle again, or give up using the table you don't understand.

I will do the above for my own good only (understand how the table was constructed). For real project, get geotech involved, unless you are quite confident on what you are facing.

RE: HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

consult a geotech...and yes those tables are conservative in the sense that it's impossible to accurately describe every site with a handy dandy table. get a geotech to give you site specific information. it will also reduce your liability and ultimately give the client a more cost-effective design/product.

RE: HOW TO USE LATERAL SOIL BEARING IBC TABLE 1804.2?

In all likelihood, consulting a geotech will get you much higher allowable values than these tables, saving design and construction $$$.

He will also need to know the type of structure involved in the design, as some structures are less critical than others, so the pile is allowed to impart a larger load to the soil matrix.

 

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources