×
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

base for slab-on-grade???

base for slab-on-grade???

base for slab-on-grade???

(OP)
On the contract drawings the engineer has specified that the slab-on-grade be placed on “6 inches of granular subbase compacted to 98% of its standard proctor maximum dry density in accordance with ASTM-D698".

The spec book defines “granular subbase” as follows: “Granular subbase shall be sound and free-draining, such as sand, gravel or crushed stone with less than 10% passing the #200 sieve.  Maximum diameter shall be 1-1/2.”

Is the engineer giving the contractor 3 choices for granular subbase: sand, #57 stone, or crusher-run?

The spec book also has a section on “Placement of Granular Subbase” which reads:  “Compact Granular Subbase to 95 % of the maximum dry density as measured by the Standard Proctor, ASTM D698, with a water content within +3/-3 percent of the optimum moisture content.”

A proctor on #57 stone?  What’s that all about?  Would that be a method A, B, or C?

Should this stuff make sense to me or am I missing something?

RE: base for slab-on-grade???

Looks like the Engineer did not coordinate their drawing notes with the contents of the specification - happens often. Many times contract documents even include "boiler plate" language that says something like "...if the Drawings and Specifications conflict, the Drawings have precedence..." (of course the it could be the Specifications that have precedence - have seen it both ways)

The way it is written, sounds like the Contractor does have three options - suggest letting the Engineer decide - could be financial consequences (Change Order).

I don't think you are missing anything. In fact you seem to have a clearer view of the situation than the Engineer - I don't think it is "written" anywhere that contract documents have to make sense - although they should.

www.SlideRuleEra.net reading

RE: base for slab-on-grade???

boffintech...if you take all the requirements together, you immediately knock out the #57 stone as there is no definitive way to obtain a standard proctor on stone alone.  The crusher run material would also be dropped out unless it has enough finer material to achieve some level of compactability.  That leaves sand.

As SRE said...poor coordination of the specs.

For this, I would consider that you have an unclear requirement and you should formally request an interpretation by the Engineer or Architect of Record.

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