base for slab-on-grade???

[boffintech]

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?

 

[SlideRuleEra]

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.

http://www.SlideRuleEra.net

 

[Ron]

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.