Q_ _A_SAND_CREEK.pdf

DTFH6815B00011 10/27/15

WY FLAP 129(1), Sand Creek Road

10/19/15 Question #1

I have a question in regards to the CMU masonry blocks. In the final geotechnical report, it calls for “CMU blocks are readily available as hollow or solid core, flat or cut face units with the following standard dimensions.” My question is how many solid core CMU blocks are needed vs. hollow core? In the paylist items, only 750 sq yd is given for CMU blocks, however in the bid invitation and pay list items, it does not break down the amount of square feet for each hollow and solid core. When watching the GRS-IBS video, it shows layers of solid core at the base, followed by layers of hollow core bricks. I would like to know the percent or the amount of solid core blocks needed for the project.

Response: For the location of each type of block (solid core, hollow core and reinforced concrete filled block) refer to the “Block Type Key” on the Abutment Elevations & Sections sheets for each bridge.

Sheets S7-S9, bridge #1 Sheets S23-S24, bridge #2 Sheets S69-70, bridge #5 Sheets S85-87, bridge #6

The summary of quantities, schedule A, sheet B2, shows the estimated SY of Concrete Masonry Units (CMU) estimated for each bridge location.

The determination of the percentage or amount of each type of block is the contractor’s responsibility.

10/22/15 Question #2

“What is the material requirement for the rail hardware? The plans indicate ASTM A325 but my experience with this type of rail is a different requirement – an AASHTO F1554 Type 105. Is this what is required here?”

Response: The ASTM A325 material requirements for the rail hardware as shown in the IFB are correct. Bid as shown.

Question #3

“The precast concrete supplier be allowed to cast these with a self-consolidating concrete mix?”

Response: The use of a self-consolidating concrete mix is acceptable.

Question #4

“Is there a requirement for the void material? Gage is planning to cast in foam and of course, leave this foam in place in the final product.”

Response: The use of stay in place foam is acceptable. There is no requirement for the void material, there is a “performance” requirement. See FP-03, Subsection 562.03 Design. Design and construct safe and adequate temporary works that will support all loads imposed and provide the necessary rigidity to produce in the final structure, the lines and grades shown on the plans.

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10/22/15 Question #5

The plans indicate that the Geosynthetic reinforcement has a 1370 PSF at 2% strain. 4800 PSF tensile geotextile typically have a 2% strain of 1320 PSF in the crossed machine direction. Is that acceptable in meeting the specifications.

Response: It will be acceptable to use geotextile materials with a minimum ultimate tensile strength of 4800 lb/ft and a required tensile strength of 1320 lb/ft at 2% strain, provided the maximum aggregate sizes is 0.5 inches or larger. This would require the use of AASHTO M43 Size 8. (see the response to question 4. Below)

Question #6

The Webinar seemed to indicate that the solid core block was red color and standard face. Is this what is desired?

Response: The webinar was for information only. Follow the plans and specifications provided for this project.

Question #7

The surfacing aggregate from spec 703-2 gradation has a PI of 8. This is a high level PI and is not available at the local sources. In order to achieve that PI it would require bentonite to be pugmilled into the product which can be very expensive. Is it possible that this spec could be revised as to the levels of

PI?

Response: Provide surface course aggregate meeting the requirements of 703.05 (c) Surface Course Aggregates. The PI shall be as required in table 703-3.

Question #8

The Geotechnical Report indicated that gravel gradations for the GRS backfill be a maximum of 2” material. The Drawings indicate the acceptable size is 89 on AASHTO M43. Size 8 and 57 from the same table are locally available. Would either of those or any additional size from the chart be consider acceptable?

Response: The aggregate backfill shall meet the grading requirements of AASHTO M43, size 89. Size 8 may be used as an alternate.

Question #9

Do temporary traffic routes around the bridge require a design from a professional engineer?

Response: Refer to specification section 104.03 (b) (2) for drawings that require the seal and signature of a professional engineer.