Contractor questions on Lock and Dam 3 Upper.pdf

SUBJECT: Contractor questions on Lock and Dam 3 Upper Embankments.

(1) Upon review of the specifications for W912ES-09-0008 the material sources for Lock and Dam 3 Embankments Note 3 states that the government must purchase and supply this material to the contractor.

Answer: This is addressed in Amendment 0002, under Section 00 83 00.00 which includes a revised material list such that the approved source that requires the Government to purchase the material has been deleted from the listing. Also, Note 3, which stated the Government would purchase the material, has been deleted.

(2) The State of Wisconsin DNR letter dated 10-14-09 indicates that the 16,000.00 CY of excess excavated material is to be placed in the Monarch Paving Pit.

Answer: This is addressed in Amendment 0002, which includes a revised bid schedule and Measurement and Payment Section that addresses excavation more thoroughly. The DNR letter states that the excess excavated material is to be placed at the Monarch Paving Pit or an approved alternate site. The bid schedule and Measurement and Payment Section now have an “Excavation” split bid unit price bid item for material excavated from the spot dikes. The split bid quantities are 10,500 CY and 3,100 CY for a total of 13,600 CY. Work includes excavation, backfill, and removal and proper disposal off site of excess excavated material. The Contractor is to determine how much excavated material is excess and therefore to be removed from the site.

There is also a “Contractor Haul Road” lump sum bid item for the Contractor’s haul road that covers excavation for rock placement and removal and proper off site disposal of excess excavated material. Since this is a lump sum bid item, it is the Contractor’s responsibility to determine how much excavation is required as well as how much material is to be removed and properly disposed of off site.

(3) Where is the pit located?

Answer: The Monarch Paving pit is located at the intersection of Pierce County Road K and State Highway 35, approximately 4 miles from spot dike J.

(4) The same letter addresses a change in the access roadway design to allow for the rock to be placed over the existing soils, hence no stripping. Can you clarify that this is the design criteria that we need to bid?

Answer: The contract drawings only show stripping for the minimum access trail, not over the entire haul road. It is the Contractor’s decision as to what to do for removal of soils for haul road construction outside of the minimum access trail section.

(5) Can someone give more thought to the erosion control specifications, Does the entire project need to have silt fence around it?

Answer: It is the Contractor’s responsibility to meet erosion control requirements spelled out in the specifications as well as the DNR’s permit.

(6) What is the USACE schedule for the project? How many working days?

Answer: The Notice to Proceed would be January 18, 2010 and the Completion date would be December 31, 2011. Approximately 713 working days.

(7) Should the detail 4 on sheet C – 301 show geotextile between the existing sheeting and the new sheeting?

Answer: The area where geotextile is to be placed does not include the area between the existing and new sheetpile.

(8) The riprap specification and the detail 4 on sheet C-301 indicates 24” riprap and 36” riprap. Generally, the size of the riprap and the depth of riprap are different-the depth is usually one and a half times the size. It would be difficult to place 24 inches of 24 inch riprap and achieve the desired results, the same would be true for the 36 inch riprap. Can you please clarify?

Answer: the two riprap section thickness have the same gradation, which is shown in section 35 31 19.00 13. The gradation is a standard one used by the Corps for riprap sections a minimum of 24” thick. Corps gradations typically have a maximum stone size that is slightly less than the gradation thickness. For example, for this gradation the maximum stone weight is 691 lbs. Based on ENG Form 4055 at the end of section 35 31

19.00 13 for a weight of 691 lbs and a specific gravity of approximately 2.65, this would correlate with a stone size of about 21”.

(9) The detail 4 on sheet C-31 shows backfill over the 24 inch riprap, does the 36 inch riprap get backfilled as well?

Answer: Yes it does. The riprap section upstream of the upstream sheetpile should be backfilled (including the 4” topsoil) to elevation 675 feet..

(10) I understand that the trail detail has changed with the amended drawings, do the new details govern or the Wisconsin DNR permit?

Answer: Amendment 0002 does not have a change to the trail detail. However, the bid schedule and Measurement and Payment section in the specifications will change so that there will be split bid unit price items for the minimum trail section for Aggregate Surface Material and Breaker Rock and a lump sum bid item for the Contractor Haul Road.