Amendment 0008.pdf

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.

15A. NAME AND TITLE OF SIGNER (Type or print)

30-105-04EXCEPTION TO SF 30

APPROVED BY OIRM 11-84

STANDARD FORM 30 (Rev. 10-83) Prescribed by GSA

FAR (48 CFR) 53.243

This amendment is issued to provide response(s) to Requests for Information. All other terms and conditions remain unchanged.

1. CONTRACT ID CODE PAGE OF PAGES

1 4

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)

16C. DATE SIGNED

BY

16B. UNITED STATES OF AMERICA15C. DATE SIGNED15B. CONTRACTOR/OFFEROR

(Signature of Contracting Officer)(Signature of person authorized to sign)

8. NAME AND ADDRESS OF CONTRACTOR (No., Street , County, State and Zip Code) X W912WJ21B0015

X 9B. DATED (SEE ITEM 11)

28-Jul-2021

10B. DATED (SEE ITEM 13)

9A. AMENDMENT OF SOLICITATION NO.

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

X The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offer is extended, X is not extended.

Offer must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended by one of the following methods:

(a) By completing Items 8 and 15, and returning 1 copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted;

or (c) By separate letter or telegram which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN

REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

12. ACCOUNTING AND APPROPRIATION DATA (If required)

13. THIS ITEM APPLIES ONLY TO MODIFICATIONS OF CONTRACTS/ORDERS.

IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE

CONTRACT ORDER NO. IN ITEM 10A.

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation date, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(B).

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

E. IMPORTANT: Contractor is not, is required to sign this document and return copies to the issuing office.

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

10A. MOD. OF CONTRACT/ORDER NO.

U0008

2. AMENDMENT/MODIFICATION NO. 5. PROJECT NO.(If applicable)

6. ISSUED BY

3. EFFECTIVE DATE

09-Sep-2021

CODE

U S ARMY ENGR DISTRICT, NEW ENGLAND

696 VIRGINIA RD

CONCORD MA 01742-2751

W912WJ 7. ADMINISTERED BY (If other than item 6)

4. REQUISITION/PURCHASE REQ. NO.

CODE

See Item 6

FACILITY CODECODE

EMAIL:TEL:

W912WJ21B0015

SECTION SF 30 BLOCK 14 CONTINUATION PAGE

SUMMARY OF CHANGES

SECTION 00100 - BIDDING SCHEDULE/INSTRUCTIONS TO BIDDERS

The following have been added by full text:

AMEND 0008

QUESTION:

There is a significant issue remaining in the specifications for the referenced project similar to what was in the original specs for the Boston Harbor deepening project, and which was ultimately resolved by an amendment in the wording of the project specifications. The recently cancelled USACE project at Ogdensburg Harbor, NY suffered from the same problem. Not resolving this matter may result in an unconstructable set of prescribed blasting parameters.

Specifications Section 35 30 00 Underwater Drilling & Confined Blasting Part 1.7.3.1.f. – Test Blasting

On page 13, states that ‘A minimum of three shots are required for the Test Blasting’. The referenced part of the specifications continue to describe the requirements for the first three test blasts, including the maximum explosives charge weight (6 lbs, 12 lbs and 25 lbs) per delay and maximum number of holes per test blast (3, 9 and any number of holes).

Depending on the location of the Test Blast and the Contractor means and methods, the minimum explosives weight per hole would have to be more than 35 lbs and perhaps as much as 150 lbs, to efficiently fragment the bedrock and provide real-world test conditions for initial blasting, blast monitoring and dredging productivity. The stated test blast requirements are not realistic to implement.

We suggest striking the entire third paragraph on page 10: ‘Limit the first test shot to three drilled holes in a single row and have a maximum charge weight per delay of 6 pounds of explosives materials … as long as the preceding test shot was completely satisfactorily.’ The remaining text of Part 1.9.2 will still serve the purpose of gradually increasing the pounds of explosives per delay during test blasting and evaluating the resulting blast monitoring parameters and dredging conditions.

Related to this matter, the following question:

The implication of the language on page 13 in the abovementioned part of the blasting specifications, is that the explosives weight for production blasting is limited to 25 lbs per 25-ms delay: ‘The third test and other production shot patterns may use any number of drilled holes and a maximum charge weight per delay of double the pounds of explosives and blasting agents per 25-ms delay to the limit of 25 pounds According to guidance from paragraph 7.11 c. (2) on page 7-30 of the USACE Engineering Manual EM 1110-2-3800 (2018), and our own experience in underwater blasting of bedrock similar to what is required for this project, the powder factor necessary to efficiently fracture the rock for subsequent mechanical excavation is about 2 pounds of explosives per cubic yard of material blasted.

The USACE safety manual EM 385-1-1 (2014) specifies in paragraph 29.J.07 (a) on page 29-16 that ‘the distance between a loaded hole and one being drilled shall be 1/3 the depth of the hole, with a minimum of 8 ft (2.4 m) between the loaded hole and the one being drilled.’

When one applies the blast design formulas as described in paragraph 7.11 d. on page 7-30 to 7-35 of EM 1110-2-3800, and incorporate the 8 ft minimum distance between holes, the result is that an explosive material with a diameter of at least 3.5” must be selected to achieve the necessary powder factor. The typical density for explosives suitable for underwater blasting of bedrock is about 1.25 g/cc.

This means that an explosives charge measuring one foot in length will weigh about 5.2 pounds.

The most optimistic case for depth of rock cut is where the rock is at grade. In order to efficiently break the rock between holes which are 8 foot apart and not leave high spots between holes after blasting, each blast hole must be drilled between 9 and 12 foot deeper than the overdredge elevation. The top 2 foot or so of each blast hole will be filled with inert stemming material, which means that 7 to 10 foot of the blast hole must be filled with explosives to achieve the target powder factor. Using the 5.2 lbs per foot from the above paragraph, this equates to an explosives charge in each hole of 36.4 to 52.0 lbs. This is an underestimation of the actual amount of explosives needed, because this example is for rock at grade.

In addition to the above, most contractors would want to optimize the distance between blast holes and match the fragmentation of the blasted muck pile with the size dredging equipment they selected for the project. In practice, this means that blast holes may be drilled up to 14 feet apart. Because the necessary powder factor remains 2.0 pounds per cubic yard of rock blasted, the only way to provide sufficient energy to break the rock, is to increase the diameter of the explosives charge, sometimes to as large as

5.0 inches. A 5.0-inch diameter charge implies an explosives charge weight of 10.6 lbs per foot.

The above illustrates that the limit of 25 pounds of explosives per delay directed by the USACE may result in an unconstructable project.

We therefore respectfully request that the government only provides the performance criteria for the blasting work (ground vibrations in PPV, peak underwater overpressure in psi and other criteria), and let the contractor design and implement the drilling and blasting work in a manner protective of the public, nearby structures and marine life, and in accordance with the stated performance criteria and other regulatory requirements which may apply. Therefore, we request that the government considers removing the language from the description of the (test) blast program which directs the contractor to limit the maximum amount of explosives per delay to 25 pounds.

GOVERNMENT RESPONSE: See Specification Changes below.

SPECIFICATION CHANGES

1. Amend Section 35 30 00 UNDERWATER DRILLING AND CONFINED BLASTING as follows:

Under subpart 1.7.3.1 titled “Test Blast Plan” remove subparagraphs 1.7.3.1d, 1.7.3.1e, and 1.7.3.1f in their entirety and replace them with the following subparagraphs:

d. Use the type of explosives and firing systems that adhere to all applicable codes and regulations including, but not limited to, those cited in subpart “PERFORMANCE REQUIREMENTS”. A minimum of three shots are required for the Test Blasting. Complete a Shot Plan, which is referenced in Subpart “Shot Plan”, for every shot, including these test blasts. Increase the number of shot holes loaded and the maximum charge weight per delay of subsequent test and production shot patterns only if the early shot pattern was apparently successful. An apparently successful shot pattern is defined as a properly fired pattern that has seemed to have been effective prior to spoil excavation and has remained below both the maximum and peak particle velocity value, as prescribed in Subpart “Vibration Control”, of this specification section.

e. For the next immediate shot pattern, use a smaller number of loaded drill holes and a smaller maximum charge weight per delay, if the prior shot pattern had a rifling plume or underestimated the recorded, peak particle velocity by 25% at any monitoring location or had any type of misfire, damage or injury or accident.

f. Limit the first test shot to three drilled shot holes in a single row and an initial charge weight per 25 m/s delay. Limit the second test shot to nine holes in a shot pattern of the Contractor's choosing and to a maximum charge weight per delay of double the first shot’s maximum charge weight per delay, as long as the first test shot was completely satisfactory. The third test shot may use any number of drilled holes and a maximum charge weight per delay of double the second shot's maximum charge weight per delay, as long as the preceding test shot was completely satisfactory.