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DATE: August 26, 2011 ADDENDUM NUMBER: 2 MODIFYING: Specifications No. 1614 PROJECT: Colorado River Aqueduct Transition Structures and Manhole Structures

Covers Replacement BID TIME AND DATE: 2:00 p.m., September 7, 2011 FROM: THE METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA

700 North Alameda Street, Third Floor Los Angeles, California 90012 (213) 217-6515

TO: All prospective bidders This addendum forms a part of the contract documents. Use Specifications No. 1614 as originally issued to submit bids, in conjunction with this addendum, and acknowledge receipt of this addendum by completing Item 4 in Document 00420, “Bidder's General Information,” in the specifications. Failure to acknowledge this addendum will render a bid non-responsive and the bid will be rejected. This addendum consists of 6 pages of text, 1 page of attached document, and 13 sheets of 11" x 17" drawings. CHANGES TO BIDDING REQUIREMENTS

1. Change the time and date for the opening of the bids from 2:00 p.m., September 1, 2011 to 2:00 p.m., September 7, 2011

CHANGES TO SPECIFICATIONS:

2. In Section 01010, “Summary of Work, delete Paragraph 1.01B, and replace with the following:

B. The project consists of removing and disposing of existing steel plate transition covers, pre-cast concrete and plate steel manhole covers, and metal support beams along the Colorado River Aqueduct (CRA) between Mile Marker 104.96 and Mile Marker 232.15; replacing 56 transition covers with new steel covers, and 75 manhole covers with new pre-cast concrete covers, repairing 64 manhole structures, and all other appurtenant work as specified and shown on the drawings

3. Delete Section 01050, “Construction Surveying,” dated December 17, 2008, and replace with attached Section 01050, dated August 23, 2011.

4. In Section 01550, “Access, Parking, and Traffic,” subparagraph 1.06A.3.b, change the phrase “once per week” to read: “once per month”.

5. In Section 03100, “Concrete Formwork,” at the end of Paragraph 1.02B, add the following Paragraph 1.02C and subparagraphs:

C. Working Drawings

1. Drawings showing the general design, details, and dimensions of the forms proposed for the structures shall be submitted for review not less than 30 days before fabrication of forms. The size, number, and location of cleanouts at the bottom of forms shall also be shown. Drawings shall be coordinated with drawings required by Section 03210 and Section 03300.

2. Panel sizes and panel joint locations in Class 1 and Class 2 forms.

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3. Method of support for welded steel pipe, fabricated fittings, and conduits where encasement in concrete is required.

6. In Section 03300, “Cast-in-Place Concrete, “subparagraph 1.02A.1, delete the third sentence and replace by the following sentences:

All concrete and ready-mixed grout supplied to the project shall be from a single supplier approved by Metropolitan. Maximum of two different batch plants from the same supplier may be used to supply concrete and ready-mix grout.

7. In Section 03300, delete Paragraph 1.02B, and replace with the following:

B. Not used

8. In Section 03300, at the end of Paragraph 2.06E, add the following Paragraph 2.06F:

F. Set retarding admixtures, if used, shall be submitted for approval by Metropolitan.

9. In Section 03400, “Structural and Architectural Precast Concrete,” delete subparagraph 1.04C.3, and replace with the following:

3. Following acceptance of the samples, the Contractor shall fabricate one full-scale mockup and deliver to the Engineer’s field office.

10. In Section 09900, Table 1, delete System CS-2.

CHANGES TO DRAWINGS:

11. The following drawings have been revised, as shown on the prints of the attached drawings. These drawings as revised shall be controlling for the purposes of the required work in lieu of the drawings previously issued. The changes made on each drawing are indicated in the revision block on each drawing.

Reference No. Sheet No. Drawing No. Revision No.

1. G-2 B-137530 1

2. G-3 B-137531 1

3. G-4 B-137532 1

4. G-5 B-137533 1

5. G-6 B-137534 1

6. G-7 B-137535 1

7. G-8 B-137536 1

8. G-9 B-137537 1

9. C-4 B-137542 1

10. S-10 B-137560 1

11. S-11 B-137561 1

12. S-12 B-137562 1

12. The following new drawing has been added to the contract drawings. A print of the new drawing is attached.

Reference No. Sheet No. Drawing No. Description

1. S-15 B-137566 Manhole Structure Repair; Type 5 - Plan, Sections and Details

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QUESTIONS AND CLARIFICATIONS:

Requests for clarification of details on the drawings or of provisions of the specifications have been identified. The questions with the appropriate Metropolitan responses are as follows:

(1) Question: Per Section 01550 – Access, Parking, and Traffic, subparagraph 1.06A.3.b, it is stated the Contractor shall provide a sweeper to maintain existing plant roads once per week, or more frequently if necessary. The only traffic expected on plant roads shall be the access to the Contractor’s work and storage area as noted on the plan drawings; which would be limited to Engineer on site staff, pick-up trucks and materials deliveries. Please clarify if based upon this type of traffic, if a sweeper will be required for the duration of time in which such storage area is used, or if this requirement shall be waived by the Owner.

Answer: In this addendum the sweeping requirements are changed to monthly sweeping.

(2) Question: In Section 03300, subparagraph1.02A.1, it is stated only 1 source for the supply of concrete and ready-mixed grout shall be approved; furthermore it is stated all concrete and ready-mixed grout supplied to the project (regardless of Contractor or subcontractor) shall originate from the approved single facility. Considering there is a span of 127 miles between the first and last structures, will this requirement be waived to facilitate plants in closer proximity to each of the applicable structures?

Answer: In this addendum in Section 03300, subparagraph 1.02A.1, we have changed the supplier and source requirements.

(3) Question: In Section 03300, Paragraph1.02B, it is stated that composite concrete placement drawings shall be submitted, each drawing showing only 1 placement. Please clarify that all of manhole structure repairs (65 total structures) will require spalled concrete repair drawings regardless of the type of detail specified.

Answer: In this addendum, this requirement is removed.

(4) Question: In Section 03300, Article 2.06, several admixtures which shall be acceptable are defined. However please clarify if a set retarding admixture shall also be acceptable due to the extended distance of the approved batch plant to the specific project location(s).

Answer: In this addendum, the requirement for set retarding admixture has been added.

(5) Question: In Section 03300, Article 3.08, it is unclear what type of finish shall be required for the spalled concrete repair, Details 2 and 4. Please clarify if an Architectural Finish per Article 3.09 or finishing of unformed surfaces per Article 3.10 shall be required for the repair work at such manhole structures.

Answer: For the spalled concrete repairs shown on Details 2 and 4 on Sheet S-12, the type of finish shall be in accordance with Article 3.09, Architectural Finish.

(6) Question: In Section 03400, subparagraph 1.04B.2, it is stated concrete producing facilities shall be in accordance with Section 03300. Please clarify if Section 03300, 1.02.A.1 applies, and only a single concrete producing facility shall be used for both cast-in-place concrete applications, as well the precast concrete manhole structure covers?

Answer: No, the concrete producing facilities for the pre-cast concrete may be different than the source used for the cast-in-place concrete.

(7) Question: In Section 03400, subparagraph 1.04C.3, it is stated the Contractor shall fabricate the full-scale mockups upon acceptance of the two 18” square samples. Please clarify the quantity of full-scale mockups which will be required. Additionally, please clarify if the approval of the mockups shall be completed at the precast manufacturing plant, or if the full-scale mockups will be delivered to the Contractor’s work and storage area/Engineers field office for Engineer approval.

Answer: In this addendum, we have revised subparagraph 1.04C.3 to submit one full-scale mock-up of the precast units and its delivery to the Engineer’s Field Office.

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(8) Question: Per Section 05120 – Structural Steel, please confirm that all Type 1, 3 and 4 transition structure covers shall conform to this specification section as opposed to Section 05500 – Miscellaneous Metals. Furthermore, please clarify if any other technical specification sections not listed under 1.01 References shall be referenced and/or required to be in compliance with regarding the fabrication of such covers.

Answer: All transition structure covers shall be fabricated and furnished in accordance with Section 05120. Article 1.01 of Section 05120 does not reference other Specifications Sections; however, any other Section that applies shall be used.

(9) Question: General Note 23 on Sheet G-3 states that prior to the start of fabrication the Contractor shall field verify the dimensions, including the ‘diagonal dimensions’ of each transition and manhole structure cover, and then prepare fabrication drawings accordingly. Furthermore, per Sheet S-1, Note 10, it is stated clearances shall be ½” minimum and 1” maximum typical at all sides. Achieving the clearance tolerance of ½”-1” between the perimeter of the new transition cover and the existing concrete structure may not be possible if the concrete structure is bowed in any way or not plumb from one point to the next. Please clarify if the clearance tolerances will be waived to match the existing concrete structure.

Answer: If a concrete transition structure has a curved wall, then the transition cover shall be fabricated with a curve to match the wall. The intent is to fabricate a cover to match the structure. The clearance tolerances will not be waived.

(10) Question: On Sheet S-4, Note 8, it is stated the new covers shall be hot-dipped galvanized in accordance with Section 05500. It is also stated that the covers shall have an overall flatness tolerance of ~1/8” after galvanizing and shall be straightened as required. We understand that AISC, ASME and ASTM standards recommend against certain steel article combinations when hot dip galvanizing due to the high potential of warpage and distortion, please clarify if these standards were taken into consideration regarding the materials for construction of the transition covers. Also, please clarify if the contractor shall assume that all covers will require straightening after galvanizing to meet the 1/8” requirement as well the fabrication tolerances as noted within Section 05120, 2.08 per ASTM A6.

Answer: The standards listed were taken into consideration. The amount of warpage that may occur in the transition covers will be due to the Contractor’s means and methods of fabrication, and Metropolitan has no way of knowing whether all covers will require straightening or not.

(11) Question: Section 05500, Paragraph 3.02A, it is stated that galvanized surfaces damaged during fabrication, shipping, erection or any time prior to the acceptance of the work shall be prepared and recoated per one of the following methods in the specification section as listed. In addition to the hot-dipped process, as well the sprayed zinc (metalizing) procedures as listed, please advise if ZRC zero or cold galvanizing spray will be acceptable. Additionally, please advise if these galvanized repair procedures can be performed on site (with the exception of the hot-dipped process). Lastly, please confirm if applying a lead based product (i.e. lead based hot stick) is approved by the California EPA to surfaces over drinking water.

Answer: The use of ZRC zero or a cold galvanizing spray will not be considered an acceptable repair for damaged galvanized surfaces. The repair of damaged galvanized surfaces can be performed on the site. The use of a lead-based product to repair damaged galvanized surfaces is unacceptable.

(12) Question: In Section 09900, Table 1, it is noted for Architectural Carbon Steel, system number CS-2 shall be utilized on the exterior bottom of selected transition cover plates as noted per drawings. However per Sheet S-4, Note 10, states the outside face of all HSS 9x3 members, and the bottom surface of covers shall be epoxy coated in accordance with Section 09900. Please clarify if this note is what system

Answer: In this addendum System No. CS-2 has been deleted. Note 10 on Sheet S-4 shall apply.

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(13) Question: Are the transition structure covers included in Section 05120 “Structural Steel” or Section 05500 “Miscellaneous Metal”?

Answer: All transition structure covers shall be fabricated and furnished in accordance with Section 05120. (14) Question: Ref. Sheet S3-1, Detail 1 “Anchor Bolt Detail”; We cannot find this detail called-out on any

drawings. Please advise. Answer: This is a standard drawing. Detail 1 on Sheet S3-1 of the drawings does not apply this project.

(15) Question: Section 09900 “Painting”; We assume that all surfaces of the transition and manhole covers are to be galvanized followed by the underside being coated (shop or field) with Table 1 System CS-1. No coating of the top surfaces other than galvanizing is required. Please confirm.

Answer: No coating of the top surface of the transition covers is required, except the portion of the tube steel shown in Section A on Sheet S-4 of the drawings.

(16) Question: When is the anticipated date of CRA Shutdown? Is there a standard each year, i.e. Start Month – Finish Month?

Answer: The current start date of the CRA Shutdown in 2012 is February 28, 2012. The start date of the CRA Shutdown in 2013 is not set yet. In accordance with Section 01010, Article 1.05A, the CRA Shutdown is “during February / March every year.”

(17) Question: (What is the) extent of dust control requirements beyond each manhole or structure?

Answer: In accordance with Sections 01060, 01065, and 01500, the Contractor shall control dust in all unpaved areas utilized by the contractor, including but not limited to, access roads, laydown areas, work and storage areas, work areas and work limits,

(18) Question: How many Pre-Cast concrete manhole structure covers and how many Pre-Cast concrete Transition structure covers in this project?

Answer: For this project, there are two manholes (at Mile Markers 169.33 and 169.85) with pre-cast concrete covers. All transition structures covers are steel; there are no pre-cast concrete transition covers that are part of this project.

(19) Question: The tolerances that are stated for the transition covers:

- +1/8” flatness after galvanizing/Epoxy

- 1/2” to 1” Outside at all sides

- ½” Between each section

Based on the physical dimensions provided, the section should be flat. In looking at the existing concrete ledge it rests on, it appears that this surface is not level or has settled. Is that a concern once the plates are installed and may not lay perfectly flat?

Answer: The new steel transition covers shall be flat as specified. Besides the work to remove the existing bearing plates on the existing concrete ledge, there is no other work specified on the concrete ledge.

(20) Question: In Section 01060, 4 & 5, are both the transition covers and precast manholes to be hauled/disposed of as hazardous, or just the transition covers. The specs state it both ways.

Answer: The existing steel transitions covers and steel manhole covers are considered hazardous waste as specified. The existing precast manhole covers are not considered hazardous waste.

(21) Question: How long will the employee orientation meeting take?

Answer: As stated in Section 01065, Article 1.10A.2, the desert tortoise awareness program consists of a one-hour training course.

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(22) Question: The information provided does not show how many locations we will cross the existing aqueduct. We need that number to determine how many times we will need to protect the system (i.e. heavy loads)?

Answer: The Contractor shall be responsible for determining how many locations the aqueduct will need to be crossed.

(23) Question: In Section 01060 -4 & 5, C, you have a concern about the plates collapsing during lifting. We understand you want no debris or material contaminating the system. Could you provide a few methods previously used?

Answer: Section 01060, Paragraph 1.12C provides several methods to be used for the rigging and removal of the existing steel transition covers.

(24) Question: What are the weights of the transition covers? We need that information to determine our pick loads.

Answer: The total weight of the transition covers vary between 4,000 to 8,000 pounds.

(25) Question: Contract Drawings Sheet S-11 shows one set of outside dimensions and one precast cover edge detail. The reference drawing for a typical 3’-6” x 9’-6” manhole shows a two piece metal cover. During the job walk, at least two types (metal and precast) manhole covers were observed. Additionally only a small number of manholes to have covers replaced were included on the job walk tour. Please provide complete information detailing location, existing cover type and new cover edge detail for all manholes requiring cover replacement.

Answer: The location of the existing manhole covers are shown on Sheets G-4 thru G-10 and in the table on sheet S-10. As stated in the response to Question No. 19, for this project, there are two manholes (at Mile Markers 169.33 and 169.85) with pre-cast concrete covers. All other existing manhole covers are metal. The new cover edge detail is as shown on Sheet S-11 of the drawings.

(26) Question: Section 01050, Paragraph 1.03A states that The engineer will establish and set a system of primary control to be used for establishing lines and grades required for the work.

How close to the layout areas will the Primary control be? Will the Engineer establish primary control points (2) near each layout area suitable for the contractor to utilize a robotic survey system for staking the layout areas or is it the Contractor’s responsibility to establish latitude and longitude at the layout areas with static GPS observations or other survey methods?

Answer: Please see the changes in this addendum. Section 01050 is replaced with a new section. Metropolitan will not establish primary control. The Contractor will not have to establish secondary control.

The Contractor shall be responsible for staking the control points for the additional laydown areas as shown in Appendix “A,” of Section 01500, by static GPS observations or other survey methods.

END OF ADDENDUM

August 23, 2011 01050-1 1614 (construction contract Addendum 2

SECTION 01050 CONSTRUCTION SURVEYING

PART 1 GENERAL

1.01 RESPONSIBILITY FOR CONSTRUCTION SURVEYS

A. The Contractor shall provide all other survey services required for the work, including establishing construction control, setting of stakes and monuments, and performing surveys needed for restoration of public and private improvements that have been damaged, destroyed, or relocated by the Contractor.

B. The Contractor shall be responsible for staking the control points for the additional laydown areas as shown in Appendix “A,” of Section 01500.

1.02 ACCURACY OF SURVEYS

A. Instruments shall be accurate and shall be subject to inspection by the Engineer to verify proper operation.

1. Electronic distance measuring (EDM) instruments used by the Contractor on the project shall be checked for calibration once per month, minimum, on an established baseline approved by the Engineer. Calibration results shall be kept in a logbook, available for the Engineer's review, showing the date and distances measured on the baseline. An EDM instrument shall not be used if it does not meet the minimum accuracy published by the manufacturer.

2. Defective instruments shall be promptly replaced, repaired, or adjusted to operate within the tolerances specified by the instrument manufacturer.

B. The Contractor's measurements of line, grade, and distance will be subject to checking by the Engineer. Measurements that do not comply with the accuracy required by this section shall immediately be corrected by the Contractor.

1. The Contractor shall give the Engineer assistance and provide forms, ladders, spikes, nails, string lines, and utilities that may be required by the Engineer and shall adjust construction operations as necessary to enable the Engineer to perform this part of the survey work.

1.03 PROTECTION OF MONUMENTS, STAKES, AND MARKS

A. Whenever any monuments, other than Metropolitan’s boundary monuments, that control the location of subdivisions, tracts, boundaries, roads, streets, or highways, or provide horizontal or vertical survey control are disturbed during construction, the Contractor shall follow the procedures set forth in Section 8771 of the California Business and Professions Code and as specified below. The Contractor shall provide to the Engineer copies of all documentation submitted to the applicable County.

B. Metropolitan has set historical benchmarks at some of the structures associated with this project. These benchmarks and their elevations will need to be perpetuated. Metropolitan’s Field Survey Team shall remove the markers prior to the start of construction.

C. The Contractor shall preserve and protect all survey monuments and related marks within a Metropolitan facility. When removal is necessary, the Contractor shall accurately reference the monuments or related marks subject to the approval of the Engineer.

1. Primary or secondary control monuments shall be reset by the Contractor as soon as the work requiring removal is complete. Alternatively, other control monuments may be set so as to reestablish the control network.

2. The position of monuments, control points, or other marks that are subject to movement due to construction equipment or other forces shall be rechecked at regular intervals, but not less than monthly.

D. The Contractor shall give the Engineer a notice of 2 working days prior to any necessary disturbance of a Metropolitan property boundary monument. If the Contractor disturbs a Metropolitan property boundary monument of record, the Contractor shall reimburse Metropolitan for resetting the monument.

PART 2 PRODUCTS (NOT USED)

PART 3 EXECUTION (NOT USED)

END OF SECTION