CONTRACTOR'S INQUIRY RESPONSES

December 11, 2001

CONTRACT NO. 04-012054
SFOBB-East, Roadway Embankment

 

The responses to contractors' inquiries, unless incorporated into a formal addenda to the contract, are not a part of the contract and are provided for the contractor's convenience only. In some instances, the question and answer may represent a summary of the matters discussed rather than a word-for-word recitation. The responses may be considered along with all other information furnished to prospective bidders for the purpose of bidding on the project. The availability or use of information provided in the responses to contractors' inquiries is not to be construed in any way as a waiver of the provisions of section 2-1.03 of the Standard Specifications or any other provision of the contract, the plans, Standard Specifications or Special Provisions, nor to excuse the contractor from full compliance with those contract requirements. Bidders are cautioned that subsequent responses or contract addenda may affect or vary a response previously given, and any such subsequent response or addenda should be taken into consideration when submitting a bid for the project. Inquiries submitted within seventy-two (72 ) hours of the bid opening date might not be addressed.

The Caltrans District 4 Office is located at 111 Grand Avenue, Oakland, CA 94612. Send Contractor Inquiries via email to the Tollbridge Duty Senior at Duty_Senior_Tollbridge_District04@dot.ca.gov. The mailing address is P.O. Box 23660, Oakland, CA 94623-0660. The Duty Senior's telephone number is (510) 286-5590. All inquiries must include the contract number.

Inquiries for 04-012054
Total Number of Inquiries:28
Inquiry
No.
Inquiry/Response

1.0

Are there x-sections available for this project? The information on the plans is inadequate to determine the earthwork quantities for this project. What information is available?

There are no cross sections for this project. Survey data is provided in Addendum #1 to produce the cross sections.

2.0

We have requested cross-sections & full size plan sheets from B.P.S. in Oakland, for above referenced project. To date they are telling us they have not received these files from Caltrans. When will these files be available to purchase from B.P.S.

There are no cross sections for this project. Please see Addendum #1 for Survey Data. Full size plan sheets are now available at Blue Print Services, phone (510)287-5485.

3.0

Is it possible to have a full size set of plans and cross sections available to contractors for take-off purposes?

Please see response to #2.

4.0

Section 10-1.46 Vertical Drains. Are there other ground improvement alternatives (i.e. vibro compaction, vibro stone columns, etc.,) that are acceptable in lieu of the specified vertical drains ?

The Geotechnical group had reviewed the other alternatives and came to the conclusion that the vertical drains is the best option for ground improvement under these site conditions. No other alternatives are allowed.

5.0

Reference sheet 33 of 48. The sketch shows MLLW Elev -0.51. We believe this is incorrect and it is also inconsistent with the MLLW elevation shown on sheet 3 of 48. Please clarify.

MLLW -0.85 as shown on sheet 3 of 48 is correct.

6.0

The purpose of the temporary geotextile tubes is unclear. Are the geotextile tubes being used to minimize wave action and scour in the work area or are the tubes intended to form a "watertight" barrier so the work area can be dewatered? The stage construction drawing, sheet 32 of 48 does not indicate that dewatering is mandatory. However, section 10-1.04, Non-Storm Water Discharges and Excavation Dewatering seem to imply that dewatering is anticipated. A response to this this question is paramount since the entire method of construction is affected by Caltrans' intent.

The purpose of the temporary geotextile tube is to minimize wave action and scour in the work area. Dewatering is not mandatory. , however, if the contractor deems it necessary, dewatering is allowed per section 10-1.04 Non-Storm Water Discharges of the Special Provisions.

7.0

Reference sheet 33 of 48. The upper elevation, MHHW 1.03, is shown just below the top of the temporary geotextile tube. This seems to imply that the tubes should be high enough to prevent flow over the top of the tubes. However, MHHW 1.03, is only the MEAN of the highest high tides. The highest observed water level, EHW, (from contract 04-012024 pg. 479) might be as much as 1.74. Please confirm the intent of the drawing.

The information shown on the drawing represents the estimated MHHW and MLLW of the project area. Should the contractor deem it necessary to consider the highest observed water level when ordering and installing the geotube, they may do so, so long as they comply with the Special Provisions.

8.0

In section 10-1.13, regarding the Temporary Geotextile tube, there was no information given about the size or circumference of the geotextile tube to be used. In the spec, it refers you to the plans for further information. After looking at the plans, I can not find any information relating to size of tube. Can you help point me in the right direction?

The contractor should determine elevation of the tube based on site conditions.

9.0

Is it possible to access a list of planholers via the caltrans website?

Please see List of Plan Holders at the following web address: http://www.dot.ca.gov/hq/esc/oe/project_status/afb.html

10.0

Reference the Special Provisions, Section 10-1.33 Earthwork, subsection, Materials. The special provisions state that embankment material shall consist of clean soil and shall conform to Sections 19-7.01 and 19-7.02 of the Standard Specifications.

We are concerned that clean soil is an inappropriate material for the tidal portion of the embankment (unless the area is completely dewatered). If the work area remains tidal, an embankment composed of clean soil will become saturated, unworkable and tend to wash away.

Is a minus 150mm crushed rock acceptable material for the lower ( say from Elev. 0.0 - +2.0 NGVD) portion of the embankment?

If not, is a minus 75mm crushed rock acceptable material for the lower portion of the embankment?

The special provisions require embankment materials composed of clean soil conforming to Sections 19-7.01 and 19-7.02 of the Standard Specifications with the additional requirements of a minimum R-value and certain Unified Soil Classification System (USCS) classification exclusions. Any proposed materials meeting these requirements are acceptable. All embankment materials must be placed and compacted to the specifications. Due to the tidal nature of the work, a temporary geotextile tube is utilized to minimize wave action and scour. At the discretion of the contractor and based upon on their proposed approach to work within the tidal areas, dewatering is also allowed (see responses to contractor inquiries #6, #7, and #8.)

11.0

Reference the Special Provisions, Sections 5-1.25, 26, 27 and 28. In order to comply with the restrictions or conditions of the various agencies, we need to obtain or see copies of the FINAL permits from the following agencies:

1. Regional Water Quality Control Board 2. U.S. Army Corp of Engineers 3. San Francisco Bay and Conservation Development Commission 4. U.S. Coast Guard

Are copies of the actual final permits available for viewing at the District 4 Office?

The following permits are available at the web site :
http://www.dot.ca.gov/hq/esc/tollbridge/index.html?SFOBB/EastSpan/012054/docs/Permits/Permit.html
1. The U.S. Army Corp of Engineers.
2. San Francisco Bay and Conservation Development Commission.
3. Regional Water Quality Control Board Water Certification.
4. Fish and Game.

The remaining permits will be posted on this web site once they are finalized.

12.0

We need to obtain copies of the Soil Borings and the "Materials Information" document for the above referenced contract. It is my understanding that these documents are available for viewing at the District 4 Office. However, we need copies of these documents to distribute to our potential specialty subcontractors, geotube and wick drain installers who are located in various cities around the country and cannot be expected to fly to Oakland to view these documents. Please let me know if we can visit your office and obtain copies there or if you will be furnishing these documents to all plan holders.

The original bid package included a CD titled "Oakland Touchdown - Geotechnical Fill" Information Handout. Please refer to that CD.

13.0

On sheets 2, 3, & 9 of 48 the MLLW elevation is -0.85. On sheet 33 of 48 the MLLW is -0.51. Is sheet 33 wrong?

Please see response to inquiry #5.

14.0

On sheet 33 of 48 the plans show the bottom of the rock dike 102m +/- wide. What is the correct width?

Please bid according to plans and specifications.

15.0

On sheets 2, 3, & 9 , does the plans show one or two layers of Geotextile Filter Fabric to be installed underneath the Class 3 Permeable (RSP Bedding)?

One layer.

16.0

On sheets 2,3, & 9 of 48, the plans show the bottom of the RSP Toe Excavation to be -2.3 elevation. On sheet 26 of 48 the plan shows the bottom of the RSP Toe Excavation to be -5.8 elevation on drainage system No. 7. Is one of these drawings incorrect?

Note: If page 26 is correct, the additional depth would put the temporary geotextile tube some 15 to 20 feet further out. Will this encroach the ESA limit?

The RSP detail on drainage plans is shown for clarity, however it is not to scale. Refer to the dimensions shown on the Construction Detail sheets.

17.0

Are there cross sections available for this project.

No. Please see Response # 1.

18.0

Are there borings available in the vicinity of the vertical and wick drains and in the designated area for fill for temporary tube?

Yes. Please see Respone #12.

19.0

Is the Temporary Geotextile Tube intended to minimize wave action in the work area or is the tube intended to form a dewatering barrier?

Please see Response #6.

20.0

With reference to the Temporary Geotextile Tube, I could not find any information on what size or circumference is required. Is there any additional information on this required tube?

Please see Response #7.

21.0

Reference to Imported Borrow, which ultimately the specifications require the material to consist of clean soil and shall conform to the standard specifications. I have a concern that the clean soil will be inappropriate material for fill within the tidal zone and become too saturated to work. Could a rocky type material be utilized within the tidal zone for embankment?

Please see Response #10.

22.0

We are suppliers of fabrics and erosion products. In reviewing the specs. for the above mentioned project, we notice the specification for Item # 32 EROSION CONTROL (NETTING) does not appear to be here. Will the spec come out on an addendum?

Please bid according to the Plans, Specifcations and Estimate.

23.0

In reference to Addendum No. 1 dated November 30, 2001:

(There isn't any page number to refer to so I will say it is the third page from the end)

Question: "The geotextile tube" - Is this a requirement for this job or can we use another method such as sheet piling for water control?

Please bid according to the plans and specifications. Changes may be proposed by the Contractor after award.

24.0

We are planning to bid on the above contract as a prime contractor.  The contract specifications refer to various permits that will apply to this contract.   J. E. McAmis, Inc. respectfully requests copies of the following permits or licenses obtained for this contract:

1) San Francisco Bay Regional Water Quality Control Board 2) U. S. Army Corps of Engineers (ACOE) 3) San Francisco Bay Conservation Development Commission (BCDC) 4) United States Coast Guard 5) National Marine Fisheries Serivce (NMFS) 6) US Fish and Wildlife Service (USFWS) 7) California Regional Water Quality Control Board

Please see Response # 11. The NMFS and USFWS permits were included in Addendum #1 (Information Handout CD1).

25.0

Reference is made to Bid Item 29, Roadway Excavation (Hazardous), and Section 10-1.33 of the Special Provisions for the above referenced contract, and the attached Caltrans memorandum dated December 4, 2001. Please advise if the subject memorandum applies to the Roadway Excavation (Hazardous) work to be performed on the subject contract.

The memorandum that is referred to is not part of the bid package for this project.

26.0

The 180 working day contract duration appears to be unrealistic.  The wick/vertical drain subcontractors are talking about 60 working days with three rigs working.  But the big problem is the restriction of the rate of embankment required by 10-1.33.  The minimum embankment time for the work above +1.5 meters elevation is 15 weeks (say 75 working days).  As a consequence there does not appear to be enough time remaining for the approval process and the substantial amount of remaining work.

Please bid according to the plans and specifications.

27.0

This Caltrans job has a bid item # 32 Erosion Control Netting but there are no corresponding specifications as to which netting to use. Would you please check this and e-mail back the correct netting to use on this job? Thank you.

Please bid according to the plans and specifications.

28.0

Reference plan sheet 32 of 48. Stage 3 states, "Place vertical drains and geotextile filter fabric". Stage 4 states, " Place Cl 3 permeable material blanket, etc". Is it possible to install the lower geotextile filter fabric and the Cl 3 permeable material blanket before installing the vertical drains? This will provide a .8 meter thick platform for the equipment to walk on.

No, this will compromise the function of the filter fabric.