HUSSEY GAY BELL SAVANNAH, GEORGIA

Transcription

1 HUSSEY GAY BELL SAVANNAH, GEORGIA ADDENDUM NO. 3 TO THE CONTRACT DOCUMENTS AND TECHNICAL SPECIFICATIONS FOR 2.4 MGD CHAPIN WASTEWATER TREATMENT PLANT FOR TOWN OF CHAPIN, SOUTH CAROLINA AUGUST All Bidders and other interested parties are hereby notified of the following additions and/or revisions to the Plans and Specifications of the referenced project. RECEIPT OF THIS ADDENDUM MUST BE ACKNOWLEDGED ON THE BID PROPOSAL. *************************************************************************** PLANS 1. Please replace Sheet G5.6 with Revised G5.6 Addendum No. 3 Revisions Please see attached MD1.1 for clarity in reference to Question No Please add Yard Hydrant Detail 4. Please add Inside Drop Manhole Detail

2 PROJECT CLARIFICATIONS 1. DIGESTER DECANT PIPING: Drawing M6.0 is showing the piping layout for the Digester. Where section A cuts through the Digester, where the stairs are shown, we see Decant ( TYP ) called out and three pipe drawn in light weight lines. Looking at section view A on M6.1, we see the Decant piping on the outside of the Digester. Looking back at the plan view layout, we do not see a line extending away from the Digester. Also looking at the yard piping drawings G7.1 and G7.2, these drawings do not show the 8 line. Please review and clarify the Decant line piping. The plan view on M6.1 is accurate. The Town desires to have three independent decant outlets for the digester. Each outlet is set at a different height. Each decant outlet pipe has a plug valve for isolation for the main header. Each decant outlet pipe is offset both vertical and horizontally to allow for operation of the plug valve. The digester decant will need to be conveyed to MH#5. Please connect the decant line to the digester drain line after the plug valve using (1) 8x8 wye, (1) 8 45 bed and approximately 200 LF of 8 PVC pipe. 2. DIGESTER DECANT PIPING: Drawing M6.1 is showing the Decant piping on the outside of the Digester. Looking at the elevation view, we see the callout for (3) 8 PV with handwheel and SS chain operators. These are shown along the line of the vertical pipe going down into the ground. The way they are drawn, with light weight lines, it appears that they are behind the vertical pipe. There is also a callout for an 8 TEE ( TYP.). Looking above the elevation view, we see the plan view layout. This view is showing three plug valves in the pipe that comes out of the side of the Digester, before the pipe turn and extend over to the vertical decant pipe. We need some clarification on the quantity of valves to be provided at this location. The piping drawn appears to be showing six ( 6 ) plug valves. Please review and clarify the plug valves in the decant piping. Only (3) 8 plug valves are required. The three additional valves shown in Decant Details, A/M6.0 should not be visible in this section. 3. DIGESTER DECANT PIPING: Drawing M6.1 is showing the Decant piping on the outside of the Digester. We see the pipe penetrating the Digester tank wall. There is no indication for the type of penetration that is desired. Can wall sleeves and link seals be used at this location? Do you want wall pipe to be provided? Please review and clarify the penetrations in the Digester wall. Please use link seals with 304 stainless steel hardware at the three (3) 8 decant outlet connections. 4. RAS / WAS PUMP PAD: Drawing M10.0 is showing the layout for the three RAS / WAS pumps. We noticed that the discharge piping is drawn with a flanged 90 bend fitting above the pumps and then a valve is drawn. Then there is either a

3 flanged 90 bend fitting or a flanged tee fitting. Looking in the section B, the discharge piping has a callout at the valve stating 12 check valve and 12 plug valve. We take it that you have intended for the symbol for the plug to represent a plug valve and a check valve. Since this would mean that approximately another 12 has to be added to the discharge piping. We are wondering how that will affect the concrete pad the pumps and piping where they are installed. Does the pad need to be widened? Please review and clarify this pump pad and the piping. Please revise the pad width from 10 to 14 to accommodate the additional length from the valves. 5. SEPTAGE RECEIVING STATION: Drawing M1.3 is showing the Septage Receiving Station. We see a pipe between the Hauler Connection unit and the Septage Receiving unit in section A A. The note indicates that the contractor is to provide the pipe. There is no indication as to what material to use for the pipe. It appears to be drawn with possibly welded joints. Is the pipe to be PVC or maybe stainless steel? Please review and clarify the pipe between the two units. The piping is to be ductile iron or 304 stainless steel. 6. AERATION BASIN DIMENSIONS: Drawing M2.0 is showing the layout of the Aeration Basin. The plan view layout is indicating that it is drawn to a 1 /16 scale. Looking on the left side of the layout we see a dimension indicated, where the Section A / M2.1 symbol is located. This dimension is 8 1. Looking at the two surface aerators No - 1A and 1B, we see a dimension given between the two units. This dimension is We believe that these are in error. We have scaled the 8 Force Main pipe on the Aeration Basin. The branch line for the two plug valves, V201 and V202, scales to be 12 0 in the plan view. Looking in the section view E / M2.1, we scaled this same pipe and it measures 6 0. Please review and clarify the drawing scale references. The plan view scale is incorrect on M2.0. It should be 1/8 =1. 7. The geotech report states the bar screen area have existing fill material removed and replaced with structural fill. Should this over excavation/undercut work be included in the bid? If it is, what limits is this to be performed and are there any utilities in this area that may be in conflict with this over excavation. Please include the over excavation and structural fill required per the Geotech Report under Section I, Item 1. Headworks. The quantity of over excavation to include in the bid proposal is 200 CY. Over excavation is not anticipated to present any additional utility conflicts in the headworks area. 8. Is blasting allowed? No. 9. Bid form Can the bid form be revised to include all base bid equipment and list

4 alternate deducts in lieu of writing in all prices? This may be troublesome for last minute changes. No. 10. What constitutes a good faith effort for the MBE requirement? MBE Requirements will not apply to this project. 11. Who is responsible for the gravel driveway access to TMS shown on plan sheet G3.0? The Contractor is responsible for installation of the gravel driveway as part of this project. 12. Is the contractor or the town responsible for the maintenance plan for Holly Oak Lane? The Contractor will be responsible for maintaining Holly Oak Lane during construction. 13. Please clarify where the second screen is to be installed per Only one is shown on drawing M1.0. Please remove all references to the second screen in Section The Contractor is responsible for installing the existing MN Water Screen owned by the Town. A manual bar rack is to be installed as the second screen. 14. Please confirm an office is not required to be provided for the owner s on-site representative. An office is not required for the Owner s representative. 15. Please confirm the owner will provide all water, power, and chemicals for testing at no cost. The Contractor is responsible for any temporary power and water service required for construction, construction trailer and testing. Water service is provided thru the Cityof Columbia. 16. The response to question 14 on Addendum 2 was cut off. Please repost the Answer. Number 14 on Addendum No. 2 Specification Section The measurement and payment calls for unit price work to cover authorized changes in scope of lump sum work in Section I and II.

5 Is this to mean the contractor is to include all rock excavation in the base bid and only authorize changes to scope will make the rock pay item accessible? Section III Unit Price Pay Items: Sidewalk: The Owner will pay the Contractor per linear foot of 5 sidewalk installed at the unit price provided in the contract. Rock removal: The quantity of rock in the bid proposal has been estimated using the Geotechnical Report and the proposed construction plans. The Owner will pay the Contractor per cubic yard for the removal and disposal of rock encountered during construction. 17. Please confirm if all Ductile iron piping is to be restrained with Flex-Ring/Lok-Ring or Gripper Gaskets. All ductile iron pipe is to be restrained. 18. EFFLUENT LINE CHECK VALVE VAULT: Drawing M9.0 is showing the detail of the check valve vault. The effluent pipe is going through the precast vault walls. The pipe needs flanges to connect to the gate valves. Since this is a yard pipe in a vault, we were wondering if a Uni-flange or a Megaflange could be used at this location to facilitate the installation. See specification section , Flange adapters are not shown in the detail. Please review and advise. A Uni-flange or megaflange is acceptable. 19. FLANGE BOLT SETS: We were wondering about flanged pipe joints in valve vaults. Do you want the carbon steel bolts described in the ductile iron specification section? Are galvanized or stainless steel bolts and nuts required in valve vaults? Please review and clarify the flange bolt and nuts in valve vaults. Standard hardware is acceptable for valve vault applications. 20. CHLORINE CONTACT CHAMBER DRAIN LINES: Drawing G7.2 is showing the two 8 drain lines coming out from the Chlorine Contact Chamber structure. We note the two callouts on the east side of the structure for an 8 90 and an 8 PV. Also there is the callout for the 8 tee and an 8 PV. Looking at the enlarged layout of the structure on sheet M4.0, the two drain lines coming out from the structure do not have the indication of PV, plug valves, in the lines. There are mud valves inside the structure to control the draining of the basins. Please review and clarify the two 8 PV outside the structure. The drain lines for the Chlorine Contact Chamber are shown correctly on M4.0. Please provide two (2) mud valves as shown on M4.0 (Valve #401 and #402). No plug valves are required at this structure.

6 21. DRAIN LINES IN THE YARD: Do the PVC SDR 26 drain lines have to be restrained? We are assuming that they will have gasketed SDR 26, PVC fittings. There are MJ fittings where the drain lines transition from ductile iron pipe to SDR 26 PVC pipe. We are listing MJ gland accessory sets with transition gaskets to PVC sewer pipe. Pleases review and clarify. PVC yard drain piping does not need to be restrained. Drain piping under structures will be restrained joint ductile iron pipe and fittings. Transition kids will be required. 22. DIGESTER DRAIN LINE: Drawing G7.2 is showing the digester and the 8 drain line going to manhole number 5. The callout inside the digester indicates, 57 LF of 8 D.I. P, ( SDR 26 ). The SDR 26 reference should be for PVC sewer pipe. The drain line under the digester is ductile iron piped as shown on drawing M6.0. Sheet G7.2 does not show a plug valve in the drain line. Drawing M6.0 does show a plug valve in the drain line. This valve does not appear in the valve schedule. Since the drain line is so short going to manhole # 5, can it continue as ductile iron which would facilitate the installation of the MJ plug valve? Please review and clarify the digester drain line. The drain line is shown correctly on M6.0 and will need to include the plug valve. Please note that the digester decant is also going to connect to this line per clarification in this addendum with a 8 wye. The entire length of drain line should be 8 DIP from the digester to MH # DIGESTER DRAIN LINE: Drawings M6.0 and 6.1, show the 8 drain line coming out from under the digester tank. We do not see an elevation indicated on these sheets. We do notice the invert elevations indicated at manhole no 5. The south west line invert is indicated to be Is this the elevation of the pipe under the digester tank? Please review and clarify the drain line elevation under the digester tank. The 8 drain line will need to extend from the center of the digester with a minimum 0.40 % slope to MH #5. The center line of the 8 90 bend on the drain line at the center of the digester should be This invert at the digester would result in an approximately invert of at MH#5 and still require an inside drop. 24. DROP MANHOLE: Drawing M6.0 is showing manhole no 5. There are two callouts at the manhole for inside drop on the W west and SW south west lines. We looked in the drawing and did not find a detail of a drop manhole. We did find the standard manhole on sheet MD1.0, but it did not show any piping inside the manhole. Drawing G7.2 is also showing manhole no 5 but does not indicate any drop requirements. Please review and clarify the drop manhole piping required. Inside drop piping is required. Please see attached detail.

7 25. SANITARY SEWERAGE CLEANOUT: Specification section , 2.1, C, - Cleanouts lists item numbers 5, 6 & 7. Item 5 appears to be describing a 26 diameter manhole ring and cover. Items 6 appears to be describing a precast concrete manhole components. Item 7 seems to be describing the base of the manhole. Please review and clarify the requirements for the sewer cleanouts. Also provide a detail of a sewer line cleanout. The clean out detail we did find was showing what appears to be MJ pipe and fittings. There is a clean out detail on MD1.1 which should be used for plant drain piping. There are clean out details on PB2.1 which pertain to the admin building. 26. PW PLANT WATER PIPE LINE: Drawing G7.2 is showing the 6 PW Plant Waterline extending around the plant site. We have not found any indication on the plan sheet as to what pipe material to use for this water line. The specifications in section , A & C are describing ductile iron pipe and AWWA C900, class 150 PVC pipe. Please review and advise as to which pipe to use for the buried PW Plant Water line around the plant site. Plant water piping that is above ground was clarified in Addendum No. 2 Buried plant water piping can be either ductile iron pipe of C900 PVC, purple color. Plant water piping under paved traffic areas must be ductile iron pipe. 27. PW PLANT WATER PIPE LINE: Drawing G7.2 is showing the 6 PW Plant Waterline extending around the plant site. We note that the various fittings in the line are designated to be RJ, restrained joint. We need to know if the pipe also should be restrained. Please review and clarify the restraint of the pipe runs. All plant water piping should be restrained. 28. PW PLANT WATER PIPE LINE: Drawing G7.2 is showing the 6 PW Plant Water line extending around the plant site. If the PW water line is to be PVC, does it need to be colored purple? Yes. 29. PW PLANT WATER PIPE LINE: Drawing G7.2 is showing the 6 PW Plant Waterline extending around the plant site. What is the minimum depth of bury for the PW water line? Minimum depth of bury is PW PLANT WATER HOSE BIBBS: The Utility Piping Plan is showing hose bibb stations around the plant site, with a reference of HB. There is no detail referenced or indicated. We found some details on sheet MD1.1 for Wash Hose

8 Station and Hose Bibbs. The printing of the wording in the details is distorted and hard to read. Please reissue this sheet with the wording clearly shown. We also need to know what piping material to use for the vertical risers up to the hose bibbs. Is the pipe PVC or is it to be copper pipe? Please review and clarify. Please see MD1.1 attached. 31. EFFLUENT FORCE MAIN : Drawing G6.1 is showing the 12 PVC Effluent Force Main extending away from the Effluent Pump Station to the connection point with the existing pipe. The callout for pipe is 12 PVC C900 Force Main, RJ. Looking in the specifications for the class of pipe, we looked in section Sanitary Sewer, which states in paragraph 1.1, Summary, A, 2, Force Main. We looked down in paragraph 2.1, Materials, A - Pipe and fittings, we did not find a listing for C900 PVC pipe. The only listing for C900 PVC pipe is in section Water Distribution. Please review and clarify the C900 PVC pipe to be provided for the Effluent Force Main line. Effluent force main shall be 12 RJ C900 DR 18 (Class 150). Green color is required. 32. Specification Section Laboratory Fume Hoods. 2.2 Manufactures. We would like to request5 that Mott Manufacturing be included as an acceptable manufacturer for Chemical Fume hoods. Mott is not approved as an acceptable manufacturer for chemical fume hoods. 33. Specification Section Laboratory Casework 2.3.A Manufacturers we would like to request approval of Mott Manufacturing for this section as well. Usually the hoods and lab casework is provided by the same company for coordination purposes. Mott is not approved as an acceptable manufacturer of lab casework Specification Section Laboratory Fume Hoods 2.6.A Work surfaces. Typically a fume hood, worktop is 1.25 thick at the outer edge and dished or recessed to 1 thick. Please advise if 1 thick or 1.25 thick is required. Per Spec A, the work surface is 1 thick with ½ raised edges at sides and rear. 35. Specification Section Laboratory Fume Hoods 2.7.A fume hood base cabinets. Base cabinets beneath fume hoods take a lot of abuse. Would the Architect entertain changing material type to Galvanized Steel as an extra layer of protection against corrosion in this area. The cabinets would also be painted to match hood per SEFA standards. Provide base cabinet as specified in Section

9 36. In an effort to provide the Town of Chapin an accurate and cost beneficial bid we request Section I Lump Sum Pay Item in the Bid Proposal be changed to one Lump Sum number encompassing all items currently included in Section I. After the bid the lowest 2-3 contractors could be required to provide a breakout similar to the current Section I. The current bid form is at the request of the Town of Chapin and shall be used. 37. Provide list of equipment that needs to be included in Section II No. 7 of the bid Proposal. The balance of all other major equipment required for a complete and operable plant (not included in Section II No. 1 through 6). 38. Advise if under slab piping needs to be encased in concrete. All piping under structures must be encased in concrete. Piping under slabs such as driveways, housekeeping pads or building floors does not need to be encased in concrete. 39. Provide the required Bid Bond form for the proposal as required in the Invitation to Bid. Please use a Surety Company s Standard Bid Bond form. 40. Spec Section Paragraph 2.03C states The handrailing shall be in conformance with the handrail specifications found within this set of bid documents. We cannot locate any handrail specification in the TOC or within the specifications. Please provide a handrail specification or revise the secondary clarifier specification to include handrail spec language. Please see Addendum No. 2 which includes Specification Section Aluminum Pipe and Tube Railings. 41. EFFLUENT PUMP STATION FORCE MAIN: Drawing G6.1 is showing the 12 PVC C900 force main extending out to the existing PVC Effluent Line at Holy Oak Lane. Looking on sheet G7.1 - Process Piping Plan, we see the Effluent Pump Station Force Main also shown. Sheet G7.1 has a note that indicates to install a 12 RJ plug and abandon in place old plant effluent line. Sheet G6.1 does not have this note. It indicates to cut and tie to existing effluent line. Is the plug to be installed? Please clarify. Please install the RJ plug per sheet G7.1. The effluent line from the old plant any be utilized at a later date by the Town. 42. VALVE SCHEDULE: Valve tag number V001 is listed twice, for the 2 gate valves with the 2 square nut operators. These are the first two valves at the top of the schedule.

10 Correct the second valve tag number to #V002 for 2 water to eye wash at chemical tanks. 43. DRAIN PIPING YARD : Addendum No 2, item no 56, response states that all drain piping that is not under a slab can be C900, SDR 26. Our understanding of pressure rated PVC pipe with a class of SDR 26, is PR160, D2241, bell joint pipe, which has a steel pipe outside diameter. PVC pipe that is made per AWWA C900 standards has a ductile iron pipe outside diameter. We are assuming that you want to have the steel pipe size drain pipe. We want to know what type of fitting do you want to have with the SDR 26 PVC pipe? There are a few fittings shown on the yard piping plan. Please clarify that you want the SDR 26 steel pipe size drain pipe and what fittings to use with the pipe. Drain piping that is not under the slab can be ASTM F 794 per Section , 2.1A Please provide a detail for the concrete paving at the Headworks. Please see Revised Sheet G5.6 dated Addendum No. 3 Revisions In our last list of questions, item 4, asked about the PVC drain pipe materials. In addendum No 2, you had indicated that the drain pipe not under a slab can be C900, SDR 26. Our initial understanding of the drain line notation or callout on Sheet G7.2, 8 PVC SDR 26 let us to believe that the yard drain pipe would be PVC sewer pipe, with a class rating of SDR 26. The yard drain lines also include the 4 sanitary drain line coming from the Administration Building. This is a heavy wall sewer pipe and fitting system. Specification section Sanitary Sewerage, does not list the C900, SDR 26, pipe material. This is making us wonder if it should be considered for use in a gravity flow line. Please clarify if the SDR 26 sewer pipe and fittings are acceptable for the yard drain lines. 46. On Sheet M8.0, the section view of the Plant Drain Lift Station calls for the wetwell interior to be coated per Should this be per Spec Section ? This is correct. Please coat per Section End of Addendum #3