INVITATION TO TENDER ITT / NO. PS BURRARD BRIDGE REHABILITATION QUESTIONS AND ANSWERS NO. 4

Transcription

1 ISSUED ON JANUARY 19, 2016 Q1 Can the City provide the Tenderers with a best known timeframe for when the Provisional items of work might take place and when that decision would be made? A1 Q2 A2 Q3 A3 Q4 A4 Q5 The provisional items will depend on the tender results and whether they can fit into the budget. It is anticipated a decision on their inclusion/exclusion will be in February The Pier 6 added diaphragm looks to be fairly difficult (but achievable) to form; and pouring will be difficult, but is it intended that the top surface of that diaphragm be to a rough finish - meaning not struck off or floated, and is the space or gap intended to truly be 100 mm or is there an allowable variation on that dimension? It appears that the only method to finish the diaphragm would be through the joint opening, but it doesn't seem wide enough for that, either. Please help us understand the designer's intention and constructability. The finish on the top surface is not critical provided top cover is achieved. We anticipate the gap to be formed with a compressible stay in place form material, rigid Styrofoam or similar. Do the Crossbeam encasements, shown on drawings 316, 317, 319, 320 and others - require the triangular 200 x 100 fillet to be removed completely to facilitate the 3 each 25M bars located in that area, or can it be "approximate" meaning partially removed? Here are a couple screenshots for that fillet detail. The fillets need to be sufficiently removed to allow placement of the 3 25M bars. The General Notes for "Removal and Disposal" on drawing 302 indicate that a maximum 7 kg chipping hammer shall be used, unless approved by the Contract Administrator. Please provide guidance on where the 7 kg hammer must be used and where other sized hammers or demo methods are likely to be approved for use (handrail, sidewalk, anchorages, bearing replacement, etc.? Consideration will be given to using large chipping hammers in areas where does not appear likely to cause damage or removals beyond those desired. For example, bulk removal of the concrete fence away from the sidewalk interface. Prior to considering a larger chipping hammer or alternative methods the Contractor will need to develop a work methodology demonstrating, do the Contract Administrator s satisfaction, that the removals can be achieved in a controlled fashion. Supplemental Specification 03300S for Cast In Place Concrete indicates in section Concrete Removal for Repairs - that spalled or delaminated concrete shall be removed to sound concrete. See the attached picture as an example of one fascia girder's delamination which would require overhead shotcrete application (reference Supplemental Specification 03371S). Does the City anticipate that the extensive removal of damaged concrete, on load bearing items, might necessitate support or shoring to ensure the remaining concrete element's capacity until repaired? If this occurs, will this shoring be covered as an "Extra"? 1

2 A5 Q6 A6 Q7 A7 Q8 A8 It is not anticipated that the concrete removals for the concrete repairs will necessitate temporary shoring of the structure. If a scenario is found where the extent of deterioration and removals necessitate temporary shoring, the Contract Administrator and the Contractor would review the location and develop an appropriate plan. Shoring would be considered an extra in this situation. To ensure the quality of the finished concrete, and prior to pouring - CIP and/or Shotcrete locations will be monitored for vibrations caused by the live loading on the bridge. If the measured vibration exceeds any available industry standard allowable levels, will the City allow for the bridge to be closed during (and after) a pour? If not, will the City take responsibility for concrete defects due to vibration caused by live loads? The bridge will not be closed during concrete placements. Similar concrete repairs have been completed in two previous construction package with not concerns identified due to vibration. Drawing E110 Please provide specification for Type 5 JB as it is not listed in the MMCD or the MOTI documents. Type 5 Junction Box shall be Synertech Type 5 junction box (17 x 30 x 24 in). Junction box lid shall be Tier 22 and shall be secured with Hex bolts. Junction box lid shall be supplied with CoV label. Drawing E101A Fixture schedule. Does the Pigeon Patrol spikes go the length of the arm or only on the fixture head? The spikes are intended to be installed on the fixture only. 2

3 Q9 A9 Q10 A10 Q11 A11 Q12 A12 Q13 A13 Q14 A14 Q15 A15 Drawing E115A, Elevation F (Double Davit Bridge Truss Luminaire). New teck cable gets installed from the light fixture to where? Refer to drawing E108. Teck cable is installed between luminaires and junction box below deck near vertical truss members. On drawing it shows existing catwalks. Where do access these catwalks from? Is there access from P3 & P4? Access is through a hatch in the sidewalk at Pier 3, through the pier, onto the pier 3 bearing seat area at the end of the truss. Drawing regarding concrete repairs can you provide locations and depths for each concrete repair? Providing access especially from Pier 1 to Pier 4 over the water can prove to be very expensive if we do not know the location and extent? Repair locations are to be identified as part of the work. See Questions and Answers 3 and amendment 3 for clarification on access requirements in zone 2. Drawing to 357 There seems to be some inconsistencies on the location of stainless rebar and black rebar. Can you please check and clarify? Reinforcing shall be stainless for top and side surfaces and black bars for bottom surface. Schedule 10 SGC 2 Traffic Control Item 5 states the contractor must use rebound delineators for traffic control on the bridge. Is it intended to have the rebound delineators installed to separate each lane of traffic during construction regardless of the driving direction or just between northbound and southbound lanes? Also, provide information on the spacing for the rebound delineators? The rebound delineators will be required between the adjacent north and southbound travel lanes. They are not required between the two northbound lanes. Spacing should be as per Traffic Control Manual for Work on Roadways (Second Field Edition) published by the B.C. Ministry of Transportation and Highways. Rebound delineators will also be required for tapers on the bridge (if tapers are part of the Contractor s traffic management plan). Drawing No Note 5 states that the intermediate embedded plate EP1 is required for fence panel length greater than Four typical panel details (fence panel length >3000) shown on Drawing Nos. 364 & 365 show three EP1 per panel. Panel types 1 to 4AE has panel lengths of less than Will these panels have only two EP1 per panel? Please confirm? Correct. Panel type 1 to 4AE only have two EP1. Drawing No Fence Post Schedule shows Pedestrian Scale Lights (PSL) (2 each) for Post Types A6-1E and A6-2 whereas Detail of Post A6-1E on Drawing No. 367 and Detail of Post A6-2 on Drawing No. 368 do not show anchorage for PSL on these posts. Please clarify? There is no PSL on top of these two new posts. PSL will be located on top of existing stair walls outside these two posts. Refer to drawing E107 or for location of PSL at Pier 1 3

4 Q16 A16 Q17 A17 Q18 A18 Q19 A19 Q20 A20 Q21 A21 Q22 A22 Q23 There seems to be inconsistencies on the sizing of the dowels shown in various sections of the fence posts. For example, Drawing No Fence Post F Detail Section B mentions 20MS Dowels whereas Section A mentions 15MS Dowels. Please clarify? Dowels for main post on truss span shall be 4-20M each side and 3-20M each side for intermediate post. Where are the limits (extents) of sidewalk overlay shown at south end for east and west sidewalks? Please advise? The south extent of the sidewalk overlay is the south abutment joint. Is the quantity of Sidewalk Replacement (Re-grade and Replace) mentioned under Pay Items 3.20 is for only one location shown in Drawing 349 (NE Abutment)? Please clarify. Also, please advise on the thickness of concrete sidewalk to be replaced under Pay Items 3.19 & 3.20 and if there are any reinforcing requirement? Regrade and replace sidewalk under pay item shall include regrading and replacing north east sidewalk shown on drawing ; pay item shall include regrading and replacing north west and south west sidewalks shown on drawing and respectively. Sidewalk details are to be per MMCD standards. With reference to Pay Item 3.18 Partial Depth Patch Repairs of Sidewalk, please advise on the anticipated depth for patch repairs and locations? Depth of partial depth repairs shall be to 25 mm below top reinforcing or to sound concrete, whichever is deeper. Please advise on the total number of existing concrete fence mounted light poles to be removed on both east and west sides? 64 luminaire poles (32 on east side, 32 on west side), 4 flood light poles east and west sides, immediately north and south of Pier 3 and Pier 4. There appears to be chain link fencing alongside the existing concrete fence and on the outside edge approximately from Pier 3 to Pier 1 c/w Chain Link Fence man gates at Pier 1 and approximately from Bent 19 to Bent 17 on both east and west sides of the bridge. Please provide details of the existing chain link fence installation including mounting details and advise under which pay item the removal of this fencing to be included? Record drawings are not available for the chain link fences mounted to the bridge rail. Details can be field reviewed. Payment for removal of the chain link fences will be include in item 3.00 Removal and Disposal of the Existing Fences. Drawing No sidewalk overlay details show existing Asphalt Mastic to be removed. Is this asphalt mastic also to be handled as asbestos containing material? And does this asphalt mastic run the entire length of the bridge on both east and west side? Please clarify? Yes, the existing asphalt mastic is expected to contain asbestos and runs on both sides of the sidewalk curbs for entire length of the bridge (between abutment joints). Good morning Brian, have made an inquiry about the drawings for CMB-810 s required for this project. There are no measurements on how deep the recessed strips need to be or where they 4

5 are position on the barrier as in the height? you please inquire on our behalf. A23 The recess details are shown on drawing Recess shall be 130 mm wide x 10 mm deep. Q24 Please refer to drawing 387; Please confirm that there are a total of 5 complete catwalks being installed below the deck of the main truss. A24 Q25 A25 Q26 A26 Q27 A27 Q28 A28 No, the plan drawing indicates a symmetric plan at the truss centerline. The catwalks are to be installed across the full length of the truss. There are 9 floorbeam locations with catwalks. Please advise if the concrete surfaces are required to be painted after concrete repairs. If so, please provide specifications. The patch locations below the deck are not to be re-painted. With reference to drawing , Section DD there is a notation as follows: Pin thread to prevent nut rotation Typ. Please clarify whether this requires that each nut be fixed with a cotter pin after tightening? If so, please clarify whether Castle nuts are to be used, or if standard or heavy hex nuts are to be drilled and whether the nuts should be drilled before or after galvanizing. Please also clarify whether all nuts in the new fender system are to be pinned, or just the fender panel sheathing nuts? The notation should be to peen threads, ie damage the threads to prevent nut rotation. Drilling and installing cotter pins for all the nuts will be very time consuming and expensive. Would lock washers or loctite be considered as an alternative? See Answer 26 above. Supplement Specifications Section 03300S, Subsection 1.2 refers to CSA A23.1-M as a reference for Concrete Materials and Methods of Concrete Construction. Subsection Curing states that for Temperature, Concrete shall not be placed when the ambient temperature exceeds 25C. And, Concrete more than 45 minutes old shall be rejected. a. Regarding temperature - Does the City mean that the "Concrete Temperature shall not exceed 25C," or do you truly mean the ambient temperature? An Ambient Temperature of 25C is possibly fairly low if you intend for pours to occur during portions of the summer. The referenced CSA Specifications, Section and its referenced Table 14 would allow for a Concrete Temperature of 30C to 32C for most of the items on this project. Please clarify or confirm both Ambient and Concrete temperatures allowed. b. Regarding Time for placement - Does the City truly desire the maximum 45 minute placement time? The referenced CSA Specification, Section would indicate a maximum of 120 minutes. Please clarify and/or confirm. a. The upper temperature limit of +25 degrees applies to the placement of the sidewalk and stair overlay, and the new sidewalk deck surface at the widening. b. The specification for a 45 minute placement time is intentional. Consideration may be given to an extended placement time on a case by case basis. 5

6 Q29 A29 Q30 A30 Please reference the Tender's Schedule of Quantities and Prices. It appears to be missing an item for "Payment Clause 10.76, East Barrier Base Curb." Please confirm. There also appear to be discrepancies in the quantities for a few of the Provisional items, as well. a. Please confirm whether these quantities are right: i = approx 75 M; ii = approx 27 EA; iii = approx 27 EA. There should be a payment item for East Barrier Curb, this will be added by amendment. i = approx. 57 ii = approx. 27 Actual payment will be based on the final post layout confirmed during shop drawing preparation. Please provide a location for (12) Type T light fixtures. Type T flood lights are installed on luminaire pole H3B-4-1,H3B-1-1, H3B-11-2, and H3B-6-1. Refer to sheets E108 and E109 and elevation F on sheet 115B Q31 Please refer to Dwg 355. There is a requirement to perform full depth concrete removal in each sidewalk area adjacent to the streetlight poles being replaced. Under what pay item is this work to be included? A31 Payment for the street light supports is under item 5.08 Street Light Supports. Q32 A32 Refer to Answer 7 above. Q33 A33 In some areas the existing electrical feed to existing roadway luminaires may be through the cast-inplace duct in the concrete fence. In other areas, luminaires are fed with cable routed along the backside of the concrete fence. Q34 A34 Yes, if a 2m wide sidewalk can be maintained this would be acceptable. Q35 A35 Recent testing has revealed 1-5 % Chrysotile Asbestos by mass. If further information is required by the landfills to price, a report can be shared. 6

7 Q36 A36 Drain pipe shall be to ASTM A53, galvanized after fabrication. Q37 A37 We anticipate the bearings were painted with lead based paint at original construction. Little to no paint remains, however there may be traces of lead remaining. Q38 A38 The paint system on the existing catwalk rails has not been tested for lead and the date of application is unknown. For bidding purposes assume the paint contains lead. Q39 A39 Refer to Questions and Answers No. 3, Answer 46. Q40 A40 Spacing should be as per Traffic Control Manual for Work on Roadways (Second Field Edition) published by the B.C. Ministry of Transportation and Highways. The Contractor is expected to propose a grout product so the exact specification is not known at this time. However, it is anticipated to be a non-shrink product suitable to the conditions. Q41 A41 Assuming the question is related to drawing , vertical bars shall be 15MS. Q42 A42 Assuming the question is related to drawing , ties in the fence panels are to be 10MS. Q43 A43 All three faces should be roughened as per construction joint specifications. Q44 A44 No, Panels shall be constructed to suit the grade on the bridge, not square. 7

8 Q45 8

9 A45 Reduced cover to 30 mm on the baluster sections is acceptable. Q46 A46 Imperial bar size equivalents will be accepted. Q47 A47 Exposure class should read C-1. Q48 A48 The values in the precast fence panel schedule will take precedent. Q49 A49 Panel dimensions will be reviewed and confirmed in issue for construction drawings. Q50 A50 Panels are to be cast to match the road grade. Q51 A51 See Answer 41 above. Q52 A52 Yes, where fence panel types are specified on just one side of the bridge, the fence panels are symmetric. Q53 A53 Q54 This can be assumed for bidding purposes; however slopes are to be field confirmed prior to fabrication. Regarding the sidewalk overlay, the specifications require removal of concrete to 10mm above the top mat of rebar. The as builts show the top mat being embedded 25mm from surface which results in a 15mm demo. The drawings however say 70mm of concrete to be removed. Please confirm the depth of 9

10 concrete to be removed. INVITATION TO TENDER ITT / NO. PS A54 Please see QA #3. 10