Questions and Answers to Project Documents — Business Opportunities
PROJECT:  Concourse B Xcel Transformer Vaults Re-Life
NUMBER:  201845859-00

Current as of:  10/23/2019
 
Question Number  1:   Regarding the vault lids that allow for access into the Xcel Transformer locations from the Apron Level: could you please provide an anticipated weight (lbs) for the existing lids? Could (we) anticipate removing these lids during construction, adhering to the following criteria: 1) areas to be delineated with temporary concrete barrier with bolted fence on top of the barrier…preventing both vehicles and pedestrians from entering; and 2) area delineated to never impact adjacent VSR’s?
    Answer:   The approximate weight for the vault lids is approximately 15,000 lbs. Concrete lids can be removed for the duration of construction operations (at each vault). Temporary protections will need to be submitted to ensure the following: 1) maintain security control of the site; 2) ensure airport is able to maintain safe operations around our work area; 3) maintain weather protection of the vaults--do not allow water infiltration; and 4) impacts to adjacent VSRs need to be addressed through normal channels via shutdown requests.
Question Number  2:   If the (vault) lids can’t be removed during all of phasing, what would be an allowable time frame to have these accesses open (hours / day)?
    Answer:   Any temporary operations can be treated as a shutdown request, which will need to be submitted in advance for approval.
Question Number  3:   There are five (5) Overhead Coiling Fire Doors on this project. However, (there are) no specifications for these doors. Can I please ask for some direction for these doors? Are they insulated or non-insulated? Are they manual or motor-operated? Fusable links vs. connection to smoke/fire alarm system? Standard finish vs. powder-coating? Smoke seals?
    Answer:   Overhead Coiling Fire Doors are existing. Some are to be removed and others are to be removed and re-installed.
Question Number  4:   We are interested in participating in the construction and site work for the Chung Tai Zen Center project . While qualifying for several jobs regarding ceiling and gypsum work, our professionals at Strada Drywall specialize in fire tape, fire wall, finishing, hanging, and texture to perfection. Our supplier company for materials are provided through Old Western Paint Co Inc., a retailer offering paints, varnishes, supplies & other products. As a local business in Grand Junction, our company strives to provide nothing but the best services around the state of Colorado. In addition, we would also like more information regarding this opportunity. Please contact our office via this email address or phone number below if any questions or concerns arise. Thank you for your time.
    Answer:   I believe that this was sent in error, as you refer to the Chung Tai Zen Center project, but you referenced the Concourse B Transformer Vaults at Denver International Airport. We do not have a Chung Tai Zen Center project. If you want to see the project documents for the Concourse B Transformer Vaults project, they can be found at: http://business.flydenver.com/bizops/bids.asp
Question Number  5:   During the Pre-Bid walk it was indicated that Xcel required 10' clearance to service the existing Transformers . Please confirm the 10' clearance is from the front and provide the side clearance which must be maintained.
    Answer:   If necessary to work near live transformers. DEN and Xcel Energy will require the use of appropriate PPE and the use of a temporary physical barrier around the transformer. It may encrouch on the required operational clearances, but will require that a plan be submitted and approved by DEN.
Question Number  6:   During the Pre-Bid walk it was indicated the vaults had to be constructed in two phases. Please identify the transformers which can be taken out of service during each phase.
    Answer:   It was indicated that a minimum of two phases would be required. The contractor is to determine final phasing to complete the work. The redundancy in the electrical service is separated by a 3 hour fire wall.
Question Number  7:   During the Pre-Bid walk it was indicated the vaults had to be constructed in two phases. Please provide details which indicate acceptable locations of construction joints in grade beams.
    Answer:   The Contractor is to submit construction joint layout for DEN review. Construction Joints in beams should occur at 1/3 span of a beam.
Question Number  8:   The documents indicate the scope of work which is performed by Xcel Energy. Please provide the anticipated durations for this scope of work.
    Answer:   Xcel Energy's scope of work is to be completed concurrently with the work being performed by the contractor. Schedule will need to be provide to Xcel Energy to coordinate performance of work.
Question Number  9:   The documents indicate that the finish on the existing walls be removed to "provide a smooth, clean surface for painting." Please confirm that the existing surfaces to be removed are not "Toxic or contain Hazardous Materials".
    Answer:   The environmental survey report is to be provided in Addendum 1.
Question Number  10:   Reference Specification Section 101423. Para 1.3.A indicates an allowance for signs is stipulated in Specification Section 012100. Please provide this specification section.
    Answer:   Addendum 1 will revise specification section 101423 to remove reference to allowance. New room indentification signage is to be included in the bid tab.
Question Number  11:   The following Specification Sections appear to be missing from the project Documents. Please provide or confirm they are not required: 012910 SCHEDULE OF VALUES, 013223 CONSTRUCTION LAYOUT, AS-BUILT AND QUANTITY SURVEYS, 013233 PHOTOGRAPHIC DOCUMENTATION, 013516 ALTERATION PROJECT PROCEDURES, 014210 REFERENCED MATERIAL, 014225 REFERENCE STANDARDS, 014545 SPECIAL INSPECTION AGENCY AND OWNER TESTING AGENCY(S), 015050 MOBILIZATION, 015215 FIELD OFFICES, 015525 TRAFFIC CONTROL, 015810 TEMPORARY SIGNS, 016610 STORAGE AND PROTECTION, 017835 WARRANTIES AND BONDS, 017900 DEMONSTRATION AND TRAINING, 019113 GENERAL COMMISSIONING REQUIREMENTS, 077100 ROOF SPECIALTIES, and 099600 HIGH PERFORMANCE COATINGS.
    Answer:   Addendum 1 will add the following specification sections: 012910 SCHEDULE OF VALUES, 013223 CONSTRUCTION LAYOUT, AS-BUILT AND QUANTITY SURVEYS, 013233 PHOTOGRAPHIC DOCUMENTATION, 013516 ALTERATION PROJECT PROCEDURES, 014210 REFERENCED MATERIAL, 014225 REFERENCE STANDARDS, 014545 SPECIAL INSPECTION AGENCY AND OWNER TESTING AGENCY(S), 015050 MOBILIZATION, 015215 FIELD OFFICES, 015525 TRAFFIC CONTROL, 015810 TEMPORARY SIGNS, 016610 STORAGE AND PROTECTION, 017835 WARRANTIES AND BONDS, 017900 DEMONSTRATION AND TRAINING
Question Number  12:   Reference SC-7 Prosecution and Completion of the Work. This section indicates the work shall be completed within 550 consecutive calendar days from the notice to proceed. Would DEN consider adding 30 days to the start of the project which would allow for a submittal period prior to the start of the work, or increasing the overall duration to 580 Calendar days?
    Answer:   Addendum 1 is to revise the project duration originally stated in SC-7 Prosecution and Completion of the Work.
Question Number  13:   Reference SC-7 Prosecution and Completion of the Work. This section indicates Milestone dates from the NTP. Taking into consideration the vaults have to be contructed in Phases, it is highly unlikely that many of these Milestones will be achieved. Would DEN consider modifying the bid form to allow the contractor to propose Milestone dates from NTP?
    Answer:   Addendum 1 is to revise the project duration originally stated in SC-7 Prosecution and Completion of the Work.
Question Number  14:   If the vaults are to be reconstructed in (2) separate phases, then (1) phase of the vault reconstruction will be "cut-off" from access to the Apron-level hatch. If concrete is to be pumped in through the hatch, please advise what type of barrier (height, fire rating, distance from live transformer, etc.) is required to separate the line pump hose from the active transformers.
    Answer:   If using the Apron-level hatch to access the vault while the Xcel equipment is live, a temporary separation inside the vault is required. Temporary protection will need to be submitted by the Contractor and approved by DEN.
Question Number  15:   At Vaults 8W, 6W, and 3W what type of construction barrier is required to separate the tunnel areas from the vaults? As long as clear separation between the public and the work zone is maintained, is that adequate? Note: numerous overhead obstructions exist if full-height barriers are required at these vault perimeters.
    Answer:   The Contractor must maintain existing fire rating in areas with energized transformers or switch cabinets. For areas not enclosing energized transformers, a safety separation to define construction limits is required and must be controlled by the Contractor at all times. A temporary barrier plan is to be submitted to and reviewed by DEN.
Question Number  16:   It was verbally stated during the pre-bid conference that a full-time safety person is required, and for each shift if double-shifts are utilized. It was then asked to formalize this bid question during the subsequent walk-thru, when somebody asked if the superintendent could suffice as this person. Please advise requirements for on-site safety personnel staffing on this project.
    Answer:   The requirement is to have a qualified (please see ROCIP Safety Manual for qualification criteria) safety professional assigned to the project full-time, for all shifts. Their only duties are to administer the safety program for this project. 0
Question Number  17:   Are interface agreements drafted/available on this project for work that is to be coordinated with XCEL energy?
    Answer:   Interface agreements are not available for work with Xcel Energy.
Question Number  18:   Does the 110 day duration for the first vault (1C) begin after Xcel de-energizes and removes the transformers? Are Xcel's working days to be included in the contractor completion schedules? If so, what is anticipated duration for Xcel to remove and reinstall a vault "phase" of transformers?
    Answer:   Coordination of work to be performed by Xcel Energy should be included in the construction schedule. Addendum 1 is to revise the project duration originally stated in SC-7 Prosecution and Completion of the Work.
Question Number  19:   Drawings do not depict existing slab thickness. It was stated during the pre-bid walk that the existing slab on grade is 6" slab on grade. Please confirm thickness and advise what existing reinforcement within the slab is, for both the slab within the Vault and the Baggage Tunnel floor slab outside the vault.
    Answer:   The geotechnical report is to be provided in Addendum 1.
Question Number  20:   Are existing CMU walls which are to demolish grouted solid, or only grouted solid at bond beams? If only at bond beams, please advise bond beam locations.
    Answer:   Because the existing masonry walls were originally designed to function as a 3-hour, fire-rated assembly, it is assumed that the walls have been grouted solid with a minimum of an every-other cell pattern; however, no destructive testing has been performed and record drawings do not include that level of detail. It is the Contractor’s responsibility to account for reinforcement of existing masonry walls.
Question Number  21:   We observed during the pre-bid job walk through that the existing CMU walls which are to demolish are filled with loose fill insulation, that appears to be similar to small "pellets". These pellets will potentially need to be vacuumed out of the wall prior to demolition, so that a mess is not created. Can you please confirm if this type of insulation occurs at all CMU walls, and if it is in contractor's scope of work to remove it?
    Answer:   Please refer to the general notes on the demolition sheets.
Question Number  22:   Vault 8W- Demolition Plan A101 depict the removal of the baggage tunnel floor slab into an existing room at the SW corner of the work scope area. What is the wall construction of this existing room? What are the finishes in this existing room, and what extent of finishes restoration is required within the room (i.e. flooring, paint, etc.)? Can the sawcut line within this room (running north-south) be shifted approx. 1'-to the east to avoid replacement of that section of wall? Is there concern of any embedded in-slab utilities, both inside the vault and outside at the baggage area slab removal locations?
    Answer:   The extents of the existing floor slab to be removed at the southwest corner of the drawing, in particular, the portion of slab indicated to be removed is shown to extend through an existing wall that is not within the scope for this project. The extents of the slab removal will be revised to exclude removal from under this out-of-scope existing wall, which is located west of gridline W50.1, running north-to-south, between gridlines N4 and N2.2. This existing wall is not to be modified nor undermined. It will be the responsibility of the Contractor to confirm all existing conditions prior to commencement of work. Revised sheet included in Addendum 1.
Question Number  23:   At Vaults 3W, 6W, and 8W, there are existing bollards and guardrail at the baggage tunnel slab (i.e. area outside of vault) that is to be replaced. It is GC responsibility to remove, salvage, and reinstall these items?
    Answer:   The Contractor is responsible to remove, salvage, and reinstall existing items that are affected by construction operations.
Question Number  24:   Can a SDR be submitted to close a lane of the VSR (vehicle service route) to access hatchways for concrete pumping? If so, can the lane be closed during the day, or will it need to occur off-hours? If off-hours, please provide the window of time the lane can be closed. Will traffic control and flagging be required during the lane closure?
    Answer:   The Contractor will need to coordinate in advance with DEN Tactical Planning and Operations to ensure construction activities do not adversely impact DEN and Airline Operations.
Question Number  25:   Rat slab thickness and mix design is not provided. Please provide. Additionally, we have concern that rat slab will fail since it is placed on expansive soils. In the event of failure during warranty duration due to soils heaving, is Contractor responsible to repair? If so, define what constitutes a rat slab failure (i.e. surface cracking, spalling, or crumbling)?
    Answer:   This is a non-structural slab. A 2” concrete thickness is acceptable. A minimum 2000 psi 28-day compressive strength is required. Concrete mix design will need to be submitted to DEN.
Question Number  26:   Cut sections on structural drawings do not depict reinforcement requirements at the Transformer housekeeping pads. Please advise.
    Answer:   The housekeeping pad reinforcement is specified in the plan notes as #4 rebar at 12” o.c., top and bottom.
Question Number  27:   Detail 3/S504, Note #1: What vaults have PT Slabs above? What is embedment depth of the Hilti 1/2" drop-in anchors?
    Answer:   Per the existing drawings, all the rooms except rooms 1C and 3C have PT floors above (Contractor to verify in field). The ½”Ø Hilti HDI-P anchors have a length of 1in.
Question Number  28:   KN1/New Construction Plans (Architectural)- Is a detail for the Masonry Isolation Joint available?
    Answer:   Masonry Isolation Joint has been provided in Addendum 1.
Question Number  29:   At Vaults 3W & 6W, Architectural New Construction Plans show the new CMU wall along GL W19, W35 (respectively) extending beyond the vault and tying into an existing wall. Structural drawings do not depict this, please advise.
    Answer:   Architectural drawings show the walls along W19 and W35, in vaults 3W and 6W, respectively, extend from the foundation wall at N6 to an existing reinforced concrete wall, approximately 4’-0” north of grid line N5.2, and another, similar wall along the same grid line, from the existing reinforced concrete wall approximately 3’-0” south of grid line N5.2, to its termination with the existing masonry wall just north of grid line N2.3. Refer to Key Note 1 on sheets A111 and A112.
Question Number  30:   It was mentioned at the pre-bid job walk that a partial-height CMU wall is needed at the 8W Vault Transformer near GL W49.5. This CMU wall is not shown on the drawings. Please provide an updated plan sheet if it is intended to add this wall.
    Answer:   Updated plan sheet has been added in Addendum 1.
Question Number  31:   Removal of damp-proofing? Discussed at pre-bid job walk but not shown on drawings? Spec requirement for removal of damp-proofing, i.e. is sandblasting required or just scraping?
    Answer:   Contractor to propose method of removal so as to provide a clean, smooth surface appropriate for the application of the required wall paint.
Question Number  32:   There is no specification for Fire Detection and Alarm; however, it was determined at the sitewalk that existing fire alarm signage will need to be removed/re-installed at Vaults which have perimeter wall work which affects existing fire alarm devices. Please confirm this work scope is by Contractor.
    Answer:   Existing fire detection and alarm equipment and related infrastructure within the vaults will be removed as part of demolition. None of this equipment will be reinstalled nor replaced. For existing fire alarm and detection systems outside of the vaults, devices are to be protected in place and must be maintained, without interruption, over the course of the project. An interim fire permit will be require.
Question Number  33:   Soils report has not been provided. Is a soils report available? If not, please advise what the over-excavation requirements (if any) are beneath the new rat-slab.
    Answer:   See response to question #20.
Question Number  34:   Note 7 on Sheets E101 to E105 states the EC is to provide new thermostat conduit with MC providing cable. Detail 2 & 5, Note 5 on Sheet E501 states the EC is coordinate with MC to provide all new control raceway and conductors. Confirm that controls Contractor is responsible to provide all conduit, raceway, and cables necessary for controls scope of work.
    Answer:   Scope assignment is the responsibility of the General Contractor.
Question Number  35:   Sequence of operation references for makeup air units and crawlspace exhaust air systems refer to the existing NAE and network control panel. Confirm the NAE and network control panel refer to the Johnson Controls Metasys Network Application Engine (NAE) control panel. (M602)
    Answer:   The intent is for new equpiment is to utilize the existing NAE controls system, in place. An I-LON ID schedule has been provided on sheet M602 to further clarify which panels are intended to be utilized.
Question Number  36:   The fan schedule notes state the humidistat and thermostat are to be furnished by the equipment supplier. Confirm that theses controls are to be provided by the temperature control Contractor for input into the direct digital control system as shown per the controls diagram on drawing M-602, and not the equipment supplier.
    Answer:   The intent of the schedule notes is to clarify these instruments and, in general, need to be provided and coordinated with the manufacturer, mechanical contractor, and/or controls contractor. Scope assignment is the responsibility of the General Contractor.
Question Number  37:   Which trade is responsible for providing the local control panels shown on Sheet P601 serving the sump pumps?
    Answer:   Scope assignment is the responsibility of the General Contractor.
Question Number  38:   Is the intent to truly over excavate or just excavation to create the crawl space?
    Answer:   See response to question #20.
Question Number  39:   Please confirm thickness of rat slab in crawl space.
    Answer:   See response to #25.
Question Number  40:   Can you send the bid form as an Excel spreadsheet?
    Answer:   The bid form cannot be sent as an Excel spreadsheet.
Question Number  41:   Due to the constraints and equipment required in constructing this project can scrubbers be utilized in lieu of electric or propane equipment?
    Answer:   DEN and DFD will only allow the use of electric or CNG equipment in the basement. If that equipment does not exist for a specific task, a proposed alternative will need to be approved by DEN. Any proposed method will need to include scrubbers, exhaust ventilation, and air quality monitoring.
Question Number  42:   Per the contract documents LD’s are from NTP can that be re-worded to say from start of construction, as there will need to be time up front from NTP for submittals, planning and reviews and that will create problems in finishing up the vault in the 110 day time frame?
    Answer:   Addendum 1 is to revise the project duration originally stated in SC-7 Prosecution and Completion of the Work.
Question Number  43:   We understand that there may be chemicals settling underneath the transformer vaults from the de-icing process, that is unseen, will DEN be responsible for the hazmat removal if encountered?
    Answer:   At this time, environmental sampling has not detected de-icing chemicals in the water infiltration.
Question Number  44:   Can the staff or field staff assigned to work on this project also be the dedicated safety person?
    Answer:   See response to question 16.
Question Number  45:   Can the staff or field staff assigned to work on this project also be the dedicated QC person?
    Answer:   Refer to specifications for Contractor Quality Control requirements.
Question Number  46:   Per note 03 on demo drawings calls for a 3 hour TEMP barrier surrounding area of work during demo and construction, can we remove the 3 hour rating when referring to surrounding the area that is demoed, due to the obstructions in our way by baggage conveyors and mechanical duct makes it impossible to maintain a 3 hour temp barrier?
    Answer:   See response to question #15.
Question Number  47:   What is DEN anticipated start date, none was provided in the project manual and/or specifications?
    Answer:   The anticipated start is approximately the first quarter of 2020.
Question Number  48:   Are we to include in our bid the housekeeping pads for the cabinets on the tarmac or is that assumed by Xcel?
    Answer:   Housekeeping pads for switch cabinets on the Apron level are not within project scope.
Question Number  49:   Please verify which vaults have lines fed from overhead (above) and which vaults are fed from below slab?
    Answer:   Center core vaults have primary conductors overhead. Vaults in subcores have primary conductors routed from below slab. Secondary conductors are all routed overhead.
Question Number  50:   Does the Xcel coordination/phasing count against the 110 days, if so how many days do they need? Given the GC has no contractual relationship with Xcel for their portion of the work, if Xcel does not meet the agreed to, coordinated schedule please confirm this is grounds for a day for day schedule extension.
    Answer:   Coordination of work to be performed by Xcel Energy should be included in the construction schedule, as coordinated through DEN. Please note, schedule extentions are not to be assumed.
Question Number  51:   In order to maintain a temp separation inside the vault a temp wall can the clearance requirements surrounding live transformers be relaxed during adjacent construction?
    Answer:   See response to question #15.
Question Number  52:   Without a soils report, are we to assume that we will not encounter groundwater?
    Answer:   See response to question #20.
Question Number  53:   Can exhaust from equipment be vented through existing mechanical duct?
    Answer:   See response to question #41.
Question Number  54:   Please provide an assumed depth of caissons for bidding and schedule purposes as the documents reference a minimum depth only.
    Answer:   See response to question #20.
Question Number  55:   Can we use area by Concourse C to stockpile excavated dirt and spoils?
    Answer:   Excavated materials must be taken to the North or South recycle yards on the DEN campus. This will need to be coordinated with DEN project manager in advance.
Question Number  56:   Does each Vault location need a separate permit for building and MEP?
    Answer:   Permitting is done by address at DEN. All of Concouse B has a single address. Each discipline will also be required to obtain the appropriate permits.
Question Number  57:   At the jobsite walk Xcel said they could take down 2 vaults at a time providing access to one half of the vault room for construction, is this correct?
    Answer:   DEN's preference, in the case it is required to work on multiple vaults at the same time, would be to work on the different substation sources. The Contractor will need to coordinate in advance with DEN Tactical Planning and Operations to ensure construction activities do not adversely impact DEN and Airline Operations.
Question Number  58:   Some of the Sub-trades are currently enrolled in ROCIP program for the Great Hall Project. Will that status transfer over to this ROCIP project or do they need to start from scratch with enrollment application, drug tests, etc.?
    Answer:   Enrollment status is not transferable. All contractors are required to enroll in the project-specific insurance program. See DEN ROCIP III insturance manual for further details.
Question Number  59:   Will removal of the old overhead baggage transfer system (e.g. keynote 2 on A153) be performed by the GC or will DEN have that removed before start of this project?
    Answer:   Abandoned baggage handling system is to removed by the Contractor.
Question Number  60:   Are there any noise and/or vibration restrictions for demolition to consider?
    Answer:   See response to question #24.
Question Number  61:   Are there work hour restrictions for load-in and load-out of material?
    Answer:   See response to question #24.
Question Number  62:   During the Pre-Bid Walk, in Area 8W there is an existing Cap Slab that is not shown in the drawings with Existing Baggage Equipment being supported by the structure. Will this Baggage Equipment be removed prior to NTP for this project? Has it been determined that this Cap Slab is structurally stable to be shored for re-use?
    Answer:   The cap slab over the existing switch cabinet spaces within the vault is to be removed by the contractor. Existing BHS equipment is suspended from structure above. Existing BHS equipment is to be removed by the contractor.
Question Number  63:   During the Pre-Bid Walk, in multiple areas there is New Baggage equipment being supported by the CMU walls that will be demoed/rebuilt. Is there an issue with changing the design to hangers to support the new equipment instead of it being supported by the CMU wall? Will this be an issue with modifying new equipment while a separate project is undergoing current construction?
    Answer:   Temporary or permenant changes to support new Baggage Handling System will need to be coordinated through DEN.
Question Number  64:   The demo drawings for Area 8W show to remove the floor, but doesn’t show to replace these areas in the drawings with a new concrete floor. Will there need to be finished flooring in these areas where not shown to place back? If the slab is to remain, provide a detail how we leave the existing surface after we remove the masonry wall.
    Answer:   All areas of flooring to be removed must be replaced; see structural details for slab-on-grade requirements.
Question Number  65:   Is it acceptable to use CNG equipment in all of the construction areas for this project?
    Answer:   It is acceptable to use CNG equipment in the basement level of Concourse B and outside the building.
Question Number  66:   Where are the designated Access/Laydown areas for this project? Where are the designated parking areas for the project?
    Answer:   Laydown area and parking will have to be coordinated with DEN after award.
Question Number  67:   What are the Painting Limits? It seems clear that the interior of the new rooms paint, however is any painting anticipated on the exterior of the Vaults.
    Answer:   Painting is specified only for the interior surfaces of the vaults.
Question Number  68:   Please provide a Geotechnical Report
    Answer:   The geotechnical report is provided in Addendum 1.
Question Number  69:   The documents are clear on the minimum requirements of Drilled Piers. Would DEN consider adding additive or deductive unit prices to the Bid Form for over or underruns of Drilled Pier quanities?
    Answer:   DEN does not elect to change the bid form to address this.