HMSG Design for Building Envelope Repairs RFI 2020-09-11.pdf

No. Question Response

196 Reference E1-A-601 - A-601 has a schedule of insulation thicknesses that depends on the cavity depth. The insulation specs reference the drawing thicknesses for R-4 per inch. What is the desired R-

Value independent of the cavity depth?

R-16 is the desired R-value independent of cavity depth. E1-A-601 indicates acceptable insulation thickness where the desired R-value is not achieveable.

197 Drawing E1 A103 “Architectural New Work Floor

Plan.”CPT-1 (Interface) is call out on the Interior

Finish Schedule, please provide color,and item number.

Basis of Design: Interface Menagerie II, Color TBD

198 Please confirm no rubber base or transitions will be required for the Lerner

Room. If required, please provide a specifications.

Confirmed, there is no rubber base. The existing plaster continues to the Ardex floor and is caulked.

199 Please confirm the highlighted-attached HVAC scope of work is existing and not to be included in our bid submission

Confirmed, Elevator Machine room HVAC and associated systems indicated on sheets E1 M-010, E1 M-

011 are not in scope.

200 Please confirm that the wedge inserts for the existing precast panels do not need to be removed.

Silman recommends cleaning off any corrosion, applying a corrosion inhibitor, filling with epoxy grout and leaving the wedge inserts.

201 If the bolts for the precast inserts are frozen in place, are we allowed to burn them out as long As they are removed greater than ½ inch prior to being grouted back with corrosion inhibiting grout.

The approach of cutting out bolts to a depth that allows grout to cover it is acceptable. The depth of cutout needs to be coordinated with the grout product minimim thickness.

202 Please reference Paragraph 1.H of Section 034500 regarding testing requirements for precast architectural concrete. Section 1.H.1.c requires the contractor to field test not less than 20% of the attachment anchors. We have been advised by our precast subcontractors that this quantity is excessive and not in line with industry standard.

Please consider reducing the quantity of field tests to a more reasonable amount (i.e. 5% of the attachment anchors).

The application for this project is a horizontally oriented adhesive anchor with sustained tension, which is more susceptible to failure and is why IBC and ACI require continuous inspections for these anchors.

Based on the application and location of the panels

20% testing is required.

203 Clarification is needed for RFI #21: After the precast panel supports and bolts are removed, will there be an anchor sleeve still remaining embedded in the concrete structure (drum)? If yes, does the anchor sleeve need to be removed by core drilling or should we leave the anchor sleeve embedded in the structure?

See response to RFI 200.

204 If the anchor sleeves show signs of corrosion, are we to try to remove the corrosion before continuing with the corrosion inhibitor and grout?

See response to RFI 200.

1821115 - HMSG Design for Building Envelope Repairs RFI Response

205 The bid form indicates to provide separate pricing for ‘Submission and Smithsonian Approval of

Coordination Drawings as defined in Section

01000,’ ‘Submission and Smithsonian Approval of

Record Submittals as defined in Section 01000,’ and ‘Submission and Smithsonian Approval of

Operation and Maintenance Manuals as defined in Section 01000.’ Should these amounts also be included in the base bid total above?

They both are line items to be included in the total.

206 Specification section 034500, section “H.

Preconstruction Testing”, item 3.2 states twenty percent of testing of attachment anchors is required. Item 3.e states providing three field tested samples for all types of anchor bolts post-installed. Our understanding is that all bolts are post-installed. Please advise what quantity of testing is required for permanent installations.

Silman: Refer to Silman response to RFI 202 for discussion of testing of standard post installed anchors into the existing concrete. The 3.e testing is not for the standard post installed anchors into the existing concrete. It is for the different attachment methods ultimately developed and designed by the contractor for the attachment to thin precast panel. The design drawings show one option that has an embed plate in the panel with threaded inserts for looping reinfrocing through, which would result in one group of three samples. The number of groups of testing for this anchorage will be based on the number of different types the final design by the contractor comes up with.

207 Spec Section 034500 states that connections for precast panels are to be fabricated and installed as hot dipped galvanized steel. Structural drawings state stainless steel components are the intended material. Hot dipped galvanized anchors would result in a substantial cost savings over stainless steel. Please advise which material the clips/attachments for precast panels are to be made from.

Hot dipped galvanized or stainless steel connections are structurally acceptable. Precast panels connections are a delegated design item. Note that some components may need to be stainless steel based on availability or meeting performance requirements.

208 Section 2.4 within specification section 010000 calls for Contractor to “furnish full engineering services” for 034500- Precast Architectural

Concrete. Please confirm the precast panel connection details as shown in the drawings are suggested details, and that it is the responsibility of the Contractor to design the connection details to meet the performance criteria specified in the drawings.

Confirmed.

209 Section 072100, page 3/8, 2.1: The specifications define the cavity wall insulation to be mineral wool, with and R value of R-4 per 1” of thickness.

In the HMSG Envelop Repairs “Basis of Design” document, page 4, the design team has decided to move the new face of PCC wall out 3” from existing to accommodate the waterproofing and new cavity wall insulation. Please confirm the minimum thickness of new mineral wool insulation and expected minimum R value to be provided.

Minimum thickness of insulation shall be 2" with minimum R-value of 8 per E1-A-601.

210 In reviewing the specifications and contract drawings, the drawings define the exterior joint sealant between PCC panels to be 3/8”, but specification section 034500.3.3.B.3 defines the permissible joint size to range from 3/8” to 5/8”.

Is it acceptable to design the panel to panel joint at ½” width vs 3/8” ? The PCI PCC manufacturing tolerances are 1/8” plus and minus, and the sealant manufacturers will only warrant a minimum ¼” joint, so by designing the joint size to be ½”, we can absorb the PCI manufacturer face dimension tolerance both (+ and -) and not create a joint less than 3/8”, further the sealant warranty will not be compromised.

Confirmed, this is acceptable. Joint sizes to be within

3/8" and 5/8".

211 We understand there to be a restriction to have the roofer’s “hotpot” or “kettle” located on the roof because of a fire hazard risk, but having the kettle located on the ground creates complications with the hot rubber becoming too cold because of the time it take for buckets to get from ground level to the roof. Would it be acceptable to locate the kettle at or near the top level of the scaffolding?

Yes, if located safely off the roof, it will be considered.

212 We understand there to be a restriction to have the roofer’s “hotpot” or “kettle” located on the roof because of a fire hazard risk, but having the kettle located on the ground creates complications with the hot rubber becoming too cold because of the time it take for buckets to get from ground level to the roof. Would it be acceptable to sit an electric powered “melter” (no open flame) on the roof?

Yes, it will be considered.

213 The drawings call for cast-in-place concrete curbs on the roof to support the RTU’s. The hot rubberized asphalt requires a minimum of 28-day concrete cure time prior to installation. Would the

Smithsonian consider an alternate to use prefabricated metal curbs in lieu of cast-in-place concrete?

Metal curbs in lieu of cast-in-place concrete for the roof top units supports are not acceptable.

214 The site logistics plan that was shared on the

YouTube solicitation/virtual walk through video indicates a 30x30 location for a crane at Jefferson drive, lapping onto the sidewalk. Drawing AS-002 shows a limit of fencing which is [scaled] less than thirty (30) feet off of the tall existing planter. Per field measurements taken by our team: the sidewalk is fifteen (15) feet wide, and the first lane of traffic is eleven 11) feet wide. Addendum 02, RFI 32 Response, indicating leaving one lane for emergency vehicles and maintaining current parking. Is it acceptable to take the middle lane to the east of crosswalk on Jefferson Dr. to accommodate the needed space for the project’s equipment?

Leave one lane for emergency vehicles and maintain current parking.

215 Concrete Repairs(section 039320) and Hot Applied

Roofing spec (section 075556) indicates that new crickets are to be installed at the roof to create positive drainage on the roof. New concrete crickets will require a period of time for the concrete to cure, which means a temporary roof would be required which increases the chances of leaks and would be more costly. Would the

Smithsonian consider a roofing system for RF-01 that leaves the structural slab as is (unless in need of a repair) and is comprised of (from bottom up) hot rubberized asphalt, protection board, drainage composite, TAPERED (in lieu of straight) polystyrene insulation, and TPO (in lieu of filter fabric) and pavers? TPO would be a premium over filter fabric, but it would eliminate the need for significant temporary roofing and decrease the chances of leaks. It would also allow for a full roof survey after the hot rubber is placed as opposed to a section by section survey as the roof gets demolished.

Crickets are only intended to be installed near elevator overrun, refer to E1 A-105. Provide crickets as shown.

Tapered insulation is not required or desired, because it will affect paver height and because drainage should occur in the plane of primary waterproofing (i.e. at the

Hot Applied Roofing on the structural concrete deck).

Use of TPO would turn assembly into an exposed roof with ballast, whereas design team and SI weighed pros/cons of such a system early in design phase and chose a protected membrane assembly. Provide RF-01 assembly as shown in contract documents.

216 The latest bid sheet provided in Addendum No. 5 requests breakout costs for Coordinated

Drawings, Record Submittals, and Operation and

Maintenance Manuals as defined in Section

010000. It asks for these as “separate pricing”.

Does this mean that these costs should NOT be included in the base bid?

See RFI #205. They both are line items to be included in the total.

217 The specifications indicate commissioning is required, however, due to the lack of a Sequence of Operations/ controls sequence specifications we infer that each new system is considered

‘standalone’ which would require a check out via in-house commissioning agent and any existing systems would be returned to their original state(whether tied into a BAS or not). Please confirm that a traditional commissioning process is not required.

Confirmed, this is not a traditional Cx process for existing equipment. The sequence of operations for

AHU-1 will be supplied to the GC and the equipment will need to be returned to its existing state.

Commissioning is required for the heating integrated into the curtain wall.

218 Would the Smithsonian object to off-hour deliveries/off-loads coming in and out of

Independence Avenue as long as there was no temporary fencing taking up more of the plaza than what is shown on drawing AS-002?

No.

219 Would the Smithsonian object to off-hour deliveries/off-loads coming through the inner courtyard of the plaza as long as there was no temporary fencing remaining there during business hours and as long as the plaza is properly protected?

No, but should be coordinated with COTR.

220 Section 4.1 of specification 010000 says “The base bid for the proposal shall assume the precast panels will be installed using panel connections and insulation depth to accommodate the largest potential offset of 9 inches.” Is this 9 inches assumed to be from face of structural drum to the inside face of the the new precast panels or the outside face?

The 9" is assumed from the face of the structural drum to the inside face of the new precast panels.

221 Specification section 075556, 1.9.D states that the

ELD testing firm is to be approved by the COTR.

Typically, Honza Group & International Leak

Detection (ILD) are the primary vendors in this area. Are these acceptable testing firms for this project?

Provide their qualifications. They need to fulfill project requirements.

222 Mast climbers are not necessarily conducive to support scrim. Please confirm that if the

Contractor chooses mast climbers for means and methods, scrim will still be required.

Scrim is required.