Questions_and_Answers.docx

Questions and Answers Amendment 2

The purpose of this amendment is as follows:

i. To extend to due date to 07/26/2018

ii. To post the following questions and answers.

1. Question: Loading Triangular Spreader Setup 5 x 4 rectangular tube may not be commercially available in the specified 3/8” wall thickness. Although 5 x 4 x 1/4 tube does appear to be available (consultation with steel suppliers will be necessary), it is assumed that your office will prefer 6 x 4 x 3/8 tube if the specified tube cannot be located. This will preserve (actually increase) the fabrication’s strength and stiffness. Can NIST please confirm our current assumption.

Response: 5x4x3/8 are available in the market. NIST could accept 6x4x3/8 as an alternative. However, that will affect other components such as the tubes (Item 5) will need to be 1” longer…etc…. A complete new set of drawings have to be submitted to NIST for final revision and approval.

2. Question: Swivel A with Top Bearing Plate Will the cross beam (item 1) supported by swivels (item 3) be restrained by any additional braces or guides that are not shown on the drawings? If not, the swivels (item 3) will be loaded in compression and the beam assembly will be able to “flop over” in an undesirable (potentially harmful) manner. (The arrangement is currently analogous to a broomstick being balanced on an upward facing palm. Without active control, a broomstick cannot balance itself and flops over.) Once the cross beam and swivels “flop over” and assume a stable position, the swivels will no longer provide the desired swiveling action. If the system configuration allows, the test facility might consider relocating the swivels (item 3) to the undersides of the triangular spreader assemblies so the cross beam is suspended from above and the swivels (item 3) are loaded in tension. If this conceptualized design change introduces an interference with the structures that are to be tested, the triangle spreader design might need to be substantially reconfigured or modified. The solicitation specification and drawings do not provide sufficient information for bidders to design (and budget upon) appropriately modified triangular spreader assemblies. (Details of the structures to be tested are not presently available to the bidders so they cannot now suggest or quote appropriately configured triangular spreader assemblies that eliminate the “flopping” concern.) NIST’s guidance on this concern and an appropriate bid due date extension are respectfully requested.

Response: Engineers at NIST believe that the current design is stable for the purpose of these tests. However, other alternatives would be considered as long as all components are modified accordingly, and detailed design calculations and drawings are provided to NIST for revision and approval. These loading systems will be used for multiple test configurations. The intention is to load flat surfaces (like concrete slabs) with gravity loads using hydraulic actuators located underneath (in the basement).

3. Question: Swivels (bearings) typically carry both dynamic and static ratings. (Static ratings are always higher than dynamic ratings.) Is the specified 32 kip rating a minimum static or minimum dynamic rating requirement? Bearings (swivels) are typically de-rated at elevated temperatures. Can NIST advise the temperature at which the 32 kip requirement applies?

Response: Since loads will be applied slowly, static ratings are acceptable. The tests will be designed to keep the swivels thermally protected and below 50oC. Ambient temperature rating are acceptable.

4. Question: Do any material requirements apply to the swivels (bearings)? All steel swivels (bearings) typically require grease. Many designs incorporate seals to retain the grease and preclude/reduce contamination. Most self-lubricating swivels include PTFE in one form or another. The greases, elastomer seals, PTFE, and fiber reinforced polymers typically found in most swivel (bearing) designs limit their rated operating temperatures. Bearing options start to become limited at operating temperatures above 75° C. Temperatures above 130° - 150° C preclude all bearings with seals and most self-lubricating bearings. Sustained operating temperatures above 200° C usually necessitate custom/special bearings. Can NIST please provide operating temperature data and/or temperature rating requirements? Does NIST have any lubrication or swivel (bearing) design preferences/requirements? NIST’s guidance and an appropriate bid due date extension are respectfully requested.

Response: No specific material requirements, as long as the swivels are rated for the specified loads. The tests will be designed to keep the swivels thermally protected and below 50oC. Ambient temperature rating are acceptable. An example would be the MTS 249xx.M160 or similar.

5. Question: The current ±15° rotation requirement is relatively high for standard bearings/swivels. Although there are standard bearings (swivels) that meet (or exceed) this requirement, this relatively large range of motion significantly limits the selection of standard bearings that can be considered. This limitation, coupled with possible temperature, material, and bearing (swivel) type requirements may necessitate the use of custom and less cost-efficient products or designs. (This comment is offered in case the ±15° rotation requirement is less critical than other requirements and can be relaxed. It is appreciated, however, that the application may indeed require the full specified range of motion and cannot be relaxed.)

Response: As mentioned above, The tests will be designed to keep the swivels thermally protected and below 50oC. For the purpose of these tests, +/-15 rotation is required. Example is given above.

6. Question: If all six beams (item 1) require swivels, a quantity of 12 (vs. 8) parts may be required.

Response: Only 4 frames will be used in the initial tests. Thus, only 8 swivels are needed at this time.

7. Question: Swivel B with Rod End Receiver Please see notes B, C, and D above, which also apply to this swivel.

Response: See above.

8. Question: If all six beams (item 1) require swivels, a quantity of 6 (vs. 4) parts may be required.

Response: Only 4 frames will be used in the initial tests. Thus, only 4 swivels are needed at this time.

9. Question: Loading Tubes ASTM A500 rounds in the specified grade and size may not be readily available. May the supplier select alternative OD, wall, grade, or ASTM tube/pipe standard to meet the project’s requirements if the strength of the part (as presently specified/designed) is not compromised?

Response: That is acceptable, as long as the replacement tubes are similarly strong (or stronger), other Items are adjusted accordingly, and detailed specifications and drawings are provided to NIST for revision and approval.

10. Question: Couplers The 3” width of the hex bar flat shown on the drawing A9 corresponds to a hex bar size that is slightly larger than 5”. (Hex bar size is measured across opposing flats.) Hex bar stock of the minimum desired strength may not be readily available in sizes above 4”. May similar parts machined from round bar with localized machined wrench flats (vs. entirely hex-shaped parts) be proposed? (Hex-shaped parts consistent with the part shown on drawing A9 can be produced from oversized round or square bar. The extra machining that this will require will drive up the government’s costs.)

Response: That is acceptable, as long as the replacement couplers are similarly strong (or stronger), other Items are adjusted accordingly, and detailed specifications and drawings are provided to NIST for revision and approval

11. Question: Threaded Rods M27 x 2mm fine thread rod does not appear to be readily available in the specified grade (B7). To reduce cost, may similarly strong (or stronger) fine-thread parts (metric or imperial) be proposed (say 1.125 -12 UNF thread, for example) if appropriate matching changes are made to the mating parts (items 4 and 6). This will allow the threaded rods (item 7) to be machined from readily available threaded bar stock.

Response: That is acceptable, as long as the replacement bars are similarly strong (or stronger), other Items are adjusted accordingly, and detailed specifications and drawings are provided to NIST for revision and approval….NOTE: this item ties into the Swivel B, which needs to fit the chosen rod.

12. Question: Anchoring Columns Drawing B1 suggests that two (2) anchoring columns are required for each set of two (2) bracing modules. If this is correct, and all four specified bracing modules will be used simultaneously, should the quantity of Anchoring Columns be four (4) and not two (2)?

Response: The quantities specified are correct. No additional columns are needed. In real testing, two frames will attach to one column (not two) as the other side will attach to the tested specimen.

13. Question: Regarding the Project Schedule presented in Table 3 of the Statement of Work, can you clarify the schedule requirements for any necessary Shop Drawing rework? It is my interpretation that any rework and re-submittal of the Shop Drawings at the request of NIST would be required within 14 days of receipt of the request for rework from NIST. Can you please confirm if this correct?

Response: Yes

14. Question: The Place of Performance listed in FedBizOpps.gov is the NIST offices in Gaithersburg, Maryland. Can you please confirm if my firm, located in Ohio, would be able to work remotely and deliver the Shop Drawings electronically, as specified in the Statement of Work, and the finished assembly via a freight carrier?

Response: Yes, electronic submission of drawings is acceptable/ preferable. Freight carrier is fine, as long as arrangements will be done in the case of defective, unacceptable items that need further attention as stated in the SOW.

15. Question: The drawings show a quantity of (4) four reaction frames and it looks like (2) two get mounted to the Columns (Drawing C-1) The request only shows a quantity of (2) columns required. Are two (2) additional columns needed for the other reaction frames?

Response: No, the quantities specified are correct. No additional columns are needed. In real testing, two frames will attach to one column (not two) as the other side will attach to the tested specimen.