Cannon_Bid_Question_Response.pdf

FA4855-15-B-0009

REPAIR ROADWAY SECTIONS AROUND E. ADERHOLT LOOP

QUESTIONS

1. By the requirements of Specification Section 31 05 21 – Geogrid Soil Reinforcement the properties listed call for the use of a uniaxial strength geogrid, rather than a biaxial or triaxial strength geogrid. Is it the intention of the specification to require a uniaxial strength geogrid on this project? No, the geogrid soil reinforcement should be a triaxial Geogrid. The installation, including the overlap, should be done in accordance with the manufacturer’s recommendation.

More information: Uniaxial geogrids have primary strength in the machine direction and negligible strength in the cross machine direction. Uniaxial geogrids are most often used for grade separation applications, such as retaining walls and reinforced soil slopes. While the term uniaxial geogrid is not used in the specification, requirements for Allowable Tensile Strength, UV Resistance and Coefficient of Interaction for Pullout are all properties commonly used for uniaxial geogrids and not biaxial or triaxial geogrids. Additionally, reference is made to the fill in the reinforced zone, which is terminology used for Mechanically Stabilized Earth structures, such as retaining walls and reinforced soil slopes, where uniaxial geogrids are most often used.

Biaxial or triaxial geogrids are most often used in roadway applications, either below or within the base course, as indicated on this project. Biaxial or triaxial geogrids have primary dimensional strength or primary strength in multiple directions. When biaxial or triaxial geogrids are installed, adjacent rolls are overlapped and in some instances fastened to secure the overlap, this is different from what is indicated in the execution section of the specification.

Lastly, splices and penetrations are not typically used in biaxial or triaxial geogrid installations, as indicated in the execution section of the specification where a reference is made to a slope.

2. What are the limits of seeding? Seeding will be required for all disturbed areas outside of the paving limits.

3. Will seeding be rquired on Afterburner Rd.? Seeding will be required on Afterburner Road, where existing vegetation is disturbed. Generally speaking that will cover the east two-thirds of Afterburner Road as much of the west 1/3 is either paved or has access roads connecting into Afterburner Road. The exact limits should be verified in the field.

4. The plans indicate a tack coat between lifts, will the tack be required in all instances? Yes, the tack coat will be required in all instances.

5. Is there a limit on the length of the work zones? The contractor will submit a phasing plan that will include the length of the work zone to the Contracting Officer for approval. The contractor will need to take into account the how the traffic will queue during flagging operations during the day, and self queueing at night to determine the best length.

6. On Plan sheet C-001, typical Section 3, the note on the existing Base states to add new base material to bring the roadway profile to grade. Has this quantity of new material been determined and if so is it available? No, this quantity should be calculated by using the spot elevation plans to compare existing and proposed elevations.

7. On Plan sheet C-001, typical Section 3, the note on the existing Base states to add new base material to bring the roadway profile to grade. In reviewing the spot elevations on the CG plan sheets it appears that there will be locations where over 3" of existing base will be removed.

The note on Plan sheet C-001 states that the overall base thickness should be 8". Is the depth of the existing base course sufficient in the locations where the profile grade is lowered and base is removed to maintain the desired 8" of depth? Based on information provided by Cannon AFB, it is believed the existing base course is at least 8”’s in depth. The existing curves show an uneven cross-slope in the superelevation. The intent of the design is to create a consistent, smooth cross-slope through the curves. If, during construction, it is discovered the existing base does not have the required depth, the spot elevations and cross-slopes may need to be adjusted to meet that requirement.

8. Are the pavement markings single or double application? The NMDOT requires Double application currently. The intent is to follow all NMDOT pavement marking requirements.

9. Will temporary striping be required to be installed before striping is done? The NMDOT allows the use of temporary marking tabs per the attached drawing, will temporary tabs be acceptable in lieu of painting at half application rate? Yes, temporary striping will be required. The use of temporary marking tabs will be acceptable.

10. Is there a preliminary SWPPP Plan available for bidding purposes? A SWPPP plan has not been developed.

11. The plans indicate that Prime Coat may be required. Will Prime be required on the processed and new base course? Per specification section 3.4.2 of Spec 32 12 10, the prime coat is required if it will be at least 7 days before the surfacing layer is constructed on the underlying compacted material. See specifications for further information.

12. General Note 8. On plan sheet GI-002 states that Borrow will be obtained off base. Will borrow be required on the project? If so, is there and estimated earthwork summary available for bidding purposes? It is not anticipated that borrow will be required. If, however, during the course of construction borrow would be needed for an unforeseen circumstance, it would need to meet the requirements of note 8 and the earthwork specification.

13. There are three driveways shown on plans sheet CP-115 that are designated for new pavement.

These drives are not shown on plan Sheet CD-106 as requiring demolition work. Please clarify the limits of construction for these three driveways. Currently, all three drives are gravel. The limits of construction would be to remove the gravel for the returns shown, pave the returns and re-grade the existing gravel drive to tie into the new paved return.