PRELIMINARY AND FINAL DESIGN PROPOSAL-PHASE 2, 3 & 4
Scope of Services, Tasks, and Fee
Structural Engineering Services-Connector Ramp to the
Cotton Transfer Bridge at Cotton Mill Building, Nashua, NH
July 31, 2020
Scope of Services
Summary of Services:
Following is a summary of the professional engineering services required for Preliminary Design
(Phase 2}, 90% Design (Phase 3), and Final Design (Phase 4). Note that conceptual design
(Phase 1} has already been completed and submitted to the City: oo
1) Preliminary and Final Structural Engineering Design and Detailing of a Ramp from the
ground on the north side of the Nashua River at the Cotton Mill Apartment Building
connecting to the existing bridge spans.
2) Geotechnical explorations with Preliminary and Final Geotechnical Engineering
recommendations for the foundations to support the above-mentioned ramp.
The anticipated schedule is as follows:
« August 2020: Contract Executed/Notice-to-Proceed
e November 2020: Preliminary Plans and Estimaie for review assuming Survey is provided by
September 1, 2020.
e January 2021: 90% Plans, Specifications and Estimate for review
e March 2021: Final Design Documents
e Aprif2021: Project Advertisement
Phase 2—- Preliminary Ramp Design and Estimate
1. Address comments on Conceptual (Phase 1) recommendations.
2. Once survey is provided by the City, VHB will confirm the ramp layout shown in the conceptual
ramp plans and adjust the ramp as needed to meet the existing grade of the project site. The
ramp willbe ADA compliant.
3. VHB will coordinate with the Geotechnical Engineering subconsultant for geotechnical
explorations and to provide preliminary and final geotechnical recommends for the ramp
foundations.
4. VHB will perform preliminary design and detailing for the major ramp components. The ramp will
be designed in accordance with the 2009 AASHTO LRFD Guide Specification for the Design of
Pedestrian Bridge with 2015 interim Revisions and the 2020 AASHTO LRFD Bridge Design
Specifications, 9" Edition, as applicable.
5. VHB will develop two conceptual screen/fence alternatives on the north side of the ramp to
provide privacy for the building occupants. Preliminary costs for each alternative will be provided.
6. VHB will develop preliminary plans showing all the major elements of the ramp but will not include
fully developed details of all work elements. This phase will also identify ramp material type and
aesthetic details. lf possible, VHB will mimic the ramp material properties and aesthetics used on
the ramp on the south side of the cotton transfer pedestrian bridge, to maintain consistency.
7. VHB will develop a construction cost estimate based on major item quantities and NHDOT
average unit bid prices.
8. The VHB Project Manager / Program lead will perform a quality assurance review of the
preliminary plans and estimate.
9, VHB will prepare and submit preliminary ramp plans and estimate for review.
Phase 3 - 90% Ramp Design and Estimate
1. Address comments on Preliminary (Phase 2) recommendations.
2. Final coordination with the Geotechnical Engineer for final foundation recommendations.
