Blackwater Dam Concrete Repairs in Webster, New Hampshire

Scope of the repairs for Blackwater Dam includes:? Inlet nosing at conduit entrances: Remove deteriorated FRP liner, remove existing concrete to sound concrete (4? deep nominal), install rebar anchors and welded wire fabric reinforcing, and apply polymer modified concrete thick patch (4 nosing total).? Flow control conduits (3 conduits): Remove deteriorated FRP surface liner on all surfaces of the conduits. Apply 2? thick polymer concrete patch upon removal of existing concrete on all walls and floor surfaces.

As needed, patch only on spalled areas concrete at the ceiling surface upon removal of the liner.? Spillway apron downstream of the conduit: Remove deteriorated FRP liners and apply, as needed, patch to spalled concrete surfaces.? Work in the conduit area will require a phased temporary flow diversion structure to direct stream flow to a single open conduit while working on two that are kept dry during the low flow construction window.

Based on the construction window with historically the low water season for the year, the Government anticipates concrete removal for repair works inside the conduits by hydro-demolition with associated pumping and waste treatment self-contained mechanical units.? At the non-overflow sections of the dam, work consists of removal of previously patched areas that are deteriorating and applying new polymer concrete patches to be followed by the application of penetrating sealer to the exposed concrete area.

In-water works will be conducted during low flow water period of Summer of 2024.The clauses at 52.236-2, Differing Site Conditions, and 52.236-3, Site Investigations and Conditions Affecting the Work, will be included in any contract awarded as a result of this solicitation.

Accordingly, offerors or quoters are urged and expected to inspect the site where the work will be performed.An organized site visit has been scheduled for January 29, 2024 at 10:00 AM ETParticipants will meet at Blackwater Dam, 43 White Plains Road, Webster, NH 03303