Questions for Contractors - Guajataca Dam - Industry Outreach.pdf

Guajataca Dam Permanent Repair Project

Industry Outreach Questions

NOTE TO CONTRACTORS: The Government reserves the option to schedule follow-up meetings when additional discussion would materially improve acquisition planning. In addition, this information exchange is strictly for market research purposes. It does not constitute a request for proposals or authorize potential offerors to perform design work or incur any costs. The government will not reimburse contractors for expenses incurred in responding to these questions.

Description – The Government requests input on potential constructability concerns and limitations for the Guajataca Dam Permanent Repair Project. Contractors are encouraged to discuss the questions below during the Industry Outreach event (July 28 and 29, 2026) and the virtual one-on-one breakout sessions scheduled for August 4–7, 2026. Contractors are also encouraged to provide written responses to these questions prior to the end of August 14, 2026. Responses may be sent to Ms. Renee Booth at meranda.r.booth@usace.army.mil and

Ms. Ronica Smith at Ronica.r.smith@usace.army.mil. If you are submitting information that is proprietary in nature, please clearly mark the applicable documents or sections as Proprietary.

The Government will protect properly marked proprietary information and will not share it with other contractors or suppliers.

Scope of Work – This event will discuss two separate potential contract actions. The primary purpose is to solicit feedback from the construction industry, specifically targeting contractors with expertise in deep soil mixing (DSM), deep mixing methods (DMM), concrete diaphragm walls (panel or secant pile construction), grouting, and other innovative soil improvement techniques for seismic remediation of a hydraulic fill dam with a very soft puddle clay core.

Guajataca Dam Early Work Effort (Potential Contract 1) – This contract includes but is not limited to utility (electrical, telecommunications, water, and sewer) relocations, administrative office building demolition and relocation, traffic report and detour route, left abutment water supply siphon system, and all incidental related work. All work affecting public roads, restricting public traffic, and involving utility relocations must comply with the Puerto Rico Highway and

Transportation Authority’s (PRHTA) standard specifications.

Guajataca Dam Permanent Repair Project (Potential Contract 2) – This contract includes construction repairs of several major features to address significant risks relating to: stoping of embankment material into karst and joint features in the right and left abutments, transverse cracking of the embankment due to seismic loading, seismic deformation and cyclic softening of the puddle core leading to crest lowering and overtopping, concentrated leak erosion (CLE) through transverse cracks across the embankment caused by landslide movement, cracking and scour of the grouted riprap spillway chute, and overtopping of the right side of the spillway causing embankment scour and stability failure. USACE is specifically seeking to engage with soil improvement, deep soil mixing, and grouting contractors to address key project challenges.

General Questions to Contractors

1. Risk Management

Dam crest degradation:

o What methods should be considered for degrading and restoring the crest?

o Should we consider limiting length of crest degradation to about 200-500 ft reaches?

o Temporary flood control measures to consider? Blocks or berms may be needed anyway for edge protection.

o Any concerns with bearing heavy equipment (cranes, cutoff wall equipment) on soft puddle core?

o Could emergency protection be implemented seasonally and/or before an anticipated spill event – and if so, how much warning may be needed and how much time would be needed to construct temporary measures?

o For the water supply siphon pipe at the left abutment, what considerations should be given to performing open excavation through the crest versus horizontal bore? How could leakage/seepage along the pipe from the reservoir be managed during construction?

2. Labor & Equipment Capacity

What heavy equipment (e.g., large-capacity cranes, heavy dump trucks, specialized soil compactors) is locally available, and what requires mobilization from the mainland?

3. Timeline & Milestones

What are the anticipated periods of performance for proposed Contract 1, assuming a

Design-Build (DB) delivery method, and proposed Contract 2, assuming either a DB, traditional design-bid-build (DBB) or Early Contractor Involvement (ECI)/ Integrated Design and Construction (IDaC) acquisition strategy?

Assuming the DB contract is awarded for Potential Contract 1 in the third or fourth quarter of next year, what key considerations and sequencing concerns should industry communicate to USACE in coordination with Potential Contract 2?

4. Construction Sequencing

How would working during the rainy season affect contractor production rates? June-Nov is hurricane season.

What approach would you take to constructing in an active spillway. The spillway is required to be operational during construction. Spillway activation recurrence frequency of 1/3 years.

5. Cost & Schedule / Contract Type

How can innovation and competitive pricing be encouraged and valued in alternative delivery such as DB and/or utilizing Early Contractor Involvement?

6. Contractor Capabilities

Potential resource constraints? What resources (equipment/materials/parts) will be a challenge to procure and have available at Guajataca? What potential delays would you expect? What resources are available to your team within the local vicinity of the project?

How could procuring mainland equipment and materials be expedited reducing risk for complications and delay?

7. Constructability

Wall Method & Feasibility o How feasible would removal of the reinforced concrete key wall be at the base of the dam during DMM installation? Given the nature of hydraulic fill embankments, how would large debris within the embankment affect DMM installation?

o Given the complex abutment geology (landslide material, karst limestone, soft marls/claystones), is Deep Soil Mixing (DSM/DMM) ideal, or are alternative barrier methods better?

o Are there geometric or depth limitations with your recommended construction method?

o Are there concerns using DSM in the soft CL-CH clay puddle core or heavy clay foundation rock?

o Do you have case studies of DMM walls constructed in dams or levees with soft, hydraulically sluiced clay cores?

o How should strength objectives be verified within improved core zone?

o Are there any special considerations that should be considered for monitoring embankment deformation during construction?

Grouting & Pre-Drilling Requirements o Will pre-drilling be required in the bedrock (100–3,000 psi limestone/marls/claystones)?

o Is pre-grouting necessary for DSM or alternative wall methods? What are the risks of omitting it?

o How can we protect the embankment from grout breakouts during grouting?

o Right Abutment (Tunnel): What are the best practices, risks, and optimal sequencing for radial grouting from inside the 1920s concrete horseshoe tunnel to tie in the cutoff wall?

o How can grout pressures be managed to minimize impacts to the outlet works tunnel?

Cutoffs at Abutment Structures o Left Abutment (Siphon): How do we ensure a positive cutoff around the new 42-inch

HDPE pipe and spillway approach walls where gaps in the cutoff wall/grouting may exist?

o Outage Timing: What is the expected outage duration for tunnel gravity discharges, and what are the minimum bypass flow requirements?

o What considerations should be given to tying in abutment cutoffs to the core stabilization wall?

Work Platform Requirements o What platform considerations are required for safe, continuous equipment operation?

o Does the platform require additional reinforcement/stabilization for heavy equipment loads?

o What factors determine whether the temporary platform can remain permanently vs.

being removed?

Construction Staging & Logistics o Sequencing: Should cutoff walls and grouting be installed simultaneously on both sides, or staged sequentially (e.g., left-to-right)?

o Footprint: What are the expected space and laydown area requirements?

o Spillway Integration: What access, staging, or sequencing issues should be considered regarding the spillway overlay and improvements?

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