Location
United States / Americas
Project record
Upper Mississippi Lock and Dam 9 miter-gate replacement
Federal navigation crews replaced all four main-chamber miter gates at Lock and Dam 9 near Lynxville, Wisconsin, in July 2026. G&G Steel of Russellville, Alabama, fabricated the gates over about two years; they then moved by barge to the site. St. Paul District's maintenance and repair crew installed them with Rock Island District personnel and the 500-ton heavy-lift crane The Quad Cities. The four-day installation completed a four-to-five-year USACE design and delivery effort, but the public sources do not disclose G&G Steel's fabrication-contract value, fabrication subtiers, transport contracting, accepted installation cost or final account.
Segment
Inland navigation lock rehabilitation and hydraulic steel structures
Status
USACE reports that all four main-chamber miter gates were replaced in July 2026 by St. Paul and Rock Island District maintenance and repair crews; G&G Steel fabricated the gates in Alabama, while accepted installation cost, final account and post-installation performance remain unpublished / Confirmed
Last checked
11 August 2026
Coverage
Related sectors
Inland navigation lock rehabilitation and hydraulic steel structures is the primary work classification. Related sectors connect this record to adjacent marine delivery and market coverage.
Subject index
Related subjects
These subject pages bring together related projects, technical articles, reports, and evidence methods.
Project anatomy
Contract scope and delivery roles
- Client / authority
- U.S. Army Corps of Engineers, St. Paul District, with Rock Island District delivery support
- Delivery parties
- G&G Steel, Inc. - confirmed fabricator of the Lock and Dam 9 miter gates in Russellville, Alabama, USACE St. Paul District maintenance and repair crew - field installation team named by USACE, USACE Rock Island District maintenance and repair personnel - joint installation support and operator of the 500-ton heavy-lift crane The Quad Cities, Fabrication subtiers, coating suppliers, barge transport contractor and other private lower tiers - not identified in the cited public records
- Contract route
- USACE's project page identifies G&G Steel as fabricator but does not publish the fabrication solicitation, award identifier, contract value, competition record, delivery terms or modification history. The same page separately allocates fiscal-year 2026 funding of USD 1.5 million for the Lock and Dam 9 anchorage upgrade and USD 1.25 million for miter-gate installation. The completion story states that USACE professionals supervised construction and contracting and that USACE crews performed installation; neither source establishes a private installation award.
- Execution window
- The gates took approximately two years to fabricate in Alabama and were transported by barge to Wisconsin. USACE scheduled 12-hour lock closures on 14, 16, 21 and 23 July 2026 to replace all four gates, then reported the four-day installation complete on 11 August. The broader design-to-install effort lasted four to five years. Public sources do not disclose the fabrication notice to proceed, gate delivery date, post-installation acceptance date, defects period or final commercial close-out.
- Works package
- The completed package replaced two upstream and two downstream miter-gate leaves in the main lock chamber and upgraded the anchorages and pin plates supporting the heavier gates. USACE states that the new gates retain the original length, width and height but are about 50% heavier, were designed to modern codes using current ice and current knowledge, and carry a nominal 50-year design life. Published records do not provide dimensions, steel tonnage, coating system, bearing details, seal manufacturer, hydraulic or electrical modifications, testing criteria or as-built drawings.
- Marine interfaces
- Delivery combined inland-waterway heavy fabrication, barge transport, controlled commercial-navigation closures, removal and lifting of four large steel leaves, anchorage work and recommissioning inside an operating nine-foot navigation system. Rock Island District's 500-ton floating crane The Quad Cities was the named heavy-lift asset. The closures protected both commercial and recreational traffic, but no cited record identifies towage, rigging, diving, survey, temporary works or gate-component suppliers.
- Commercial evidence boundary
- USD 1.5 million for the anchorage upgrade and USD 1.25 million for gate installation are USACE fiscal-year 2026 funding lines. They do not disclose G&G Steel's fabrication award, actual obligations, internal force-account cost, transport price, accepted quantities, variations or final account. No cited public source assigns a private installation contractor or names fabrication subcontracts; reporting G&G Steel as installer would therefore be incorrect.
Contract and delivery chain
Named roles and open packages
Named appointments are shown against the workstream they cover. Unallocated packages remain open until a project source identifies the responsible party.
Gate fabrication
Four main-chamber miter-gate leaves
- Named party
- G&G Steel, Inc.
- Status
- Confirmed
- Source position
- USACE names G&G Steel of Russellville, Alabama, as fabricator; the completion story says fabrication took approximately two years before barge transport to Wisconsin. Source
Anchorage preparation
Anchorage and pin-plate upgrades for heavier gates
- Named party
- USACE St. Paul and Rock Island District maintenance and repair teams
- Status
- Confirmed
- Source position
- USACE's programme page explains the anchorage and pin-plate work and assigns USD 1.5 million in fiscal-year 2026 funding; the cited records do not identify a private contractor. Source
Heavy-lift installation
Removal and replacement of four main-chamber miter gates
- Named party
- USACE St. Paul and Rock Island District maintenance and repair crews
- Status
- Confirmed
- Source position
- USACE reports a completed four-day installation using Rock Island District's 500-ton heavy-lift crane The Quad Cities. Source
Commercial close-out
Fabrication award, actual installation cost, variations and final account
- Named party
- USACE and G&G Steel
- Status
- Not evidenced
- Source position
- The official sources publish fiscal-year funding and role allocation but no fabrication-contract value, accepted force-account cost, subcontract ledger or final account.
Project timeline
Material developments
Dated events that changed scope, counterparties, delivery, commissioning or operating status.
Open this project in the Change LogUSACE reports four-gate installation complete
The project moves from scheduled summer work to reported physical completion, with the two-district USACE installation team and heavy-lift asset now public.
SourceFourth planned 12-hour lock closure
The last planned closure completed the published four-date installation sequence; the 11 August USACE story later confirmed physical completion of all four replacements.
SourceUSACE publishes fabricator and fiscal-year funding baseline
G&G Steel is fixed as gate fabricator while USD 1.5 million anchorage and USD 1.25 million installation lines remain separate public funding baselines.
SourceEvidence gap
What remains unverified
Outstanding evidence
- G&G Steel fabrication award identifier, value and modification history
- Gate dimensions, steel tonnage, coating, seals and acceptance testing
- Named fabrication suppliers and private lower tiers
- Barge transport, towage, rigging, diving and survey responsibility
- Actual cost against USD 1.5 million anchorage and USD 1.25 million installation funding
- Post-installation testing, acceptance and defects close-out
- Navigation availability and maintenance after the first operating season
- Ice-season inspection and long-term 50-year design-life performance
Sources and related records
Read featured analysis Methodology Submit a correction Project tracker
Source collections
Project sources 4
- Stronger gates, stronger river: Lock and Dam 9 upgrade secures Upper Mississippi Navigation U.S. Army Corps of Engineers, St. Paul District via DVIDS, 11 August 2026
- Navigation: Mississippi River Locks and Dams 2-10, Miter Gate Replacements U.S. Army Corps of Engineers, St. Paul District, 25 March 2026
- Corps of Engineers announces temporary closures at Lock and Dam 9 U.S. Army Corps of Engineers, St. Paul District via DVIDS, 1 July 2026
- Lock and Dam 9 gate replacement field photograph U.S. Army Corps of Engineers, St. Paul District via DVIDS, Photographed 21 July 2026; posted 11 August 2026