Dresden Island Lock & Dam Permanent Concrete Anchors | Illinois

City: Morris
State: Illinois
Owner:  U.S. Army Corps of Engineers
General Contractor: Alberici Constructors

Dresden Lock & Dam Permanent Concrete Anchors Project Background

In a joint effort, The US Army Corps of Engineers along with agencies embarked on a project to restore the Illinois River Basin, after it had experienced issues such as sedimentation and increased water level fluctuations due to time and human activities. This structure, built in 1933, is crucial for the Illinois Waterway. The Dresden Island Lock and Dam serves as a vital route connecting Lake Michigan to the Mississippi River and beyond. It’s like a highway for farmers and vendors to transport their goods across the United States, reducing the number of trucks on the roads and enhancing the overall efficiency of the transportation network. For the first time since it was built, the Dresden Island Lock and Dam was drained for the restoration project to begin.

Scope of the Project

As part of the ongoing Illinois River Basin Lock Rehabilitation project led by the United States Army Corps of Engineers, Alberici Constructors contracted Schnabel in July of 2023 to install permanent concrete anchor rods for structural support of the new miter gates on the east side of the Dresden Island Lock. Schnabel’s main task was the installation of 32 anchors (16 anchors on each side of the lock) for a total of 450 LF drilled, with strict verticality tolerances, and 480 LF of anchors installed.

Absence of Fill Materials and As-Built Drawings

The Dresden Island Lock and Dam, being nearly a century old, presented several challenges due to the unknown nature of its construction materials and the absence of any fill material and as-built drawings. This uncertainty made it hard to predict whether we would encounter rebar steel when drilling into the concrete. To overcome this, Schnabel adopted a method of hand core drilling for the initial 3 feet of the holes, switching to our drilling machine for the remainder. The confined drilling area required the use of a Klemm 702 drill with a 5.5-inch down-the-hole hammer. Sometimes, accessing our designated drilling locations proved cumbersome due to a 4.5-foot-tall concrete block obstructing the way.

Other Challenges

Furthermore, we had strict tolerance requirements for installing the anchor bars, as Alberici needed to place a plate on top of them, making anchor testing challenging. If the plate didn’t fit, Schnabel would be held responsible, necessitating anchor removal, hole grouting, and a fresh installation. Adding to the complexity, certain access points could only be reached via the use of cranes on-site. These crane moves required timely notices and pre-planning as multiple contractors were vying for the same resource.


In August 2023, Schnabel achieved the successful installation of 32 anchors, supporting the construction of new miter gates on the east side of the Dresden Island Lock and Dam structure. Despite encountering numerous operational challenges, the project was executed safely, within the budget, and to the satisfaction of our client. We extend our gratitude to all those who played a role in making this project a success.

Permanent Concrete Anchor Rods

The completely drained Dresden Island Lock

Permanent Concrete Anchor Rods

Schnabel team member operating the grout plant and silo for the grouting of the anchor rods

Permanent Concrete Anchor Rods

Klemm 702 drill rig being flown over the Dresden Island Lock to complete work on the opposite side’s miter gate

Permanent Concrete Anchor Rods

Schnabel’s concrete anchors with the new miter gate installed