Flood Risk Management and Bank Stabilization Project Selma, AL

The U.S. Army Corps of Engineers, Mobile District, will conduct an industry day to discuss the proposed design of the flood risk management and bank stabilization project near downtown Selma, Alabama. The project is anticipated to consist of bank stabilization with approximately 1,000 linear feet of soldier-pile wall along the Alabama River.

Mobile District is seeking maximum input on the means and methods of construction of the soldier pile wall while minimizing impacts on the historic structures along the bankline of the Alabama River. The soldier pile wall will be constructed to a top elevation of 100 ft NAVD88, and a secondary retaining wall will be constructed to a top elevation of 110 ft. Rip-rap protection will be placed at the toe of the wall to a top elevation of 90 ft.

It is anticipated that soldier piles will be placed vertically into pre-drilled holes and grouted into place. Reinforced precast concrete lagging panels will be installed between each soldier pile, creating a retaining wall structure. Tie-back anchors will be installed to provide lateral support. The NAICS Code for this project will be 237990 Other Heavy and Civil Engineering Construction. The project is anticipated to be advertised as a Design-Build procurement.

Contract advertisement is anticipated for Spring 2026 with an estimated magnitude of $25 - $100M.

A general description of the project can be found in the Selma, Alabama Flood Risk Management Study Integrated Feasibility Report and Environmental Assessment located at the following link: https://www.sam.usace.army.mil/Missions/Program-and-Project-Management/Civil-Projects/Selma-Alabama-Flood-Risk-Management-Feasibility-Study/Primary-Documents/ The draft soldier pile wall design, along with recent Structural Assessment Reports of each property in the project area, will also be posted at the following link the week of March 24, 2025: https://www.sam.usace.army.mil/Missions/Program-and-Project-Management/Civil-Projects/Selma-Alabama-Flood-Risk-Management-Feasibility-Study/Design Phase/ The event is scheduled from 9:00 a.m. to 3:00 p.m. CDT on Tuesday, April 22, 2025, at the Mobile District Annex Building, 201 Saint Michael St, Mobile, AL 36602. The event will include a general session with a presentation on the project overview, status, and schedule, followed by an open discussion/feedback period.

At the contractor's request, individual 30-minute break-out sessions will be held from 9:00 a.m. to 12:00 p.m. on Wednesday, April 23, 2025. Contractor comments and suggestions are strongly encouraged. Please e-mail Mr. Jonas White at jonas.white@usace.army.mil by 5:00 PM CDT on April 18 2025, if you plan to attend this event. Provide your name, contact information, the company you represent, the number of people in your party who will attend, and whether you want to participate in the individual breakout sessions.

Questions to Consider Please be prepared to discuss the questions and statements below. These questions and statements may be revised prior to the event, if necessary, but the intent is for them to be used to guide the discussions. What are the best pile installation methods available to reduce ground vibrations to the existing historic structures? How would you define the vibration limits for this project and how would you outline a vibration monitoring program?

Will the installation of the tieback anchors produce vibrations that would threaten the stability of the existing buildings. The “tie-backs”/anchors being considered for this project are prestressed ground anchors (cement grouted, prestressed tendons (bar or strand) installed in soil), per recommendations of the Post-Tensioning Institute (PTI), limiting the anchor capacity to the available soil-grout bond values. Are there other types of tie-back/anchor systems that you think should be considered?

Note that the conditions are not practical for “deadman” anchoring. Testing of tieback bond is planned by drilling and grouting a tieback vertically and performing a tension anchor load test at several locations where access is available. Is testing in a vertical orientation acceptable? It is assumed that due to the restricted access, most of the work will be performed from the water. What access is required from the landside?

Are there other types of walls or bank stabilization methods that may be better suited to the site conditions? What would be the best possible access and staging locations along the riverfront and if existing City-owned land is sufficient for landward vs. riverward construction purposes? Depending on the width of real estate created between the buildings and the river, are there different construction methods that may be used to decrease potential impacts to the historic structures?