Connecticut Waterfront Structures

GNCB Consulting Engineers, P.C. in Old Saybrook, CT has helped to reconstruct the faltering retaining walls that comprise the Connecticut waterfront. Our dedicated team of professional geotechnical and structural engineers have many years of experience in this rebuilding effort. With over 50 years of engineering experience, including historic preservation work, GNCB is able to solve the many problems that plague our waterfront.

Regardless of the rebuilding effort needed, the first step is to secure the necessary design and building permits from both the Connecticut Department of Environmental and Energy Protection (CTDEEP) and the Army Corps of Engineers (ACE). For the most part a permit is needed prior to starting any construction and/or repair work; there is, however, an expedited procedure to complete emergency repairs ahead of securing a permit. 

The initial part of the permit and design process involves a test boring program to determine subsurface conditions. These conditions likely consist of some surface man-placed fill and organic soils underlain by overburden sand and or glacial till. In some instances, the surface overburden soils may be directly underlain by bedrock.  Borings may be drilled from land or from the water, the latter requires special barge equipment.

Retaining walls typically consist of steel sheet piling, reinforced concrete, or gravity stone walls. Selection of a suitable wall type often depends on the specific geometry of the wall/waterfront, the depth of free water on the outboard side of the wall, and the depth to suitable bearing soil. The reinforced concrete wall and stone walls have some overall height limitations, something in the range of 20 ft. or less. While steel sheet pile walls can serve higher depths, a system of tiebacks or anchor system is needed to keep the wall laterally stabilized. Steel sheet pile walls can be made very stiff with the integration with heavy steel H piles; this stiff pile permits greater wall heights without the need for lateral anchor support. Regardless of the wall type used, particularly for reinforced concrete and stone gravity walls, some degree of erosion protection is needed for those walls in a high hazard zone, per FEMA regulations and mapping. 

Engineers at GNCB can help in your permitting and design to rebuilding a waterfront retaining wall on your property with an assurance that it will survive the harsh storm events that can endanger our area. For comprehensive services that offer value and integrity from a team you can trust, GNCB Consulting Engineers, P.C. provides a unique blend of structural, geotechnical, and historic preservation needs.