Banner - An Overview of Seawall Repair Methods

Ken Braunlich: An Overview of Seawall Repair Methods

Body - An Overview of Seawall Repair MethodsThis article is an excerpt from Episode 15 of Alchemy-Spetec’s podcast The Injection Connection, featuring an interview with Seawall Repair Network®’s Ken Braunlich. The Injection Connection is hosted by Charlie Lerman. (If you’d rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Ken Braunlich: Seawalls are very dynamic structures. They’re constantly affected by enormous pressures, whether it’s on the waterward side of the structure involving the canal, the river, the lake, the ocean – but then you also have to contend with the landward side as well, the pressures that build up from heavy rain, wave overlap over the seawall, irrigation and the land mass itself. There are a whole lot of concepts developed by engineers, specifically the Army Corps of Engineers, going back to the 20s and 30s when they started to create the engineering for these structures. They developed mechanisms like the Deadman anchor systems and modifications to the structure itself – like whether it’s installed on a footing or a driven system or whatever the case may be. They’re very complex.

So for decades, the problems have begun when a seawall is affected by soil instability, soil migration, and soil sharing that leads to the damage of other infrastructure.  And quite simply, over a very long period of time, it really has boiled down to dumping cementitious materials behind seawalls, very heavy materials, and even more lightweight cementitious materials like microfills. Of course, that didn’t work. Essentially the concept there is tantamount to trying to fill a mixing bowl with a straw. It just doesn’t work.

And so because of that over time contractors and engineers tried two-part foam. Of course, two-part foam, really the more realistic applications associated with that in the original concept of design is for heavy slab lifting of concrete horizontal structures. We can lift concrete highway slabs and other heavy structures with this very aggressive high-viscosity material. We have some of the most superior two-part foams here at (Seawall Repair Network® parent company) Alchemy-Spetec: AP Lift 430, AP Lift 475 so forth. They’re used by Departments of Transportation across the United States. But when you put that behind a seawall, with the high-viscosity material and the super compression of soil, you’re actually displacing soil and causing fracturing. When you inject that kind of material behind a seawall, you’re actually putting a lot of lateral load on it. That has unfortunately led to the premature destruction of a lot of seawall structures.

What we found out with our single-component material at Alchemy-Spetec was a superior performance with 40 to 50 times unit size in terms of the capacity to void fill, but also spread without pushing against the landward side of the structure, and the toe of the structure itself. We discovered through research and development that we could create this very specific grout pattern that’s articulated behind the wall on the landward side and use the thinner span between the injection points to create these dewatering channels, which allows us to do something that’s never been done before. We can systematically control and optimize the release of hydrostatic pressure from the landward side to the waterward side but also allow in high tide conditions or high storm conditions on the waterward side when the water level is high. We can control the hydrostatic pressure on the landward side.

What that does is it keeps all the pressures balanced, and by keeping the pressures balanced on both sides of the structure we achieve stability. It’s all one big system. It starts with the injection pattern, and the use of the very high-quality repair material SW-RP1, manufactured by Alchemy-Spetec. And of course the art of the installation of that material.

View the video version of this excerpt…

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