Post-Tensioned Slab-on-Grade: The Solution for Soil Stability Challenges

Soil stability must be a consideration in the design and construction of any type of structure, irrespective of the region or surface appearance. Historically, use of rebar has been the typical method of reinforcing a concrete slab to provide the strength and durability needed to maintain structural integrity. However, standard reinforcement techniques may not be sufficient to prevent slab damage or degradation under many conditions.

Tendon LLC developed its slab-on-grade technology as a superior means of meeting the challenges presented by a wide range of soil conditions. These ‘problem soils’ include shrink-swell clays, often called ‘fat’ clays.  These soils predominant in the southern regions from the Mississippi River to the west coast.  Along the suncoast from Louisiana, Mississippi, Alabama, Georgia and Florida these shrink-swell clays are found in localized pockets.  Most notable of these are the Yazoo clays, Gainesville and Ocala and Montgomery.

Other unstable soil foundation conditions include karst. In the United States, 20 percent of the land surface is karst which has characteristics of ground subsidence, sinkhole collapse, groundwater contamination, and unpredictable water supply.  The area most prone to sinkhole collapse is the central Florida area in Ocala, Orlando, Lakeland, and Tampa areas.

Our in-house engineering and project management teams assure that the structural slab on ground design is specific to each project and enables us to provide quick turn-around at every stage of a project, from initial concept to completion.

Compared to conventional slab reinforcement configurations, post-tensioned slab-on-grade construction reduces costs, provides greater durability, and can be used regardless of soil characteristics.

Post-tensioned slab-on-ground provides economic advantages because it decreases the amount of concrete and rebar required to provide the required level of structural integrity. Labor costs are also reduced because less material is used in slab construction and construction times are optimized.  That’s why builders post-tension with increasing frequency in lieu of conventional rebar slabs.

The advantage of post-tensioning is the internal compressive force it imparts on the concrete. This increases resistance to deflections and cracking caused by a variety of soil problems such as lift, shrinkage or swelling due to temperature or moisture changes. (For more specifics about post-tensioning, click here.

Slab-on-grade construction has a wide variety of applications including industrial and commercial floors, tennis courts and recreational surfaces. However, it’s most common use is for single-family homes and multi-story apartment buildings. As with other Tendon System products and services, slab-on-grade construction is a problem-solver. It delivers unsurpassed strength and long-term durability and often makes it possible to complete a project that would not be viable using other slab construction techniques.