Safely Cutting a Post Tension Concrete Slab

What Are Post-Tensioned Slabs & Why Are They Used?

Post tension concrete slabs (sometimes called PT concrete or PT slabs) are constructed with strength and durability in mind. PT concrete is the concrete of choice on many construction projects, since it has many advantages over traditional concrete slabs containing rebar.

What Are Post Tension Concrete Slabs?

PT concrete is a concrete slab that is reinforced using a special “tendons” that are made from steel wire. These tendons are inserted in ducts that are then covered by the concrete. Once the concrete hardens, the tendons are tightened, or “tensioned”, and locked into place, creating a permanent compression to the concrete that makes it extremely durable and strong. 

Concrete containing post tension cables is great for projects that require large slabs, such as commercial buildings, parking garages, bridges, and even homes. The concrete can be thinner and not require as many supporting columns, but still have the needed strength. It can save money during the construction process, without compromising quality. PT concrete tends to have less cracking than concrete containing rebar, and also performs better on soft soil.

Safely Cutting Into Post Tension Concrete Slabs

An issue with post tension concrete slabs can arise if the concrete ever needs to be disturbed, for any reason. When a concrete structure needs to be remodeled, it can often require drilling or cutting into the concrete. When this is necessary, the post tension cables must be avoided at all costs! If a cable is hit, it can cause it to snap and compromise the strength of the slab. In the worst case scenario, the snapped cable could hit someone nearby and cause substantial injury, or even death!

Before disturbing post tension concrete slabs, it is important to locate all embedded cables. To do so, ground penetrating radar (or GPR) is typically the technology of choice. Dedicated GPR concrete scanning experts can be brought in to scan the concrete in the area to be drilled and mark the concrete up for safe drilling. They may also provide a CAD overlay of the concrete that indicates the locations of all of the post tension cables. 

Safe Post Tension Concrete Drilling: A Success Story

Enhanced Scanning, a GPR scanning company in Southern California, knows a lot about scanning concrete slabs—including PT concrete slabs. They recently had a project that required extensive coring into existing concrete—in 130 locations, to be exact!

The team at Enhanced Scanning carefully scanned the PT slab and indicated where it would be safe for their client to core in order to avoid post tension cables. As a result of their accurate scanning, no post tension cables were hit, or even nicked! It was a 100% successful project! This wouldn’t have been possible without GPR scanning by a skilled technician like those at Enhanced Scanning. 

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