Post Tension Cable Fails
Post Tension Cable Fails
Post tension cables are the invisible force that holds many concrete structures upright. The high-strength steel strands, which resemble metallic ropes poised for an act of architectural acrobatics, are the structural foundation of concrete slabs that make up much of a city’s downtown core. They allow slabs to be thinner and less bulky, freeing designers with more creative opportunities to erect elegant buildings that can stand the test of time and weather.
However, while post-tension cables have allowed for more innovative designs and opened up a whole new realm of possibilities for condo builders, they are not without their risks. If improperly designed, installed, or maintained, they can pose significant safety risks and even result in structural collapses. The good news is that, with foresight in construction and diligent inspection, these structural elements can hold up to the demands of both man and nature.
A recent case of post-tension cable failure in a Calgary condominium highlighted how important it is to understand the role these structural components play before entering into ownership of a building constructed with this method. A structural collapse due to a post-tension cable fault can be catastrophic, costing owners and occupants significant monetary costs as well as forcing them to temporarily relocate while repairs are made.
When a post-tension cable fails, it can cause a large and unstable crack in the structure that exposes the high-strength steel to water, oxygen, and chemicals that can accelerate corrosion. This is a major concern as the corrosion of steel can lead to a catastrophic structural collapse, potentially resulting in a loss of life.
While the risk of a post tension cable failing is rare, this is still an extremely serious problem to deal with in any property. The first step is to identify the issue, which is possible with non-invasive tools such as Ground Penetrating Radar (GPR). Once the damaged section of the slab has been identified, specialists can detension the tendons, splice back the broken cable, re-stress the cable, then patch with high-strength grout.
This process is a highly-specialized procedure that requires specialized equipment and a great deal of knowledge to perform correctly. For this reason, it is not recommended that DIYers attempt to replace or repair these structures themselves. However, if you are a condominium owner in Calgary with post-tension tendons, it is essential that you schedule regular inspections of the structural integrity of your building to identify any signs of wear and tear or deterioration.
With foresight in design, rigorous inspection, and careful maintenance, post tension foundations can continue to withstand the pressures of heavy loads, seismic activity, and our expansive clay soil that swells and shrinks with changes in moisture. Regular inspections can detect any damage or deterioration and help you prevent future issues, saving you money and ensuring your home’s safety for years to come.