PCCP condition assessment services from PICA Corp.
Large-diameter prestressed concrete cylinder pipes (PCCP) are the most common means of transporting raw water, potable water and waste water over long distances in large volumes. Across North America, in particular, these types of pipelines make up critical infrastructure for municipalities and industrial companies alike. Despite being a highly robust and durable pipe type, PCCP lines still require routine condition assessments to ensure they are free from wire breaks and corrosion damage.
At PICA, our team of highly experienced technicians is here to help you with your PCCP pipe condition assessment needs. Next, we will review some of the most common factors that lead to PCCP pipe failures and how PICA can help you prevent pipeline failures through our condition assessment services. Keep reading to find out more about prestressed concrete cylinder pipeline failures.
Key Sources of Damage:
Many municipalities and pipeline owners blame broken pre-stressing wires as the primary cause of PCCP line failures. While broken wires can certainly cause PCCP failures, several other degradation mechanisms can lead to PCCP failure. These factors typically fall into four main categories:
Most PCCP pipes are buried underground. This ultimately can cause failures due to the soil carrying chemical elements like chlorides, sulfites, and sulfates, which are corrosive to the metal parts of PCCP pipes if the mortar coating cracks and allows the ground water to contact the prestress wires and eventually the steel cylinder. At PICA, our technicians and tool-chest of pipeline and water main inspection tools can detect cylinder corrosion, wire corrosion and hydrogen embrittlement of your prestressed concrete cylinder pipes. If PICA inspects your PCCP pipelines, you will have a clear picture of the actual condition of the pipeline and can make informed decisions regarding repair, rehabilitation, or replacement. In theory, most pipelines can last well beyond their design life (“life extension”) so long as the inspection frequency is sufficient to find the problem areas and the pipe owner takes action to locally repair or replace distressed pipe.
Loss of pre-load
When pre-stress wires crack and break, they can release the compressive force on the thin steel cylinder. Usually, it takes more than 20 adjacent wires to fail in one clock location before the loss of preload is significant enough to rupture the cylinder. This kind of wire failure is easy to detect and technology has been around for over 20 years to detect and quantify this degradation mechanism. However, wires can also break from hydrogen embrittlement, in which case the breaks may be scattered at various clock positions, and may therefore NOT release any pre-load on the cylinder. It is well known that local loss of preload is often fully back to normal preload within 6″ to 12″ of the broken wire location; however, if the cement condition is good, and the cement is well adhered to the wires it can assume the preload that the wire was carrying, and there is no effect on the cylinder.
PICA has technology that can not only tell the difference between corroded-through prestress wires and those cracked through by embrittlement, but we can also detect whether there is any loss of preload, AND if the cylinder is also corroded.
Poor Quality Construction
PCCP water mains are unique in their construction. If your PCCP pipe was constructed with poor-quality wires or concrete, then they will be more susceptible to groundwater corrosion. Furthermore, poorly constructed PCCP water mains may also contain welding defects in the spiral weld of the cylinder or the butt welds, inadequate pipe anchors and restraints, undetected mortar damage, and poor bedding preparation leading to uneven support of the pipes, bridging and point-source loading.
Wear and Tear
While PCCP water mains are strong and durable, even they will eventually succumb to the effects of aging. If your PCCP pipe is exposed to pressure surges or ground movement, they will be more susceptible to premature degradation. Freeze and thaw cycles of clay soils can cause significant soil movement, possibly resulting in your PCCP water mains pulling apart at the joints. These natural factors, combined with the effects of hydrogen sulfide concentrates in pipes carrying wastewater, will cause your PCCP lines to corrode from the inside and eventually fail over time.
PCCP Condition Assessment Services from PICA Corp.
Since most PCCP mains are large diameter, unexpected pipeline failure can result in catastrophic damage to the alignment and the surrounding community. With the threat of potential fines and extensive cleanup costs, preventing PCCP line failures through routine condition assessments is not only cost-effective but also critical for avoiding such losses.
At PICA Corp, we use a range of innovative non-destructive technology to quickly and efficiently assess the condition of your PCCP mains. Our water main condition assessment ensures you have all the necessary data to make informed decisions regarding your pipelines’ health, repair, rehabilitation and replacement. So when you need to be sure that your prestressed concrete cylinder pipes are in safe working condition, trust PICA to have the innovative water main condition assessment tools and services you require!
Contact PICA today to learn more about how our team can provide you with a comprehensive condition assessment of your water mains, wastewater, raw water, slurry pipelines and more!