Scaling up monitoring for major maintenance demand

Cathodic protection of structures in steel and concrete has been on the rise in the Netherlands in recent decades. Not surprising because this method of protection is simple and inexpensive and can save the owners of buildings, works of art and steel structures a lot of money. Now that we are facing a huge maintenance problem in this country from the many aging buildings and infrastructure works, the question is how to tackle it. According to expert in cathodic protection (RD) Anthony van den Hondel, it is precisely RD as a technology that can play an important role, especially if we are smart about all the available data.

Currently, many hundreds of structures in the Netherlands are equipped with KB. Relatively few if you consider that the system was invented almost two hundred years ago in the United Kingdom to protect the ship's hull. It wasn't until the 1980s that the technique was actually used in the Netherlands. Partly due to the introduction of a European standard in 2000, things went fast after that. Van den Hondel has been active as a corrosion engineer for thirty years. He currently owns consulting firm Cathodic Protection-Advice (CPA) and Cathodic Protection-Supplies (CPS), which supplies products and accessories. "You could say my hobby is corrosion, and you fight that with cathodic protection. It's on ships, gas pipelines, bridges, sheet piling, tanks in the ground, drilling rigs, and in recent decades, increasingly in concrete structures. In the Netherlands we have made a lot of progress in the last 30 years, which puts us on a par with the United States and the United Kingdom as far as this technique is concerned."

Concrete maintenance is becoming increasingly important, especially with the large number of structures built in the 1950s, 1960s and 1970s that are nearing the end of their technical lifespan. (See article Concrete Maintenance Platform elsewhere in this issue.) Van den Hondel: "We are facing a huge maintenance challenge. Eighty to ninety percent of all concrete maintenance problems are caused by rusting of the steel reinforcement. This is extremely difficult to tackle in a sustainable way, but with KB it works. With it you can very well perform condition-dependent maintenance, i.e. intervene when necessary. Concrete lends itself well to this because you can measure the corrosion status with tools and plan maintenance accordingly. Rijkswaterstaat has now equipped more than 50 structures with KB but when you realize that it manages many thousands of structures, you know that there is still work to be done."

A recent development concerns the extensive automation of monitoring KB systems. New challenges and opportunities arise from the multitude of data becoming available. "KB is an active system: when it is on, corrosion stops," Van den Hondel continues. "So it needs to be monitored, and modern techniques can do that. An autonomously functioning KB system transmits data about condition, load and exposure, such as temperature and humidity, to a central monitoring unit via a data connection. The sensors are of high quality and we have thirty years of experience with them. So we also have thirty years of data that we generate, process and analyze. This in turn allows us to control the maintenance of other structures with very sophisticated software. So we are getting better and better at managing our infrastructure."

As an example, Van den Hondel cites one of his customers, who has seventeen KB systems in use. "At the same production site, KB systems on concrete were realized by thirteen different contractors, each with its own way of working and its own monitoring system, with its own software and its own login data. To make that manageable, a dashboard was created that brings everything together in one overview and can be managed and controlled from there. In the event of a problem, this then gives a signal at the highest level that you can then zoom in on. Concrete develops damage slowly, so you don't have to intervene acutely, but can plan and take targeted action. Discussions are underway with RWS and others about how we can develop platforms based on expert systems, with which we can do automatic processing of RD monitoring on a large scale. The labor market is thin, so we have to man the maintenance tasks with fewer and fewer people. That can be done with KB and expert systems for monitoring. The service level agreements of contractors usually state that they respond within a certain period of time. That also works with KB, so for that you just have to set up and manage the system. To achieve this, we have everything in place." And in conclusion, "There is inevitably a scaling up of the market coming. We are going to maintain more, repair more, apply more KB and monitor more. Scaling up is currently limited by the number of people the market has available, but it's a waste to put scarce people on data processing and interpretation. Tackle it smartly, and it will succeed."