Luckett and Farley Structural has been working tirelessly with one of our clients to address certain corrosion issues they’ve been having at their facility. We all know that concrete cracks; well, carbon steel rusts. But the processes within their 2002 industrial building exposes the structure to the double whammy of extreme heat and steam, occurring in hot-cold cycles throughout the year. This chloride-filled environment has done a number on the wide flange beams and girders above this process area and to the reinforcing steel within adjacent 24″ thick concrete walls.
In situations like these, the objective is to restore the structural components to their “pre-rusted” condition (strength and stiffness), as reasonably and feasibly possible. Even more importantly, when you’re playing with your client’s money, the focus should be on educating and advising them of their options: there is ALWAYS more than one way to address a problem and they all have financial implications.
Here is our procedure/methodology for repairing corroded structural steel:
- Step 1: If there is an imminent hazard as a result of the corrosion, provide temporary shoring.
- Step 2: Prepare a testing program to evaluate the impact on the quality of the material or extent of corrosion; document the damage.
- Step 3: Provide viable repair schemes for a Contractor to estimate and the Owner to review; obtain feedback on feasibility and cost.
- Step 4: Perform the repairs. Give due consideration to the fact that the existing members may already be loaded/stressed prior to repairing. Any new material added to the corroded member may not be as effective if the (gravity) load isn’t removed first!
- There are numerous methods to repairing structural steel: most are project-specific and can involve supplemental plating, reinforcement, etc. What’s most crucial is Step 5: Either eliminate the corrosive environment or protect against it.
Since eliminating the harsh environment is obvious (if you have the luxury to do so), here’s just a couple protection solutions we’ve employed that you may consider for your own corrosion ailments:
REBAR:
-Cathodic Protection with Galvanic Anodes: Attach zinc anodes to the reinforcing mat in a grid-like pattern to force the corrosion to occur within the less-noble metal…zinc. These galvanic anodes do deteriorate so care and caution into providing the proper quantity should be given.
-Corrosion Inhibitor: Since concrete is porous, this type of product can be spray-applied to coat the surface of the existing concrete.
STRUCTURAL STEEL:
-Epoxy Coating: If heat is not a factor, this could be a viable option in which the carbon steel is coated with a barrier to protect against chloride attack.
-Cathodic Protection with Inorganic Coating: Not many companies manufacture this type of solution, but it’s ideal for our case in point, wherein an inorganic ceramic (zinc) coating is applied to the structural steel and an AC current is connected. This forces the corrosion to occur within the zinc coating, slowing the rate of corrosion on the protected substrate by as much as 1/25 of the pre-coated condition. This technology appears to have proved successful for many years and perfected by one company in particular, Applied Semiconductor. The benefit here: it can withstand temperatures of up to 800 degrees Fahrenheit!
In situ, galvanizing, like painting, is typically not as effective as the aforementioned options in that it’s spray-applied since it relies on proper bond with the substrate and is more susceptible to scraping/flaking off with time and exposure.
Like a tooth cavity, the longer you wait to address corrosion of your steel building, the more money you will spend when you eventually decide to take action. Take steps sooner rather than later (or when it’s too late) to correct the issue, as it won’t fix itself. At least, that’s what my dentist says, anyway.
About The Author
Related Posts
Angel’s Envy: Story of a Design Concept
Passion, excitement (and a little bourbon) inspire a unique design process
Representatives from Louisville Distlling Company asked Luckett & Farley to submit a concept and proposal for a new microdistillery in downtown Louisville, Kentucky. The facility was intended to be the new home to a rising star in the world of bourbon, called Angel’s Envy. The brand’s story to stardom is as good as the product itself. To manifest the story into [more...]
Small Projects, Big Relationships
In the words of the Greek orator, Demosthenus, “Small opportunities are often the beginning of great enterprises.” Great concept, but how do we implement his sage advice? While searching for some answers, I decided to look at our company’s Core Values. Do our Core Values apply to each & every project – even the small [more...]
North American auto companies focus on their people
Employee passion is contagious and the results speak for themselves.
American car companies and A/E firms have one thing in common. People. Sure, there are probably a few other things they have in common. They both build and design objects that shape our lives, but I would argue that it’s the value they place on their employees that brings them together. I recently visited the [more...]
Creative problem-solving saved big dollars for sawmill project
L&F architects, engineers knows their stuff and backed by research
Luckett & Farley recently had the privilege to design a sawmill facility for one of our long-standing clients. During its design, we faced a challenge from the state fire marshal’s office (the authority having jurisdiction) regarding the building occupancy classification. The fire marshal had seen some horrible conditions in other sawmills and was strongly leaning [more...]
Data Centers are Energy Hogs
Here's a no-brainer data center cooling solution
Data Centers are energy hogs. A recent project had computer racks which consumed 35 kw for each rack. When the computer consumes 35 kw of energy, all of it becomes heat (think about it, nothing goes back out on the wires). That’s 10 tons of cooling for a rack about the size of your desk. [more...]
How to Defuse a Volatile Situation
Advice for all designers
Sometimes in a project meeting an architect finds himself on the receiving end of criticism, whether he/she legitimately deserves it or not. It’s just part of the job. Now, how he/she chooses to respond to it reveals the character and integrity of the architect – which ultimately may determine how long he’s in business. So [more...]
The Hands Off Approach to Grooming New Leaders
As President and CEO of Luckett & Farley, one of the biggest challenges I face is finding the sweet spot when it comes to mentoring our future leaders. It’s a fine line between being too distant and being just ”hands off” enough to allow our rising stars to gain valuable experience in dealing with the myriad of [more...]
Correcting Mistakes, the Luckett & Farley Way
When something doesn't go as planned, how you handle it can define your entire practice.
Mistakes are a part of business. Any architectural, engineering or interior design firm that hasn’t suffered from a costly mistake probably doesn’t have any employees! Sure, we’ve all been in that situation – myself included. Unfortunately, the most effective way to have a lesson permanently seared into your brain is to make a big hairy mistake and have the initiative to shoot your [more...]
Pingback: ‘Sensing skin’ could detect cracks in concrete structures | Innovation Toronto