Concrete Piers in a Coastal Flood Zone! 

A RU-vidr, Tyler Ley, talked about epoxy coated rebar in a video a couple years ago, and the issues surrounding it. Just thought I'd mention it, if anyone was curious. I guess galvanized rebar was only around 10% more in cost, which I can't imagine was a deterrent in this job. I'd be interested in hearing the reason why it wasn't used on this project as well.

as a GC i had the same exact thought.

@@Fetecheney The choice to weld rebar to the steel i-beam. Welding galvanised steel poses some health risk due to vaporisation of Zn. That vaporisation would also leave 4-6” of the rebar unprotected from corrosion. Same is also true however of epoxy rebar. It appears they are using standard carbon steel rebar for those hold-down connections for this reason. This can effectively be done by upsizing the holdown steel, essentially engineering for 35-40% degradation due to corrosion over 50 year service life. My guess is much of these material choices are driven by budget and possibly availability. The best way to do this job would have been FRP rebar throughout then installing 304SS holdown rods for welding to steel beams. I’d also be concerned with direct wood connections used on green concrete. Even w/good pour and proper vibration, concrete will shrink over first 6 month cure. It will do so non-uniformly. Given spacing of piers, I could see this floor level exceeding 1/8” in 10’. If they can’t allow a 6 month cure before decking, I’d recommend floor level survey be performed after completion of building envelope, which should be at or after 6- month cure. If floor levels exceeds limits, floating leveling material prior to finish flooring is highly recommended.

@@MichaelM-to4sg Bro, thanks for taking the time to enlighten me. Time to go into a rabbit hole on Fiberglass reinforced polymer rebar... I remember in the video he was saying it was supposed to be 'hundreds of years' house. I guess the 50-year service life would out the kibosh on that? Another question if you could, would the chloride penetration be accelerated because it's close to the ocean? What are the factors that cause chloride to get into the concrete?

@@Fetecheney Yes. Many factors; temperature, humidity, wind, flood/splash cycles, etc. I’ve never built on Atlantic but I know salinity in air is much greater there than coastal regions I’m more familiar such as Bandon Dunes, Or, Fox Island, WA, Mendocino, CA and Carmel, CA. We typically calculate based on published tables but I’ve had to hire labs to provide study data on some occasions.

part of the reason is that the fibers are pointed in every direction.

@@akacreq just wait till there is a water situation.... Rebuild Time... I just don't get it, why you would go so low quality, especially when you are that close to water.... that can damage the OSB in a hurry. Just lay a 2x12 and OSB outside for a month... the 2x12 is fine, the OSB will have been compromised.

@@jameschupp2230 depends on the used glue. But I guess in the construction Industry they do not have marine grade plywood?

The water will never get that high.....