Gene,
Without seeing the plans and doing some investigation, the answer to your question is not worth much. Besides siesmic, the engineer is also balancing wind load, snow load, design, and soil type.
I build in the Pacific Northwest. We are in the highest siesmic catergory and build on some of the worst soils. Then add to that depending on where you build we hit some of the highest wind loads. I have seen an array of different amounts of rebar from an array of engineers. Engineering is like going to the doctor, they are only practicing.
One trap many people fall into is going with the low bidder. Many times it is the only thing people pay attention to and they don't actually interview their engineers. Needless to say most people including many builders are not educated enough on the subject to even know what questions to ask.
Your typical engineer who does residential work may or may not be your best fit for a concrete structure. Preferable you would go with someone who has a lot of concrete experience such as tiltup, precast and the like. I also understand you could be geographically constrained by the number of engineers in your area to choose from.
That being said it does not look too out of line for the amount of rebar he is using. Things that you can discuss with your engineer to try an reduce your rebar tonnage is PSI of the concrete mix you will use, grade of rebar is it grade 40 or grade 60, ACI 318 and the ratio of rebar to concrete that is set in the code. Is your wall 11'6" above gade or is some of it filled against. Is your engineer using the IBC or IRC, in the IBC the engineer is not constrained by the restrictive tables in the IRC. The list could go on and on. So it is always best to consult with an experienced ICF or concrete professional before you start your project, you may pay them some money, but you will be money, time,and heartache ahead.
ICF Contractor |