huangyhg

aci vs pci
i'm reviewing a set of precast concrete submittals. the precast engineer has taken it upon himself to redesign the cast-in-place embedments that the precast will attach to.
he's designing them using pci 6th edition (chapter 6), and is coming up with drastically different results than what we had designed using aci.
the contractor has offered a credit to the owner, and now the owner is hot to change. problem is, i am under the impression that pci is precast only and aci governs cast-in-place (although i can't find anything in either code that limits the scope of the code.
we're reviewing his calcs against pci now, because we can't believe the difference, but if he did everything correctly, i need to ensure that pci is acceptable for cast-in-place design.
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if you are under the ibc code, it should spelled out which code to follow in chapter 19 and there are references in chapter 35.
yes be careful with this one. precast concrete has better compaction, quality control and tolerances, than in-situ concrete. i imagine this difference may be reflected by way of less conservative procedures for the precast.
see section 6.5 of the pci design handbook and page 10-36. pci says they have performed tests that substantiate their connection method as a code-approved alternative. but it is ultimately up to the engineer-of-record and building official to approve it.
the pci handbook 6th edition uses the procedure from aci 318-02. the values you get should be close to the same. pci justs presents the information differently. pci breaks everything down so that you connection fails into one specific case. aci is the general stuff everything is checked and the numbers will show what condition controls. pci also makes some assumptions about the failure planes. aci-318-05 makes everything much clearer than 02. 02 is a little hard to follow. just check it using either book and the answers should be pretty close
that's just it, they answers weren't remotely close -- the pci version came up with dramatically smaller embed requirements. ends up that the submitted calculations had an error in them -- once corrected, pci and aci were pretty close.
thanks for all the feedback, i really appreciate it.

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