huangyhg

pre-fabricated precast bank vaults
a new bank facialty will contain a pre-fabricated precast vault 18 ft x 75 ft, with a precast concrete lid.
the supplier of the vault says they don't engineer them and they cannot provide a review letter from a structural engineer. they use the same panels and just rearrange them to fit their customers size requirements. they can only provide panel weights. their drawings don't show how the panels are connected to the floor or to the adjacent panels.
questions - (code ibc 2006)
1.does a free standing precast concrete structure inside of another structure require design by licensed professional/structural engineer? (for seismic loads at minimum)
2.does the vault need to be inspected per ch 17 special inpsections? do the provisions of "approved fabricator" apply?
thanks - i look forward to hearing other's experience on this. i think both design and inspection per code apply. the architect does not want to contact the code official - because if we ask he thinks the offical will require both of the above.
lrhg

i might look for a new supplier
1) yes
2) no
that vault is larger than some buildings i have designed. if you are the eor, did you have any precast specs you can reference for any language to make them show design calculations? specs have saved me before more than one time in this way. i will refrain from saying anything negative about the architect.

seems to me that there are security questions here for the bank. why the secrecy in the construction of the vault?
i helped design a penitentiary and numerous bank vaults in the past, and both had very specific structural requirements by the clients (state and bank) for the whole of each structure.
security is a structural issue here. you need to put your concerns in writing to your client. i would.
mike mccann
mmc engineering
thanks all for sharing your experience and thoughts on this.
i understand bank vaults need to conform to an astm standand that addresses a ul fire rating and vault classification that relates to insurance. the astm standard refers to aci 318 for concrete design.
i don't think the manufacture is necessarily keeping the vault construction a "secret" - the shop drawings look rather straight forward, though no info on reinforcement or connections. i think the vault supplier needs to take design responsiblity.
i am mostly surprised that the code official did not require a design professional to seal the vault docs. the vault itself is not shown on the structural documents, it is on the architectural documents. as ser, we had to assume something for the foundations and have advised the architect (in writing) to require the an se seal on the performance design as would be required on any precast work. the only action on the part of the gc and supplier after months continues to be "no one else has ever asked for this before and we built hundreds of these and never have a problem..." while i would like to see a calc submittal for this, we would settle for sealed documents. we declined to offically review the shop drawings without a seal.
thanks again for all your comments.

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