huangyhg

should struct engs be concerned w/ floor flatness?
new building. the inspector is saying the elevated slab is just barely out of spec for floor flatness and floor levelness. is there any reason why the architect should be forwarding this issue to the structural engineer? never have heard of this problem on any project before.
i'd think as long as there isnt excess or a lack of concrete on the composite deck then that's all the struct engineer has to worry about correct?
check the deflections and the amount of concrete installed. if those are acceptble then the flatness is a serviceability decision for someone else to make.
for some reason i am not following your question. does it have almost too much dl deflection?
as haynewp stated, check your serviceability calculations to ensure they are to code and check that what is installed matches your design.
if all the numbers add up then in my opinion this is a contractor quality control issue and not a structural issue.
this is not a structural engineer concern if load requirements, deflections, etc. are met or adequate.
the architect may not have any idea on how to fix such a problem and is forwarding this to you for some information. if this is not the case, then this is a problem for the architect and contractor to work out.
who's job would it have been to write the specifictions that controlled the floor flatness?
i too would think that this is a serviceability issue, unless it is an issue that should have been dealt with in the specifications.
however at times judgement is required by all parties involved. for examble a l/175 deflection where a l/180 deflection is required would only be a 1/16" difference on a 40" span. in your case being slightly out of spec, might be critical, or it might be just a little out of spec.
sorry guys, i'm talking about deflections you can barely see. the ff and fl numbers is what the special inspector is complaining about.
the deck, beams, girders all fall within our normal deflection limits
loui1 - this type problem is common (from an owner's representative's perspective). sounds like the architect really wants is the engineer to make the decision (and take responsibility) for waiving the discrepancy. depending on what the specified numbers are, this could be a (technically) reasonable thing to do. if so, i suggest that the contractor be required to give a negotiated financial credit to the owner. if the contractor has a "problem" with this, he can always bear the cost to replace the floors...
as rarswc says, you need to find out who spec'd the ff/fl numbers. that should be spelled out in the statement of special inspections. on our jobs, the statement of special inspections is made by the eor.
also, we specify the ff/fl limits on the structural drawings, so for us, this would be a structural issue. we also say, in our specs, what is to be done of the concrete work doesn't meet the specification.
it would help to know what the building is being used for and the ff/fl criteria and measured values.
sounds as though the eor didn't set the limits, so the architect must have. if the owner/architect is unwilling to back off on the levelness spec, then the concrete spec should spell out what happens next.
bottom line: engineers don't care if the floor is flat as long as it still works structurally. architects do care. if they don't have an issue with the floor not being flat, then there is no problem.
i'd write an email to the architect saying that structurally we have no exception to leaving the floor as is. please review the floor flatness for architectural acceptability.