huangyhg

existing precast building
i am reviewing an existing building with precast double tees, ledger beams and columns. the superimposed design load is specified as 90 psf including a 3" concrete topping. that leaves slightly over 50 psf available for ll which matches the code required ll. even though there is block partitions on the 2nd floor, there is no load requirement for block partitions in the specified design load. there are also block partitions on the ground floor. the block partitions are generally built up tight to the structure.
was there ever a design philosophy years ago that allowed the block partition weight on the 2nd floor to be carried by the block partitions on the first floor, if it was built tight to the structure? if yes, won't that be a big problem if a building like that is remodeled and walls on the 1st floor are removed by an unsuspecting owner or architect?
in reviewing lots of older plans, learning at the feet of engineers who started their careers in 1927, 1944, 1947, 1963 and 1974, i don't ever recall seeing partitions used below a floor to support partitions above a floor if they weren't already the primary structural system....just not done.
i agree with jae, you can never count on the partitions on the lower floor to remain in the long term to support anything above, and besides, its often unlikely that the lower partitions would be of the same layout as the upper ones.
i thank both jae and karlt for their comments. i am in agreement with both of you but was shocked to find an existing building where an engineer apparently used the cmu partitions below for support.
i was just wondering if this practice was common.

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