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The first interpretation is correct. Each story-length of column is treated as a unique element. In this case, the first story column supports two floors and the second story does not. -- Ronald Hamburger, SE Consulting Principal Simpson Gumpertz & Heger --
have a technical question about provision 4.7.3 in ASCE 7-22 (see provision below). "4.7.3 Heavy Live Loads Live loads that exceed 100 lb/ft2 (4.79 kN/m2) shall not be reduced. EXCEPTION: Live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20%,...
Regarding IEBC, I was actually referring to the change of occupancy and classification of work. I realize that I did not make this clear; my mistake! The crux is that there are a lot of Level 1 alterations with no change of occupancy where the project doesn't even have a structural engineer on...
ASCE 7 does not prohibit classificaton of server racks as Dead Load and could be interpretted as specifically permitting it. ASCE 7 Chapter 2 defines "Dead Load" as "Dead loads consist of the weight of all materials of construction incorporated into the building including, but not limited to,...
Thanks Christian for the response. In regards to IEBC triggers for reanalysis, it shouldn't change if the load is classified as dead load or live load. For example: if you design for 2000lb racks - the 5% IEBC triggers means you can put in 2100lb racks without reanalysis - whether the rack is...
Hello Stephan, I don't think I have a satisfying answer, but I tend to agree with the direction you're heading: a project-specific agreement with your owner and AHJ. A safe but conservative approach would be to consider the weight as a sustained SDL for seismic demands but use a LL factor on the...
Ronald, thank you for the response. Agreed that if those unknowns exist then live load is the appropriate classification. For data center projects, SEs work closely with the owner to establish the loading criteria since ASCE7 does not provide a prescribed load for server racks. Specifically,...
Stephen I believe there are a number of reasons that server racks should be considered live, as opposed to dead load. First, they are subject to change in configuration from year to year and from tenant to tenant, as new technology evolves and tenant needs change, resulting in chnage of weight....
Neutral Axis will be shifting with respect to live load that is the beam or slab shall be comes under reinforced or over reinforced. For design LL is converted to equivalent DL. I think it is enough for decision. Alex Thomas BSc AMIE civ FIE MASCE CEng