While live loads are defined, they are still unknown. A heavy piece or furniture could be considered a live load, such as a piano. The other consideration is impact, if I am in my basement and one of my kids jumps off the couch, it is like an earthquake overhead! There is still a place for...
In my professional opinion, "uncertainty" is the key word when referring to the "MINIMUM" Design Loads for Buildings and Other Structures coupled with simplified analyses. ASCE states that "it does not intend, nor should anyone interpret, ASCE's standards to replace the sound judgment of a...
Christian, As you are likely aware, the road to LRFD has been a long one, with some recent updates. The road starts back in the 1960s, when ACI introduced "Strength" design as an appendix in 318-64. In 71 this became the primary method and ASD moved to an appendix. Steel was next, in the...
Christian, as you note the 0.42 factor in IBC is historic and ties back to ASD design. The ASCE 7 committee has not discussed updating this in IBC, but it could become a topic of discussion for the ASC 7-28 Committee, which will be formed in a few months. Look for a call for volunteers...
The road to LRFD is slow and arduous, but we're almost there with updated maps and 1.0 load factors for wind, snow (as of 7-22), and seismic. I assume ultimate rain loads are around the corner. Now, dead load is an actual estimation of weight, so the 1.2 and 0.9 factors are important. But...
ASCE 7 has moved away from drift checks based on a fixed ratio of design wind loads. The motivation for this is understandable. As the commentary (Section CC1.2 in ASCE 7-10) suggests, different projects may have different risk tolerance for serviceability failure. For example, I am working...
There is overlap between components covered by ASCE Chapters 13 and 15. Philosophically, Chapter 13 covers relatively small components supported above grade in a building and Chapter 15 covers nonbuilding structures (large components) supported at grade. As I mentioned there is overlap between...
Currently API is using chapter 13 of ASCE for design of pipe supports regardless of whether they are attached to a building or not. In my mind pipe supports not attached to a building would be designed per chapter 15 and not chapter 13 as they are not a mechanical/electrical component of a...