wel-eng.
Structural
- Aug 15, 2019
- 3
Hello. I have decent experience with ASCE 41 eval/retrofit projects, but almost exclusively with the BPOE side of things. I understand that BPON requires the use of a Tier 3 procedure, which I'm also familiar with. What is unclear to me is if BOTH BSE-1N & BSE-2N and their associated performance objective levels must be considered for a retrofit project. For BPOE, both BSE-1E and BSE-2E are required (as updated in ASCE 41-17), but there is no parallel requirement for BPON, as far as I can tell. Perhaps it is implied, but not specifically called out in a "Scope of Assessment Required" table for Tier 3, like there is for Tier 1 & 2.
I understand that the IEBC requires the two-level performacnce objective when compliance with full seismic forces is triggered by an alteration, change of occupancy, etc. In my case, there's no triggered changes that would change risk category or occupancy.
I also understand that some retrofits are mandated by programs that define the performance objective levels for the engineers. In my case, this is part of the FEMA Hazard Mitigation Grant Program, which as far as I can tell, only includes general references to, "retrofit projects for existing buildings must be designed to meet or exceed the requirements in the latest published edition of ASCE 41." I cannot find much specificity beyond that.
We are building on work completed by a prior engineer under older editions of ASCE 41, which only considered BSE-1N. The easiest path forward would be to update the evaluation to the latest standard, but I fear that down the line the grant program will kick back the project for not considering BSE-2N as well. Before you ask, I've already called the local officer, but haven't heard back. If I get a definitive response from them, then great. But if not, then I want to make sure I'm proceding with the most appropriate approach. Currently leaning towards including both performance objectives and seismic hazards in the eval/retrofit, but am open to recommendations.
tldr does ASCE 41-17/23 require both BSE-1N & BSE-2N for BPON, or can you just select one?
Thanks!
I understand that the IEBC requires the two-level performacnce objective when compliance with full seismic forces is triggered by an alteration, change of occupancy, etc. In my case, there's no triggered changes that would change risk category or occupancy.
I also understand that some retrofits are mandated by programs that define the performance objective levels for the engineers. In my case, this is part of the FEMA Hazard Mitigation Grant Program, which as far as I can tell, only includes general references to, "retrofit projects for existing buildings must be designed to meet or exceed the requirements in the latest published edition of ASCE 41." I cannot find much specificity beyond that.
We are building on work completed by a prior engineer under older editions of ASCE 41, which only considered BSE-1N. The easiest path forward would be to update the evaluation to the latest standard, but I fear that down the line the grant program will kick back the project for not considering BSE-2N as well. Before you ask, I've already called the local officer, but haven't heard back. If I get a definitive response from them, then great. But if not, then I want to make sure I'm proceding with the most appropriate approach. Currently leaning towards including both performance objectives and seismic hazards in the eval/retrofit, but am open to recommendations.
tldr does ASCE 41-17/23 require both BSE-1N & BSE-2N for BPON, or can you just select one?
Thanks!