I am comparing design output from Nucor's concrete filled diaphragm design to Hilti's published information from ESR-2197. Nucor shows the same Pnf Nominal Capacity for the X-ENP-19 (in my case 1603# for 22 ga). Table 2 of the ESR lists multiple values for Omega. My interpretation is that the ASD fastener capacity to the frame (for earthquake loads) should be based on Omega = 2.3 from Table 2 (which matches AISI Table B1.1 value of Omega for screws and earthquake loading), and the allowable capacity of the concrete filled diaphragm should use Omega=3.25. However, it is not exactly clear from the table that my interpretation is correct. Can you confirm?
Hi Ken,
Table 2 values in ESR-2197 are in accordance with American Iron and Steel Institute (AISI) S310, North American Standard for the Design of Profiled Steel Diaphragm Panels. This is addressed in the Table of Contents, found on page 5 of the report and shown in the snippet below.
Tables 3 through 7 include the allowable diaphragm shears and flexibility factors for bare deck and the allowable diaphragm shears based on stability. Tables 8 through 9 include the allowable diaphragm shears and flexibility factors for concrete filled decks.
The strength reduction factor used to calculate the factored shear resistance for Power-Actuated Fasteners (PAF) is dependent on if the steel deck is concrete filled or bare, as it is tested as a diaphragm system. Hilti offers PROFIS Engineering which is a cloud-based software for designing structural connections, including baseplates, rebar, and masonry. This software includes a Diaphragm Design module which allows users to create and optimize diaphragm designs for steel roof/floor deck systems as well as generate a detailed report, including calculations based on their desired parameters.
Regards,
Ashley