Hi,
Based on NBCC 2015 4.1.8.11 4) single storey buildings with steel or wood deck as diaphragms can have a higher fundamental period compared to 4.1.8.11 3) as seen in the snap below. However, in the current RAM frame the Ta is only based on clause 3). In addition, if I user specify the period, it gets capped out on the design as 2* Ta for braced frames from clause 3). Is there a way to implement this or make the user override the current maximum Ta limit?
Thanks,
I see options to have Ta based on 4.1.8.11.3 a,b or c or you can specify Ta outright. In the US code if you use provisions for drift then T used won't be capped, but I still see a cap on T (<=2Ta) in NBCC. If you really need something else, then user defined story forces are your last resort.