https://communities.bentley.com/products/ram-staad/f/ram-staad-forum/168492/period-time-rangeWhat is the period time range of first mode of RC high rise buildings under seismic loads?en-USTelligent Community 12https://communities.bentley.com/thread/483222?ContentTypeID=1Wed, 26 Sep 2018 16:05:21 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:3f344ed8-71e1-4ada-9ea9-0105423952d4Seth Guthrie<p>In the US there is an approximate period value Ta that gives a decent estimate, but a Moment Frame structure might be significantly longer.</p> <p><img alt=" " src="/resized-image/__size/320x240/__key/communityserver-discussions-components-files/5932/ta_5F00_asce_5F00_7_2D00_10.png" /></p> <p>Staad can, of course, calculate the periods through eigensolution.&nbsp;<a href="/products/ram-staad/w/structural_analysis_and_design__wiki/29023/calculating-modes-and-frequencies">https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/29023/calculating-modes-and-frequencies</a>&nbsp;</p><div style="clear:both;"></div>