Diaphragm Action
Diaphragm Action
(OP)
Hi Guys,
May I have your thoughts in my etabs model particularly the diaphragm action of floor plate (rigid diaphragm), assuming the lateral resisting system are the ones along the perimeter of the building and the rest of the frames are for gravity (internal frames). As shown on the attached sketch (Figure 1) is the axial response of the beams opposing the seismic loads whereas Figure 2 is the modified model having internal beams as gravity beams and to idealize the diaphragm action to transmit the seismic/in plane forces to resisting element (collector/drag-strut) and eventually to lateral resisting system what I did is to release the axial resistance (axial stiffness modifier = 0.01) of the internal beam thereby the seismic load is transferred to the outer frame which is the lateral resisting frame. Is figure 2 model is correct or acceptable.
May I have your thoughts in my etabs model particularly the diaphragm action of floor plate (rigid diaphragm), assuming the lateral resisting system are the ones along the perimeter of the building and the rest of the frames are for gravity (internal frames). As shown on the attached sketch (Figure 1) is the axial response of the beams opposing the seismic loads whereas Figure 2 is the modified model having internal beams as gravity beams and to idealize the diaphragm action to transmit the seismic/in plane forces to resisting element (collector/drag-strut) and eventually to lateral resisting system what I did is to release the axial resistance (axial stiffness modifier = 0.01) of the internal beam thereby the seismic load is transferred to the outer frame which is the lateral resisting frame. Is figure 2 model is correct or acceptable.






RE: Diaphragm Action
RE: Diaphragm Action
RE: Diaphragm Action
RE: Diaphragm Action
Thanks for the input I appreciate it,
@dcarr82775, the internal frames are frame (physical), my intension is that the lateral frames are the ones along perimeter and the internal frames are just gravity frames (gravity beams and columns), please note that the stiffness modification factor for lateral frames are as follows 0.7Ig for columns, 0.35Ig for beams and 0.25Ig for slabs, and the stiffness modification factor for gravity frames (internal frames 0.001Ig for columns and 0.35Ig for beams and also the axial stiffness modifier for gravity beams is 0.01 this way the external frames soak up all in plane forces coming from the diaphragm as shown attached.