Hi wannabeSE,
I prefer to get a tabulated result as im not confindent checking Mode shapes animation visually. Do you know how extract these info which relates the rotation and or displacement to its corresponding mode shape, i cant find any related info in Result table output as well as in the...
Hi Everyone,
Im doing Dynamic Analysis in Etabs to capture the first 3 modes(response) of the Building, it is understood that Mode 1 and Mode 2 should be translational in orthogonal directions and Mode 3 is more likelt rotation. My question is, is there any tabulated output maybe a Node...
Hi Everyone,
Im doing Dynamic Analysis in Etabs to capture the first 3 modes(response) of the Building, it is understood that Mode 1 and Mode 2 should be translational in orthogonal directions and Mode 3 is more likelt rotation. My question is, is there any tabulated output maybe a Node...
Hi All,
May i have your thoughts with regards to application of accidental Torsion in ETABS, as seen in the attached it is undestood tha the story force F is applied to the center of mass CM and has a distance ex from the center of stiffness/rigidity. As for the accidental torsion, my question...
Hi Guys,
Im currently working on a project where the structural arrangement composed of Lateral Force Resisting System around the perimeter and Gravity Internal Frames. Section 1633.2.4 paragraph 2 of UBC 97 states that "For elements not part of the lateral-force-resisting system, the forces...
Hi bookowski,
I’ve found some reference Serviceability limit states under wind load (Engineering Journal) by Lawrence G. Griffis which I think it’s a good reference, however I have a hard time dealing with the grafts, what is shown there are grafts the most common one is Root-Mean-Square (RMS)...
Hi Guys,
May I have your thoughts is regards to serviceability check of building motion for wind loads particularly motion perception (vibration, acceleration). Tall buildings are usually exposed to wind and in this regards acceleration should be taken into account (motion perception). Common...
Hi Guys,
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...
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...
The approximate fundamental period as per UBC should not be greater than 1.3Ta for seismic zone 4 and 1.4Ta for seismic zone 1,2,3,. and also "The restriction in SEAOC 88 that the base shear calculated using the rational period shall not be less than 80% of the value obtained by using the...
The approximate fundamental period as per UBC should not be greater than 1.3Ta for seismic zone 4 and 1.4Ta for seismic zone 1,2,3,. and also "The restriction in SEAOC 88 that the base shear calculated using the rational period shall not be less than 80% of the value obtained by using the...
Hi JAE,
Thanks for the reply, going back to my question these means that the effective stiffness factor for column is not precise and can be calculated nor reduced per equation 10-8.
Thanks for the input,
As per section 10.10.4.1 of ACI318 refers to stiffness modification factor for compression and flexural members/elements, particularly for columns 0.7Ig indicates it won't crack. I find this factor a bit unconservative to capture the actual response of the building, is it okay if i make a...
Does anyone here has an idea with regards to the relationship between Peak Ground Acceleration (PGA) and Short period mapped spectral acceleration Ss per IBC requirement, and the relationship between PGA and UBC zoning, what specific section on IBC and UBC, Thank you,
Does anyone here has an idea with regards to the relationship between Peak Ground Acceleration (PGA) and Short period mapped spectral acceleration Ss per IBC requirement, and the relationship between PGA and UBC zoning, what specific section on IBC and UBC, Thank you,
Assuming that per soils report the seismic source is between A and B,is it possible to interpolate the values of seismic source A and B to come up with a reasonable input value?.
DCBII,
Thanks a lot for further explaining, is it okay if say the ratio of Static Base Shear EQX and dynamic base shear SPECX (EQX/SPECX) is almost 90, coz some of my recent job I'm arriving with a scale factor of 10 or lesser, but this time I'm arriving with scale factor of 90.
PicoStruc,
What it if I'm arriving with a scale factor of say 90, coz some of my jobs I'm arriving with 10 or below scale factor. Is it acceptable it the scale factor is around 90 or greater?
