analysis of multi-story buildings(10 to 60 story high)

[monchie]

Hello,

Is it possible to analyze and design a multi-story bldg(say 10 to 60 story high) without non-linear analysis. Or should I say, designing a skyscraper(up to 100 story high) using only "ETABS Plus" as the main analysis engine(because ETABS Plus has no non-linear capabilities). Any ideas will be greatly appreciated.

Regards,

 

[johnbridge231]

Since the conditions to perform a linear analysis, sure you could, but this seems to be hard to reach, since the vertical loads will cause a moment on the top floors, if considering a typical skyscraper. In this case you cannot avoid a non linear analysis. This can be checked by calculating the ratio (N*e)/(V*h) for every story, where N and V the axial and shear forces for the story (under a lateral load and the participating vertical loads), e the horizontal displacement and h the story height. If this value is more than 20%, a non linear analysis should be perfomed mandatorily.
Typically, a height much larger (>>) to the plan dimensions leads to the above.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[dadomago75]

Hi,
sorry if I ask, but when both of you say "non linear analysis" you mean "geometrical non linearity" (P-Delta) right?
Becasue as I know the Non-linear analysis is what it's commonly called Pushover.
Even for a skyscraper you can use just linear analysis with a RSA.

 

[johnbridge231]

Of course we mean geometrically non-linear analysis, as material non linearities usually do not arise when analyzing new buildings.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html