چکیده:
Steel braces hasve a growing application in building structural and industrial
constructions. In the recent years there has been a lot of research done about
performance and behavior of these types of structures in elastic and plastic states
whos outcomes have been effective on improvement of design criteria and
implementation quality of structures. On the other hand since near fault seisms have
different properties from those of far fault seisms and issues related to effects of near
and far fault have been recently separated in different regulations, seismic behavior
of steel constructions designed on the basis of lateral load resisting concentrated
bracing system and regulation of designing resisting constructions to seism (Standard
No. 800-3rd edition) has been studied in this research. Frames studied are of 5, 10 and
15-floor structues from which one frame has been selected to be studied and time
history non-linear dynamic analysis method and effects of two types of near and far
fault accelerogram have been used. Values of displacement and floors reverse anchor
and base shear in both modified (with scale) and unmodified (without scale) states of
near and far fault accelerograms were calculated and the results were compared.
خلاصه ماشینی:
"578 15-floor 6- Models Analysis and Results After doing time history non-linear dynamic analysis for accelerograms in two states of unscaled and scaled under near and far fault seisms based on Standard No. 2800 of Structures Design Guideline, data analysis Table 4.
Mean of maximum displacement of floors in non-linear dynamic analysis for 5-floor frame under near and far fault modified and unmodified accelerograms Table 5.
Mean of floors’ maximum displacement in non-linear dynamic analysis for 10-floor frame under modified and unmodified near and far fault accelerograms Mean Floors’ maximum Drift Figure 7.
Floors’ mean of maximum displacement in non-linear dynamic analysis for 15-floor frame under modified and unmodified near and far fault accelerogram Table 19.
Studying under modified (scaled) near and far fault floors’ maximum displacement and drift and shear, floors reverse anchor and base shear for some near fault accelerograms are lower than those of far fault ones and also means obtained from near fault accelegrograms in some floors are irregularly lower than those of far fault ones.
In scaled state according to Standard No. 2800 of Structures Design Guideline accelerograms mean base shear amplification factor fro studied 15-floor frame is 1.
In studying under modified near and far fault according Standard No. 2800 of Structures Design Guideline maximum floors displacement and drift and shear and reverse anchor and base shear under some of near fault accelerograms was lower than those of far fault ones and mean values obtained from near fault accelerograms in some floors was lower than mean values obtained from far fault accelerograms."