TY - JOUR
T1 - Force reduction factors for steel buildings with welded and post-tensioned connections
AU - Reyes-Salazar, Alfredo
AU - Llanes-Tizoc, Mario D.
AU - Bojorquez, Juan
AU - Bojórquez, Edén
AU - López-Barraza, Arturo
AU - Haldar, Achintya
N1 - Funding Information:
This paper is based on work supported by La Universidad Autónoma de Sinaloa (UAS) under grant PROFAPI-2014/174. Financial support from The University of Arizona is also appreciated. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the sponsors.
Publisher Copyright:
© 2016, Springer Science+Business Media Dordrecht.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - The seismic responses of steel buildings with perimeter moment resisting frames (MRF) with welded connections (WC) are estimated and compared to those of similar buildings with semi-rigid post-tensioned connections (PC). The responses are estimated in terms of ductility reduction factors (Rµ,), ductility demands (µG) and force reduction factors (R). Two steel model buildings, which were modeled as complex-3D-MDOF systems, were used in the study. Results indicate that the reduction magnitude of global response parameters is larger than that of local response parameters, contradicting the same reduction implicitly assumed in the static equivalent lateral force procedure, implying that non-conservative design may result. The value of 8 for R, suggested in many codes for ductile steel MRF, and the value of 1 suggested in the well known Newmark and Hall procedure for the ratio of R to µG, cannot be justified. The reason for this is that SDOF systems were used to model actual structures, where higher mode effects, energy dissipation and structural overstrength weren’t explicitly considered. The codes should be more transparent regarding the magnitude and the components involved in the force reduction factors. The seismic performance of steel buildings with PC may be superior to that of the buildings with WC, since their force reduction factors are larger and their ductility demands smaller, implying that PC buildings could be designed for smaller lateral seismic forces. The conclusions of this paper are for the particular structural systems and models considered. Much more research is needed to reach more general conclusions.
AB - The seismic responses of steel buildings with perimeter moment resisting frames (MRF) with welded connections (WC) are estimated and compared to those of similar buildings with semi-rigid post-tensioned connections (PC). The responses are estimated in terms of ductility reduction factors (Rµ,), ductility demands (µG) and force reduction factors (R). Two steel model buildings, which were modeled as complex-3D-MDOF systems, were used in the study. Results indicate that the reduction magnitude of global response parameters is larger than that of local response parameters, contradicting the same reduction implicitly assumed in the static equivalent lateral force procedure, implying that non-conservative design may result. The value of 8 for R, suggested in many codes for ductile steel MRF, and the value of 1 suggested in the well known Newmark and Hall procedure for the ratio of R to µG, cannot be justified. The reason for this is that SDOF systems were used to model actual structures, where higher mode effects, energy dissipation and structural overstrength weren’t explicitly considered. The codes should be more transparent regarding the magnitude and the components involved in the force reduction factors. The seismic performance of steel buildings with PC may be superior to that of the buildings with WC, since their force reduction factors are larger and their ductility demands smaller, implying that PC buildings could be designed for smaller lateral seismic forces. The conclusions of this paper are for the particular structural systems and models considered. Much more research is needed to reach more general conclusions.
KW - Ductility and force reduction factors
KW - Ductility capacity
KW - MDOF and SDOF systems
KW - Moment resisting frames
KW - Steel buildings
KW - Welded and semi-rigid post-tensioned connections
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U2 - 10.1007/s10518-016-9925-4
DO - 10.1007/s10518-016-9925-4
M3 - Article
AN - SCOPUS:84966263952
VL - 14
SP - 2827
EP - 2858
JO - Bulletin of Earthquake Engineering
JF - Bulletin of Earthquake Engineering
SN - 1570-761X
IS - 10
ER -