Natural periods of braced steel frames designed to EC8

Download
2012
Günaydın, Egemen
A two-phase study was undertaken to investigate the fundamental period of concentrically braced steel frames (CBFs) designed according to Eurocode 8. In the first phase, typical office buildings were studied by conducting two types of designs which are called as iterative and non-iterative. Non-iterative design is composed of obtaining final period by designing the structure with lower bound expression in Eurocode 8 while iterative design is similar to the non-iterative one but an updating of periods was considered in order to converge assumed and final periods. Different overstrength provisions are considered in the study. Lower bound expression in Eurocode 8 results in shorter periods which indicates that this expression can be safely utilized. The lower bound represented by Tremblay (2005) is also admissible except for some cases including shorter periods. In the second phase, a simple expression is derived for estimating the design base acceleration for braced frames proportioned according to Eurocode 8. This method requires inelastic top story drift values which were obtained from structures designed in the first phase using iterative method. These drifts were represented by simple expressions utilizing data fitting techniques. The method gives suitable first order estimate for the design base acceleration.

Suggestions

Seismic Retrofit of Deficient RC Structures with Internal Steel Frames
ÖZÇELİK, RAMAZAN; Akpinar, Ugur; Binici, Barış (2011-12-01)
This paper describes an experimental study on internal steel frames (ISFs) to retrofit seismically deficient reinforced concrete (RC) frames. One reference and six strengthened frame specimens were tested under constant gravity load and cyclic lateral displacement excursions. Installation of the ISF with and without anchors to the RC frame was examined. Test results showed that the snug tight ISF installed inside an RC frame may suffice to realize the benefit of implementing ISFs. If the horizontal shear st...
Numerical studies on eccentrically braced frames
Kuşyılmaz, Ahmet; Topkaya, Cem; Sarıtaş, Afşin; Department of Civil Engineering (2014)
Numerical studies were performed on eccentrically steel braced frames to ascertain seismic performance factors and to examine dynamic characteristics of eccentrically braced frames (EBF). Pursuant to this goal a computer program which facilitates EBF designs was developed. In the first phase, the approximate period formula given in ASCE7-10 was evaluated and a technique based on global deformation characteristics was developed to improve the fundamental period estimates for EBFs. The results indicate that t...
Seismic performance of a special type of single-story eccentrically braced steel frame
Dicleli, Murat (SAGE Publications, 2008-02-01)
This research is aimed at studying the seismic response of a single story non-buckling eccentrically braced steel frame (NBF) in relation to conventional moment resisting frame (MRF) and concentrically braced frame (CBF). The NBF is intended to combine the advantages of MRF and CBF and eliminate most of the disadvantages pertinent to these frames. Nonlinear static pushover and time history analyses are conducted to assess the performance of the NBF compared to the performance of MRF and CBF. The analyses re...
Fundamental periods of steel concentrically braced frames designed to Eurocode 8
Gunaydin, Egemen; Topkaya, Cem (2013-08-01)
A two-phase research program has been undertaken to investigate fundamental natural periods of concentrically braced frames (CBFs) designed according to Eurocode 8 (EC8). In the first phase of the program, over 83,700 buildings were designed, and the accuracy of the lower bound expressions given in well-known design specifications was evaluated. The results indicated that the lower bound expressions given in EC8 and National Building Code of Canada (NBCC) are acceptable. Although all structures had periods ...
Mechanical behavior of CFRP confined low strength concretes subjected to simultaneous heating-cooling cycles and sustained loading
Erdil, B.; Akyüz, Uğurhan; Yaman, İsmail Özgür (Springer Science and Business Media LLC, 2012-01-01)
This study aims to present the mechanical behavior of carbon fiber reinforced polymers (CFRP) reinforced low strength cylindrical and prism concrete specimens under both heating-cooling cycles and sustained loading. Heating-cooling cycles range from -10 to 50A degrees C and the applied sustained load level is 40% of the ultimate strength of concrete. After 200 heating-cooling cycles and/or sustained load testing, specimens were tested to determine the mechanical behavior under uniaxial compression. The expe...
Citation Formats
E. Günaydın, “Natural periods of braced steel frames designed to EC8,” M.S. - Master of Science, Middle East Technical University, 2012.