Quantification of seismic performance factors for self-centering controlled rocking special concentrically braced frame

2016 ◽  
Vol 25 (14) ◽  
pp. 700-723 ◽  
Author(s):  
Navid Rahgozar ◽  
Abdolreza S. Moghadam ◽  
Armin Aziminejad
1999 ◽  
Vol 26 (4) ◽  
pp. 379-394 ◽  
Author(s):  
M S Medhekar ◽  
DJL Kennedy

The seismic performance of single-storey steel buildings, with concentrically braced frames and a roof diaphragm that acts structurally, is evaluated. The buildings are designed in accordance with the National Building Code of Canada 1995 and CSA Standard S16.1-94 for five seismic zones in western Canada with seismicities ranging from low to high. Only frames designed with a force modification factor of 1.5 are considered. Analytical models of the building are developed, which consider the nonlinear seismic behaviour of the concentrically braced frame, the strength and stiffness contributions of the cladding, and the flexibility, strength, and distributed mass of the roof diaphragm. The seismic response of the models is assessed by means of a linear static analysis, a response spectrum analysis, a nonlinear static or "pushover" analysis, and nonlinear dynamic time history analyses. The results indicate that current design procedures provide a reasonable estimate of the drift and brace ductility demand, but do not ensure that yielding is restricted to the braces. Moreover, in moderate and high seismic zones, the roof diaphragm responds inelastically and brace connections are overloaded. Recommendations are made to improve the seismic performance of such buildings.Key words: analyses, concentrically braced frame, dynamic, earthquake, flexible diaphragm, low-rise, nonlinear, seismic design, steel.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ergang Xiong ◽  
Kun Zu ◽  
Qian Zhang

To study the seismic performance of self-centering concentrically braced frame (SC-CBF) structure, the static elastoplastic analysis, low-cycle repeated loading analysis, and elastoplastic time-history analysis were conducted for a four-story SC-CBF structure, compared with the traditionally concentrically braced frame (CBF) structure. The influences of different GAP stiffnesses and cross-sectional areas of prestressed tendon were investigated on the self-centering and seismic performance of the SC-CBF structure. The results show that the SC-CBF structure has a strong lateral resistance, a small base shear under earthquake action, and a slight residual drift after unloading. The SC-CBF structure has a better ductility than the CBF structure. The displacement of the SC-CBF structure under the action of rare and extremely rare earthquakes is large, and the structure can dissipate more energy; the interstory drift is large, but the residual drift is small, exhibiting its ideal seismic and self-centering performance. However, the mechanical behavior of prestressed tendons is significantly affected by the stiffness of the GAP. The mechanical and seismic performances of the overall structure are slightly affected by the stiffness of the GAP, but the cross-sectional area of the prestressed tendons has a remarkable influence on the overall performance of the structure.


2014 ◽  
Vol 41 (7) ◽  
pp. 579-593
Author(s):  
A. Caruso-Juliano ◽  
A. Gallagher ◽  
T.E. Morrison ◽  
C.A. Rogers

A general overview of the seismic performance of representative single-storey concentrically braced frame (CBF) buildings designed using the 1965 National Building Code of Canada and the 1965 S16 Canadian Standards Association Steel Structures for Buildings Standard was obtained through the use of nonlinear time history dynamic analyses and the testing of brace elements obtained from buildings constructed in the 1960s. The study comprised 16 representative buildings subjected to 20 site selected ground motions for three locations; Halifax (Nova Scotia) low seismicity, Montreal (Quebec) moderate seismicity, and Abbotsford (British Columbia) high seismicity. Incremental dynamic analyses were performed using various failure criteria as obtained from the test data; brace net-section fracture, bolt shear, block shear, bolt bearing and brace yielding. Fragility curves were created and the probability of failure was defined. The performance of the structures designed for Abbotsford was unsatisfactory for all of the brace connection failure mechanisms. In contrast, because of the lower current seismic hazard in Montreal, the 16 archetypical buildings demonstrated better performance. In Halifax the buildings performed well, based on the identified failure criteria. It was necessary to strengthen the roof diaphragms for all buildings to carry 2010 NBCC design level seismic forces.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Roberto Javier Merino Vela ◽  
Emanuele Brunesi ◽  
Roberto Nascimbene

Nonstructural components play an important role in the correct functioning of industrial facilities, which may suffer greatly from earthquake-induced actions, as demonstrated by past seismic events. Therefore, the correct evaluation of seismic demands acting upon them is of utmost importance when assessing or designing an industrial complex exposed to seismic hazard. Among others, nonlinear time history analyses (NLTHA) of structural systems including nonstructural elements and floor response spectra are well-known methods for computing these actions, the former being more accurate and the latter being less onerous. This work focuses on deriving floor spectra for a steel special concentrically braced frame (SCBF), which is a common type of lateral-load resisting system for industrial frames. The results are used to compute the seismic actions on a small liquid storage tank mounted on the case study frame. Additionally, the results are compared to those obtained by modeling the structure and the tank together, that is, by modeling the tank explicitly and incorporating it within the model of the support structure. To this end, a simple model, consisting of two uncoupled single degree-of-freedom systems, is used for the tank. The floor spectra resulting from both approaches are compared to establish differences in the behavior of the structure and nonstructural element/component. Finally, the seismic demand on the tank—obtained by direct and indirect analyses—is compared to that obtained by applying ASCE 7-10 and Eurocode 8 prescriptions.


Sign in / Sign up

Export Citation Format

Share Document