Development of highly efficient building steel frame construction techniques that improve earthquake resistance. Full size experiments and results of demonstration obtained from the fabrication of model building steel frames

2002 ◽  
Vol 16 (12) ◽  
pp. 995-1002
Author(s):  
M Uchida ◽  
T Nakagomi ◽  
N Minami ◽  
S Iwasato
2021 ◽  
Vol 19 (6) ◽  
pp. 2483-2504
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu

AbstractThis paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.


2010 ◽  
Vol 168-170 ◽  
pp. 553-558
Author(s):  
Feng Xia Li ◽  
Bu Xin

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.


2020 ◽  
Vol 14 (2) ◽  
pp. 143-153
Author(s):  
Oksa Eberly ◽  
◽  
Sri Murni Dewi ◽  
Wisnumurti Wisnumurti ◽  
◽  
...  

This paper presents an experimental study on the behaviour of a braced steel frame with a proposed system: anticompression brace system (ABS) subjected to cyclic lateral loads. The ABS is proposed to deal with common brace buckling problems. In the study, split-K braced steel frames: with ABS and with ordinary brace system (OBS) were used as speciments. Cyclic loading tests were conducted to evaluate the performance of the proposed system in preventing the brace to buckle and to obtain the behaviour of the frame with ABS compared to the frame with OBS under cyclic quasistatic loading. From the cyclic tests, it was observed that the proposed system worked in preventing the braces to buckle, hence, the aimed state, “buckling prevention” was achieved. The results of the study also show that the frame with ABS had a lower initial stiffness compared to the frame with OBS, nevertheless, after exceeding drift ratio of 0.85% based on raw data or 0.64% based on fitted-curves, the frame with ABS exhibited good behaviour through lower degradations in stiffness and cyclic strength relative to the frame with OBS that experienced sudden and greater degradations.


Author(s):  
Erica C. Fischer ◽  
John Gambatese ◽  
Annabel B. Shephard

2012 ◽  
Vol 217-219 ◽  
pp. 1114-1118 ◽  
Author(s):  
Marco Valente

This study presents a displacement-based design procedure for seismic retrofitting of steel frames using buckling-restrained braces (BRB) to meet a given target displacement in the framework of the capacity spectrum method. The seismic performance of a six-storey steel frame equipped with BRB is investigated. Different storey-wise BRB distribution methods are proposed and the influence on the results of the design procedure is analyzed. Nonlinear dynamic analyses demonstrate the efficacy of the design procedure showing the improvements achieved by the retrofitting intervention using BRB. The maximum top displacement registered for the retrofitted frame under earthquake excitation coincides with the target displacement obtained in accordance with the design procedure. The introduction of buckling-restrained braces enhances the earthquake resistance of the steel frame, providing significant energy dissipation and the stiffness needed to satisfy structural drift limits.


2012 ◽  
Vol 226-228 ◽  
pp. 901-904
Author(s):  
Jin Zhu Yu ◽  
Ping Zhou Cao ◽  
Kai Wu ◽  
Ming Bao Min

Taking a six-storey steel frame construction as the research object, parameters under study are the horizontal space of braces’ nodes and the layout of vertical braces. Based on the analysis of the structural period, layer displacement and angles of storey drift, research on the influence of layout of braces on structural dynamic properties of large space buildings is conducted. The results show that when column spacing is larger, braces-setting contributes to significantly improve the structure’s lateral stiffness and reduce the section size of columns, and that the section size of braces can be reduced by shortening the horizontal space of braces’ nodes. Braces should be set between the columns as full as possible. It is better to set the vertical braces positioned in the center instead of on the side between the columns. The lateral stiffness is higher when braces are set concentratedly than dispersedly. It’s more economical to set the inclined braces uniformly.


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