Collapse-Resistance Measure for the Bottom Frame Structure under Earthquake

2014 ◽  
Vol 580-583 ◽  
pp. 1676-1679
Author(s):  
Duo Zhi Wang ◽  
Jun Wu Dai ◽  
Ruo Chen Shan
Keyword(s):  
Quantitative Analysis ◽  
Seismic Performance ◽  
Seismic Waves ◽  
Earthquake Damage ◽  
Frame Structure ◽  
Stiffness Ratio ◽  
Collapse Resistance ◽  
Resistance Measure ◽  
Wing Walls ◽  
Bottom Frame

The bottom frame structure, with serious earthquake damage, occupies a large proportion in the houses collapsed in earthquakes. However, because it is economic and practical, it is still widely used. Based on the understanding of the seismic performance of bottom frame structure, this paper determines to study seismic measures of the bottom frame structure. The current seismic measures can be divided into two major categories: strengthening key components and avoiding key components, therefore this paper adopts the method of strengthening parts which are easy to collapse for reinforcement, under the premise of meeting the stiffness ratio between reasonable layers, adds wing wall to improve the capacity of resisting collapse of the structure and pinpoints the efficiency of adding wing wall in the capacity of resisting collapse through quantitative analysis. Although there are differences in the improvement of the capacity of resisting collapse under different seismic waves, adding wing walls reasonably can greatly improver the anti-collapse capacity of the structure..

Study on Rational Ratios of Lateral Stiffness for Masonry Building with Frame Structure at First Two Stories

2012 ◽  
Vol 174-177 ◽  
pp. 2012-2015
Author(s):  
Xiao Long Zhou ◽  
Ying Min Li ◽  
Lin Bo Song ◽  
Qian Tan
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Shear Wall ◽  
Calculation Model ◽  
Frame Structure ◽  
Wall Structure ◽  
Masonry Building ◽  
Lateral Stiffness ◽  
Stiffness Ratio ◽  
Lateral Stiffness Ratio

There are two typical seismic damage characteristics to the masonry building with frame shear wall structure at first two stories, and the lateral stiffness ratio of the third storey to the second storey is one of the key factors mostly affecting the seismic performance of this kind of building. However, some factors are not considered sufficiently in current Chinese seismic codes. According to the theory of performance-based seismic design, the seismic performance of this kind of structure is analyzed in this paper by taking time-history analysis on models which with different storey stiffness ratios. The results show that when the lateral stiffness ratio controlled in a reasonable range, the upper masonry deformation can be ensured in a range of elastic roughly, and the bottom frame can be guaranteed to have sufficient deformation and energy dissipation capacity. Finally, according to the seismic performance characteristics of masonry building with frame shear wall structure at first two stories, especially the characteristics under strong earthquakes, a method of simplified calculation model for the upper masonry is discussed in this paper.

scholarly journals Shaking Table Test for Evaluating the Seismic Performance of Steel Frame Retrofitted by Buckling-Restrained Braces

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tingting Wang ◽  
Jianhua Shao ◽  
Chao Zhao ◽  
Wenjin Liu ◽  
Zhanguang Wang
Keyword(s):  
Seismic Performance ◽  
Shear Force ◽  
Seismic Waves ◽  
Shaking Table Test ◽  
Steel Frame ◽  
Shaking Table ◽  
Frame Structure ◽  
Acceleration Response ◽  
Buckling Restrained Brace ◽  
Interstory Drift

To investigate the seismic performance of buckling-restrained braces under the earthquake action, the shaking table test with a two-story 1/4 scale model is carried out for the ordinary pure steel frame and the buckling-restrained bracing steel frame with low-yield-point steel as the core plate. The failure modes, dynamic characteristics, acceleration response, interstory drift ratio, strain, shear force, and other mechanical properties of those two comparative structures subjected to different levels of seismic waves are mainly evaluated by the experiment. The test results show that under the action of seismic waves with different intensities, the apparent observations of damage occur in the pure frame structure, while no obvious or serious damage in the steel members of BRB structure is observed. With the increase in loading peak acceleration for the earthquake waves, the natural frequency of both structures gradually decreases and the damping ratio gradually increases. At the end of the test, the stiffness degradation rate of the pure frame structure is 11.2%, while that of the buckling-restrained bracing steel frame structure is only 5.4%. The acceleration response of the buckling-restrained bracing steel frame is smaller than that of the pure steel frame, and the acceleration amplification factor at the second story is larger than that at the first story for both structures. The average interstory drift ratios are, respectively, 1/847 and 1/238 for the pure steel frame under the frequent earthquake and rare earthquake and are 1/3000 and 1/314 for the buckling-restrained bracing steel frame, which reveals that the reduction rate of lateral displacement reaches a maximum of 71.71% after the installation of buckling-restrained brace in the pure steel frame. The strain values at each measuring point of the structural beam and column gradually increase with the increase of the peak seismic acceleration, but the strain values of the pure steel frame are significantly larger than those of the buckling-restrained bracing steel frame, which indicates that the buckling-restrained brace as the first seismic line of defense in the structure can dramatically protect the significant structural members. The maximum shear force at each floor of the structure decreases with the increase in height, and the shear response of the pure frame is apparently higher than that of the buckling-restrained bracing structure.

scholarly journals Seismic Performance of an Efficient Scissor-Jack-Damper Configuration

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Lihua Zhu ◽  
Pengyu Guo ◽  
Chenglong Hua ◽  
Shiyu Shan
Keyword(s):  
Mechanical Behavior ◽  
Seismic Performance ◽  
High Efficiency ◽  
Steel Frame ◽  
Earthquake Damage ◽  
Frame Structure ◽  
Magnification Factor ◽  
Practical Engineering ◽  
Steel Frame Structure ◽  
Damping Systems

Energy-dissipating or damping systems have been widely used in new and retrofitted structures for reducing earthquake damage to structural frames. Most damping devices were installed using diagonal or chevronbrace configurations, until the development of toggle-brace and scissor-jack configurations. This paper presents a modified scissor-jack-damper configuration with substantially improved efficiency. The mechanical behavior of the efficient scissor-jack-damper configuration is analyzed theoretically, and a formula for the displacement magnification factor of the configuration is proposed. A steel-frame specimen installed with the efficient scissor-jack-damper configuration was tested to verify the accuracy of the formula. The seismic responses of an uncontrolled steel-frame structure and of two controlled structures, installed with a diagonal brace and efficient scissor-jack-damper configurations, were analyzed using SAP2000. The high efficiency of the proposed scissor-jack-damper configuration is thus verified for practical engineering situations.

Analysis on the Seismic Behavior of Extended End-Plate Connections of Steel Frame Structure

2012 ◽  
Vol 193-194 ◽  
pp. 1405-1413 ◽  
Author(s):  
Zhu Ling Yan ◽  
Bao Long Cui ◽  
Ke Zhang
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Seismic Behavior ◽  
Frame Structure ◽  
End Plate ◽  
Rigid Connection ◽  
Extended End Plate ◽  
Plate Connections ◽  
Steel Frame Structure

This paper conducts analysis on beam-column extended end-plate semi-rigid connection joint concerning monotonic loading and cyclic loading of finite element through ANSYS program, mainly discussed the influence of parameters such as the form of end plate stiffening rib on anti-seismic performance of joint.

scholarly journals Analysis of the robustness of a steel frame structure with composite floors subject to multiple fire scenarios

2021 ◽  
pp. 136943322199249
Author(s):  
Riza Suwondo ◽  
Lee Cunningham ◽  
Martin Gillie ◽  
Colin Bailey
Keyword(s):  
Progressive Collapse ◽  
Three Dimensional ◽  
Steel Structure ◽  
Frame Structure ◽  
Worst Case ◽  
Collapse Resistance ◽  
Fire Scenarios ◽  
Element Approach ◽  
The One ◽  
Steel Frame Structure

This study presents robustness analyses of a three-dimensional multi-storey composite steel structure under the action of multiple fire scenarios. The main objective of the work is to improve current understanding of the collapse resistance of this type of building under different fire situations. A finite element approach was adopted with the model being firstly validated against previous studies available in the literature. The modelling approach was then used to investigate the collapse resistance of the structure for the various fire scenarios examined. Different sizes of fire compartment are considered in this study, starting from one bay, three bays and lastly the whole ground floor as the fire compartment. The investigation allows a fundamental understanding of load redistribution paths and member interactions when local failure occurs. It is concluded that the robustness of the focussed building in a fire is considerably affected by the size of fire compartments as well as fire location. The subject building can resist progressive collapse when the fire occurs only in the one-bay compartment. On the other hand, total collapse occurs when fire is located in the edge three-bay case. This shows that more than one fire scenario needs to be taken into consideration to ensure that a structure of this type can survive from collapse in the worst-case situation.

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