Restoring force model of high‐strength concrete‐encased CFST composite columns

Author(s):  
Xiaojun Ke ◽  
Tingting Yang ◽  
Juntao Li
2012 ◽  
Vol 166-169 ◽  
pp. 1746-1751
Author(s):  
Kai Ze Ma

Based on the experimental results of twenty three high strength concrete-filled square steel tubular (HCFT) columns subjected to cyclic lateral load, the restoring force model of square HCFT columns is established. Through theoretical analysis and experimental results, the main parameters of the restoring force model which are axial load ratio, confinement effect coefficient as well as slenderness ratio are discussed. The theoretical method is put forward. The results show that the relation of elastic stiffness to degraded stiffness, the relation of ultimate bearing capacity to yielding loads are proportional with confinement effect coefficient, and inversely with axial load ratio as well as slenderness ratio. Many various influential factors are considered in the restoring force model of square HCFT columns. The model is close to the experimental results which can be conveniently applied for nonlinear dynamics analysis of composite structures.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Huang-bin Lin ◽  
Shou-gao Tang ◽  
Cheng Lan

A new method of characterizing the damage of high strength concrete structures is presented, which is based on the deformation energy double parameters damage model and incorporates both of the main forms of damage by earthquakes: first time damage beyond destruction and energy consumption. Firstly, test data of high strength reinforced concrete (RC) columns were evaluated. Then, the relationship between stiffness degradation, strength degradation, and ductility performance was obtained. And an expression for damage in terms of model parameters was determined, as well as the critical input data for the restoring force model to be used in analytical damage evaluation. Experimentally, the unloading stiffness was found to be related to the cycle number. Then, a correction for this changing was applied to better describe the unloading phenomenon and compensate for the shortcomings of structure elastic-plastic time history analysis. The above algorithm was embedded into an IDARC program. Finally, a case study of high strength RC multistory frames was presented. Under various seismic wave inputs, the structural damages were predicted. The damage model and correction algorithm of stiffness unloading were proved to be suitable and applicable in engineering design and damage evaluation of a high strength concrete structure.


2018 ◽  
Vol 21 (13) ◽  
pp. 2018-2029
Author(s):  
Xide Zhang ◽  
Zhiheng Deng ◽  
Xiaofang Deng ◽  
Jingwei Ying ◽  
Tao Yang ◽  
...  

To evaluate the ductility and energy dissipation capacity of the beam with concrete-encased steel truss, eight specimens with different types of steel truss, reinforcement ratios, and shear span ratios were tested by low-cyclic loading regime. The results indicated that beams with concrete-encased steel truss performed plumped load–displacement hysteretic loops as well as high strength and stiffness. Moreover, cross-web members improved their seismic behavior more effectively than non-cross-web members. Finally, the restoring force model of concrete-encased steel truss beam is proposed in accordance with the experimental results, which can be used to predict the load–displacement behavior of concrete-encased steel truss beam. The results could also provide a reference for the design and application of concrete-encased steel truss beam in practice.


2020 ◽  
Vol 164 ◽  
pp. 105765 ◽  
Author(s):  
Binglin Lai ◽  
J.Y. Richard Liew ◽  
Akshay Venkateshwaran ◽  
Shan Li ◽  
Mingxiang Xiong

2011 ◽  
Vol 71-78 ◽  
pp. 4203-4206
Author(s):  
Le Zhou ◽  
Hong Tao Liu

For the further study of bearing compressive capacity of GFRP tube filled with SHC(steel-reinforced high-strength concrete)columns subjected to eccentric compression, and analysis its whole bearing compressive process under eccentric compression. Based on the flat section assumption finite strip method, the calculating program of bearing eccentric compressive capacity of GFRP tube filled with SHC columns is proposed according to existing retrofit theory and related technical procedures. The relation curves of load-deformation is gotten using this calculating program, at the same time it can get the effect curves of concrete strength, slenderness ratio, eccentricity and containing bone rate to load-deformation. Calculations show that the ultimate bearing compressive capacity of composite column decreases with the increase of slenderness ratio, and elastic stage of component curve gradually shortens and stiffness gradually loses; The ultimate bearing compressive capacity of composite columns decreases with the increase of eccentricity; component ductility improves; the ultimate bearing compressive capacity of composite columns increases with the increase of concrete strength. The calculated results agree well with the experimental results and this study provides a basis for practical design.


2019 ◽  
Vol 23 (4) ◽  
pp. 794-809
Author(s):  
Yong Yang ◽  
Xing Du ◽  
Yunlong Yu ◽  
Yongpu Pan

The ultra-high-strength concrete-encased concrete-filled steel tube column consists of a concrete-filled steel tube core and a rectangle-shaped reinforced concrete encasement. This article presents the seismic performance analysis of ultra-high-strength concrete-encased concrete-filled steel tube columns subjected to cyclic loading. Based on the measured load-lateral displacement hysteresis curves of six ultra-high-strength concrete-encased concrete-filled steel tube columns and two conventional RC columns, the seismic behaviours, such as the ductility, energy dissipation, stiffness and load-bearing capacity, were analysed. The effects of the arrangement of the stirrups and the layout of the prestressed steel strips on the seismic performance of the composite columns were critically examined. The test results indicated that the ductility and energy dissipation performance of the ultra-high-strength concrete-encased concrete-filled steel tube columns were increased by 74.8% and 162.7%, respectively, compared with the conventional columns. The configuration of the prestressed steel strip increased the ductility of the composite column by 28.9%–63% and increased the energy consumption performance by 160.2%–263.3%. By reducing the stirrup spacing and using prestressed steel strips, the concrete-filled steel tube core columns could be effectively confined, leading to a great enhancement in ductility, energy dissipation, stiffness and load-bearing capacity.


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