Cyclic behavior of concrete‐encased high‐strength concrete‐filled steel tube composite walls: An experiment

2020 ◽  
Author(s):  
Jing Zhou ◽  
Xiaodan Fang ◽  
Yi Jiang
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Cyclic Behavior ◽  
Concrete Filled Steel Tube ◽  
Strength Concrete ◽  
Composite Walls

Experimental study on the seismic performance of composite columns with an ultra-high-strength concrete-filled steel tube core

2019 ◽  
Vol 23 (4) ◽  
pp. 794-809
Author(s):  
Yong Yang ◽  
Xing Du ◽  
Yunlong Yu ◽  
Yongpu Pan
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Concrete Filled Steel Tube ◽  
Composite Columns ◽  
Strength Concrete ◽  
Steel Strips

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.

scholarly journals Interfacial Bond Behavior of High Strength Concrete Filled Steel Tube after Exposure to Elevated Temperatures and Cooled by Fire Hydrant

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 150
Author(s):  
Zongping Chen ◽  
Jiyu Tang ◽  
Xingyu Zhou ◽  
Ji Zhou ◽  
Jianjia Chen
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Steel Tube ◽  
Water Cooling ◽  
Interfacial Bond ◽  
Concrete Filled Steel Tube ◽  
Bond Behavior ◽  
Strength Concrete

For the engineering structure in case of fire, a fire hydrant is generally used for extinguishing the fire. This paper presents an experimental investigation on interfacial bond behavior of high-strength concrete-filled steel tube (HSCFST) after exposure to elevated temperatures and cooled by fire hydrant using the pull-out test of 22 specimens. According to the experimental study, the failure mechanism of HSCFST exposed to elevated temperatures and water-cooling (ETWC) was revealed, the influence of various parameters on the bond behavior was analyzed, and the calculation formula of the bond strength of HSCFST subjected to ETWC was put forward. The results show that the load-slip curves of the loading end and the free end of the specimen are basically similar, and can be divided into three types of typical curves. In the push out test, the strain on the outer surface of the steel tube is exponentially distributed with its distance from the loading end. After ETWC exposure, the bond strength of the specimen is less affected by the concrete strength, which is inversely proportional to the anchorage length, and it is basically stable after the constant temperature duration is longer than 60 min. With the increase of the maximum temperature, the ultimate bond strength increases first, then decreases and then increases, and the residual bond strength increases first and then decreases. Besides, the study indicate that cooling method has significant influence on the bond behavior, compared with natural cooling specimens, the ultimate bond strength, residual bond strength, and shear bond stiffness of water-cooling specimens are smaller, and the interfacial energy dissipation capacity is larger.

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