The Ultimate Strength of the Concrete-Filled Tubular (CFT) Section Columns

2012 ◽  
Vol 204-208 ◽  
pp. 899-902
Author(s):  
Young Bong Kwon ◽  
In Kyu Jeong ◽  
In Kyu Kwon

This paper describes design strength of concrete-filled tubular (CFT) section columns accounting for local buckling of steel skin. The local buckling has a negative effect on the ultimate compression strength based on the yield stress of steel skin and nominal compressive strength of in-filled concrete. A squash load formula for CFT stub columns is proposed to account for the post-local-buckling strength of steel skin. A compressive strength formula for filled-in concrete accounting for the confining effect of steel skin and strength ratio between filled-in concrete and steel skin is also proposed. The squash loads predicted by the proposed strength formula for the direct strength method were compared with the AISC (2010) and Eurocode4 (2004). The comparison showed that the squash load formula proposed can predict conservatively the squash load of circular and rectangular CFT columns with local buckling

Author(s):  
K. Sobajima ◽  
J. Nie ◽  
T. Miyashita ◽  
S. Okada ◽  
N. Takeshima ◽  
...  

2011 ◽  
Vol 243-249 ◽  
pp. 1179-1185
Author(s):  
Jing Fu Kang ◽  
Chun Xia Yan

This research investigated the influences of rubber content and water-cement ratio on the compressive strength of roller compacted rubberized concrete (RCR). The mix design of RCR was made by replacing same volume of sand with rubber chips based on the control concrete mix. Four rubber contents (50 kg/m3, 80 kg/m3, 100 kg/m3 and 120 kg/m3) and six water-cement ratios (0.30, 0.35, 0.40, 0.45, 0.50 and 0.55) were used. The specimen cubes were tested in compression at 28d with the load continuously and automatically measured until failure. Test results show that RCR exhibits low compressive strength but a ductile and plastic failure mode, the more the rubber used, the more the compressive strength reduced and the larger toughness obtained. Same as normal concrete, the compressive strength of RCR is also directly related to the water-cement ratio,the smaller the water-cement ratio, the higher the compressive strength. Based on the experimental results, a strength formula was developed to estimate the strength of RCR as a function of the cement strength, water-cement ratio and the rubber content.


2019 ◽  
Vol 262 ◽  
pp. 06008 ◽  
Author(s):  
Małgorzata Pająk

The main objective of the paper was to provide more information about the influence of fibers coming from the end-of-life tires on the behaviour of concrete. Because of their untypical geometrical characteristic they are not eagerly applied as concrete reinforcement. Considering the amount of used tires, the management of this waste would he beneficial for the environment. The paper deals with the typical floor concrete reinforced with three dosages of fibers equal to: 30kg/m3, 40kg/m3 and 60kg/m3. The compressive and flexural mechanical parameters of RSFC were studied. The waste fibers with the shape dissimilar to manufactured fibers did not have a negative effect on the properties of the mix in a fresh state. The compressive strength was slightly affected by the fibers, meanwhile the pronounced influence of RSF on the post-peak flexural parameters was noted. Those parameters increased proportionally with the amount of fibers. However, the scatters in the flexural tests results were increasing with the fibers content. The investigations indicate that the fibers from the end-of-life tires could he applied as a concrete reinforcement. The values of flexural parameters which can be further applied to structural calculations were shown.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tuo Shi ◽  
Nianchun Deng ◽  
Xiao Guo ◽  
Wen Xu ◽  
Shi Wang

Taking the construction of a concrete-filled steel tube (CFST) arch bridge (part of the Sichuan-Tibet Railway) in low temperatures as the test site, firstly the deformation performance test of concrete was carried out. Following this initial testing, measurement of compressive strength and shrinkage performance was conducted in large-diameter CFSTs under a variety of curing conditions. Experimental results showed that the expansion effect of Ca-Mg composite expansive agent in concrete was better than that of other expansive agents at any stage. Under low-temperature curing (0°C), the sampling strength of the large-diameter CFSTs reached 73.5% of the design strength at 28 d in the presence of a nonthermal curing system. The design strength itself was reached, when a curing system involving a thermal insulation film was applied, and use of this film also led to improvements in concrete shrinkage. The results suggested that a Ca-Mg composite expansive agent, combined with an insulation film curing system, should be the technique selected for concrete pumping construction of CFST arch bridges in Tibet.


2011 ◽  
Vol 201-203 ◽  
pp. 2900-2903 ◽  
Author(s):  
Chui Huon Tina Ting ◽  
Hieng Ho Lau

Built-up sections are used to resist load induced in a structure when a single section is not sufficient to carry the design load for example roof trusses. In current North American Specification, the provision has been substantially taken from research in hot-rolled built-up members connected with bolts or welds [1]. The aim of this paper is to investigate on built-up back-to-back channels stub columns experimentally and theoretically using Effective Width Method and Direct Strength Method. Compression test was performed on 5 lipped channel and 5 back-to-back channels stub columns fabricated from cold-formed steel sheets of 1.2mm thicknesses. The test results indicated that local buckling is the dominant failure modes of stub columns. Therefore, Effective Width Method predicts the capacity of stub columns compared to Direct Strength Method. When compared to the average test results, results based on EWM are 5% higher while results based on DSM are 12% higher for stub column.


2014 ◽  
Vol 894 ◽  
pp. 55-59
Author(s):  
Abdoullah Namdar ◽  
Fadzil Mat Yahaya ◽  
Kok Jun Jie ◽  
Lim Yen Ping

One of waste agriculture materials is oil palm shell ash. It has been producing in high quantity in palm oil mill, and for storage of that an investment requires. In this paper, an attempt has been made to analysis effect of oil palm shell ash on compressive and flexural strength of cement mortar. The compressive strength and flexural strength of cement mortar has been measured. To improve accuracy of work 50% cement and 50% fine sand has been proposed in cement mortar mix design. The results have been indicated that the effect of OPS ash on flexural and compressive strength of cement mortar is not same. The deflection, load sustainability and time to failure for compressive strength have independent fluctuation of flexural strength. The positive and negative effect of OPS ash on mechanical properties of cement mortar has been observed. The morphology of crack failure has not been investigated. The work can be continued with many waste agriculture materials. Keywords: waste agriculture, deflection, load sustainability, time to failure.


2021 ◽  
Vol 167 ◽  
pp. 108214
Author(s):  
Ahmed Sharhan ◽  
Weiyong Wang ◽  
Xiang Li ◽  
Hisham Al-azzani

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