Theoretical and numerical analysis on the ultimate bearing capacity of CFRP-confined CFSST stub columns

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hongyuan Tang ◽  
Junlong Chen ◽  
Zhaoyang Yue ◽  
Yigang Jia ◽  
Zhijun Yuan
2013 ◽  
Vol 690-693 ◽  
pp. 742-746
Author(s):  
Peng Wu ◽  
Jian Feng Xu ◽  
Jun Hai Zhao ◽  
Qian Zhu ◽  
Su Wang

Based on unified strength theory, the mechanical behavior of core-concrete of concrete-filled square steel tubular stub columns was analyzed. Through controlling the constraint effect between square steel tube and core-concrete by width-thickness ratio, the ultimate bearing capacity formula for concrete-filled square steel tubular stub columns under axial compression was proposed, and the influencing factors of which was also discussed. The rationality of proposed formula was proved from the comparison of the analytical results obtained in this paper and experimental data.


2021 ◽  
Vol 13 (23) ◽  
pp. 13166
Author(s):  
Xusen Li ◽  
Jiaqiang Zhang ◽  
Hao Xu ◽  
Zhenwu Shi ◽  
Qingfei Gao

Prestressed high-strength concrete (PHC) pipe piles have been widely used in engineering fields in recent years; however, the influencing factors of their ultimate bearing capacity (UBC) in multilayer soil need to be further studied. In this paper, a static load test (SLT) and numerical analysis are performed to obtain the load transfer and key UBC factors of pipe piles. The results show that the UBC of the test pile is mainly provided by the pile shaft resistance (PSR), but the pile tip resistance (PTR) cannot be ignored. Many factors can change the UBC of pipe piles, but their effects are different. The UBC of the pipe pile is linearly related to the friction coefficient and the outer-to-inner diameter ratio. Changes in the pile length make the UBC increase sharply. Low temperatures can produce freezing stress at the pile–soil interface. The effect of changing the Young modulus of pile tip soil is relatively small.


2011 ◽  
Vol 317-319 ◽  
pp. 2258-2265
Author(s):  
Jian Min Chen ◽  
Xiao Dong Hao ◽  
Zu Chang Song

Based on the present tecnology of pile, a method of compacted forming concrete pile applied in the subsea base is studied. Using the method of finite different the procedure of compacted forming at the end of steel pipe pile has been simulated in the particular geology soil, the effects of the elastic modulus, cohesion, friction and dilation on the compacted behaviour are aquired and the bearing capacity has been calculated. The results show that the ultimate bearing capacity of this pile increases approximate 3 times bigger than the steel pipe pile with the same dimentions, in addition, its curve of Q-S is smooth and ultimate feature point is indistinct, which proves that this tecnology of compacted forming concrete pile is able to increase the bearing capacity prominently.


Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 154
Author(s):  
En Wang ◽  
Yicen Liu ◽  
Fei Lyu ◽  
Faxing Ding ◽  
Yunlong Xu

Recycled aggregate concrete-filled steel tubular (RACFST) columns are widely recognized as efficient structural members that can reduce the environmental impact of the building industry and improve the mechanical behavior of recycled aggregate concrete (RAC). The objective of this study is to investigate the behavior of recycled aggregate concrete-filled circular steel tubular (RACFCST) stub columns subjected to the axial loading. Three-dimensional finite element (FE) models were established using a triaxial plastic-damage constitutive model of RAC considering the replacement ratio of recycled aggregates. The FE analytical results revealed that the decreased ultimate bearing capacity of RACFCST stub columns compared with conventional concrete infilled steel tubular (CFST) columns was mainly due to the weakened confinement effect and efficiency. This trend will become more apparent with the larger replacement ratio of recycled aggregates. A practical design formula of the ultimate bearing capacity of RACFCST stub columns subjected to axial load was proposed on the basis of the reasonably simplified cross-sectional stress nephogram at the ultimate state. The derivation process incorporated the equilibrium condition and the superposition theory. The proposed equation was evaluated by comparing its accuracy and accessibility to some well-known design formulae proposed by other researchers and some widely used design codes.


2021 ◽  
Vol 1 (107) ◽  
pp. 21-31
Author(s):  
A. Thakur ◽  
R.K. Dutta

Purpose: After a thorough study of literature it is concluded that the studies related to unskirted/skirted octagonal footings on sand have not yet been investigated. Thus, this paper presents a numerical analysis to assess the ultimate bearing capacity of the unskirted, unskirted-embedded, singly and doubly skirted octagonal footings resting on different sands (S1, S2, and S3). The length of skirt and depth of the embedded footing were varied from 0.0B to 1.5B. Design/methodology/approach: The numerical square and octagonal footing with singly and doubly skirted footing models were developed using Plaxis 3D software. Findings: The results of the doubly skirted octagonal footings ultimate bearing capacity were marginally higher in comparison to the singly skirted footing at all normalised skirt depths as well as for all sands up to a Ds/B ratio 0.25 beyond which the increase in the ultimate bearing capacity in case of doubly skirted footing was appreciable. Research limitations/implications: The results presented in this paper were based on numerical analysis. However, for the actual footings the soil placement and compaction, details of skirt construction and the stress level will be different from the numerical analysis. Further investigations using full-scale numerical models simulating field size footings were recommended to generalize the results. Originality/value: No such study on singly and doubly skirted octagonal shaped footings were conducted so far. Hence, an attempt was made in this article to predict the bearing capacity of those footings using Plaxis 3D.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xiao Guo ◽  
Hongwei Wang ◽  
Kaizhong Xie ◽  
Tuo Shi ◽  
Dan Yu

In order to study the influence of corrosion rate and shear span ratio on reinforced concrete beam, a numerical analysis method of corroded reinforced concrete beam was put forward. Bond-slip relationship formula between reinforcement and concrete was suggested. A three-dimensional finite element model of corroded reinforced concrete beam was established. Calculation method of ultimate bearing capacity for reinforced concrete beam was suggested. Ultimate bearing capacity experiment on 14 corroded reinforced concrete beams with different corrosion rates and shear span ratios was carried out. Numerical analysis results and experimental results were compared and analyzed. The results show that, for reinforced concrete beams with different corrosion rates and shear span ratios, load-deflection curve can be divided into elasticity stage and plasticity stage. With the increase of corrosion rate and shear span ratio, ultimate bearing capacity of corroded reinforced concrete beam decreased. When shear span ratio was 3.0, if corrosion rate increased by 1%, experimental value of ultimate bearing capacity decreased by 1.002 kN. When shear span ratio was 2.4, if corrosion rate increased by 1%, experimental value of ultimate bearing capacity decreased by 1.849 kN. The numerical analysis method put forward in this paper was feasible, and the suggested ultimate bearing capacity calculation method for reinforced concrete beam has a high accuracy.


2011 ◽  
Vol 261-263 ◽  
pp. 1215-1219 ◽  
Author(s):  
Xiu Bin Gong ◽  
Qing Lai Fan ◽  
Yong Jie Xu

Based on the framework of the FEM, the three-dimensional numerical analysis for evaluating the efficiency of pile groups of large diameter bored cast-in-place pile is conducted in this paper. The effect of the pile numbers and pile spacing on the efficiency of pile groups is obtained by studying the ultimate bearing capacity behavior of different arrangements of pile groups under vertical loading. Then they are compared with the calculated results gained by the formula of the efficiency factor of the pile groups based on superimposed stresses. The findings can serve as a reference for the design of large diameter bored cast-in-place pile.


2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Wenyu Hou ◽  
Fengchi Wang ◽  
Lianguang Wang

This paper presents the experimental and numerical analysis of damaged steel beams strengthened with prestressed CFRP sheet or only strengthened with CFRP sheet. The test results showed that damaged level had a significant effect on the stiffness, yield load, and ultimate bearing capacity. And using prestressing CFRP sheet to strengthen damaged steel beam could increase the ultimate bearing capacity. The numerical analysis results showed that the damaged level had a significant effect on the stiffness and ultimate bearing capacity. The strengthened steel beam with the damaged level could exceed the steel beam without damage by about 10% in the ultimate bearing capacity. The ultimate bearing capacity would increase about 8% when the flange or web thickness increased per 1 mm. The ultimate bearing capacity would increase about 3% when the thickness or width of CFRP sheet increased per 0.05 mm or 10 mm. The bearing capacity would increase about 1.5% when the prestressed degree increased about 7%.


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