scholarly journals A Comprehensive Research of the Air-void Defect of Concrete-filled Steel Tube

2021 ◽  
Author(s):  
Chao Guo ◽  
Zhengran Lu
Keyword(s):  
Large Diameter ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Steel Tube ◽  
Welding Temperature ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Air Voids ◽  
Air Void ◽  
The Impact

Welded spiral steel tubes are adapted for use in a majority of the large-diameter concrete-filled steel tube (CFST) arch bridges due to technical as well as economic reasons. However, the welding temperature and other factors during the process of manufacturing of steel tube, initially result in a reduced spiral-welded seam (SWS) strength. Moreover, with the pumping of concrete into a steel tube, numerous deformities of the likes of laitance coating and air-voids occurred inevitably, particularly with the lack of air-entraining agent in China almost 20 years ago. This work makes use of ultrasonic scanning field experience to investigate the capacity of bearing within a repaired and reconditioned CFST arch bridge rib having defects such as air-void and reduced SWS strength under negligible compression of eccentric axial by carrying out its finite element model analysis of group. The outcome reveals that CFST bearing capacity is only minimally affected by the SWS strength as compared to concrete air-void, which can be ignored. The effect of air-voids and the nonlinear behavior of the constituents on the CFST behavior have also been probed into. The impact of the air-void on the rib capacity of bearing was investigated by conducting parametric studies. To conclude, we proposed a new index defining the ultimate strength of the rib for the defect, and presented a rather simple blueprint to determine the influence of air-void on the final strength of the arch bridge rib of CFST.

scholarly journals Effects of SWS Strength and Concrete Air Void Composite Defects on Performance of CFST Arch Bridge Rib

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhengran Lu ◽  
Chao Guo
Keyword(s):  
Bearing Capacity ◽  
Ultimate Strength ◽  
Large Diameter ◽  
Steel Tube ◽  
Scale Model ◽  
Welding Temperature ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Arch Bridges ◽  
Air Void

Most large-diameter concrete-filled steel tube (CFST) arch bridges adopt spiral-welded steel tubes for technical and economic reasons. However, during the steel tube manufacturing process, the welding temperature and other factors lead to a decreased spiral-welded seam (SWS) strength initially. Furthermore, for the CFST arch bridges using ordinary concrete, the laitance and air void defects inevitably appear, especially 20 years ago when there was no air-entraining agent in China. This paper presents a group of scale model experiments and finite element model analysis of the bearing capacity of a serviced CFST arch bridge rib with decreased SWS strength and concrete air void composite defects, under small eccentric axial compression on ultrasonic scanning field data. Parametric analyses were also performed to investigate the influence of the air void and SWS strength on the bearing capacity of the rib. Finally, a new ultimate strength index of the rib with composite defects was proposed, and a simplified formula was presented to estimate the effects of the air void and SWS strength decrease on the ultimate strength of the CFST arch bridge rib.

Impact Factor Statistics Analysis of Concrete Filled Steel Tube Arch Bridge Considered Random Roughness of Bridge Deck

2015 ◽  
Vol 648 ◽  
pp. 80-88
Author(s):  
Xiang Wei Hao ◽  
Feng Ma ◽  
Qing Yang Ma
Keyword(s):  
Impact Factor ◽  
Bridge Deck ◽  
Steel Tube ◽  
Statistic Analysis ◽  
Coupling Vibration ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Random Roughness ◽  
Vehicle Impact ◽  
The Impact

The essence of the axle coupling vibration in case of random bridge deck is random vibration, therefore, it is quite necessary to research the effect of vehicle impact on basis of statistic analysis. With some large concrete-filled steel tube arch bridge as the object, by applying a self-made analysis program on axle coupling vibration that was demonstrated by a dynamic test, a dynamic response analysis on axle was implemented for many groups of random roughness swatches. On basis of the analysis result, a statistic analysis was conducted for the dynamic impact effect of bridge under the conditions of different deck status and vehicle speeds, in the determination of vehicle speed and roughness, the impact factor obeys the normal distribution. The analysis result shows that, the level of deck status may apparently affect the mean value and the MSD(mean square deviation), the differences of vehicle impact factors in case of different assurance rates are large. It will effectively improve the reasonableness and scientificalness of the value of a vehicle impact factor to determine the impact factor according to the level of bridge importance and a statistic analysis method.

Sensitivity Analysis on Dynamic Properties of Large Span Concrete-Filled Steel Tube Arch Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 1976-1979
Author(s):  
Hang Sun ◽  
Xiao Jian Han ◽  
Xiu Yun Gao
Keyword(s):  
Dynamic Properties ◽  
Steel Tube ◽  
Design Parameters ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Space Model ◽  
Long Span ◽  
Current Design ◽  
Arch Bridges ◽  
The Impact

The calculation formula of the vertical fundamental frequency of arch bridge has been given in current design codes, in which the rise-span ratio is the only variable on condition that the structure mass and stiffness are known. However, the dynamic properties of long-span concrete filled steel tube arch bridges have their own characteristics, which are influenced by a series of factors. Thus this article establishes a space model of a concrete-filled steel tube arch bridge. By analyzing the main design parameters’ influence on the structure dynamic properties, including rise-span ratios, arch-axis coefficient and wide-span ratios, some of conclusions has been made, which can be used for further research of the impact effect and earthquake dynamic response, and provide the necessary basis for the dynamic design of bridges of this kind

Dynamic Response of a Heterotypic Concrete Filled Steel Tube Arch Bridge Subjected to Moving Vehicles

2011 ◽  
Vol 255-260 ◽  
pp. 1696-1700
Author(s):  
Yan Li ◽  
Xin Yi Huang
Keyword(s):  
Surface Roughness ◽  
Dynamic Response ◽  
Impact Factor ◽  
Damping Ratio ◽  
Steel Tube ◽  
Impact Factors ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Moving Vehicles ◽  
The Impact

As a new type structure, the dynamic behavior of the irregular concrete filled steel tube arch bridge under moving vehicles was rarely studied. In this paper, taking the bridge crossing Yitong river in Changchun of China as an example, the dynamic response of the bridge is investigated by the self-compiling vehicle-bridge coupled vibration analysis program. The surface roughness and vehicle speed are considered in the analysis. The results show that impact factors of the bridge increase as surface roughness deteriorated; the impact factor varies obviously for the different component; the tension impact factor of the short suspender is larger than that of long ones; damping ratio of structure has little effect on the impact factors. The research conclusions can be referred in the design and assessment for the similar bridges.

scholarly journals Temperature Load Parameters and Thermal Effects of a Long-Span Concrete-Filled Steel Tube Arch Bridge in Tibet

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Tuo Shi ◽  
Jielian Zheng ◽  
Nianchun Deng ◽  
Zheng Chen ◽  
Xiao Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Thermal Effects ◽  
Thermal Load ◽  
Concrete Strength ◽  
Large Diameter ◽  
Steel Tube ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Average Temperature ◽  
Cfst Arch Bridge

Zangmu Bridge is a concrete-filled steel tube (CFST) arch bridge along the Sichuan-Tibet railway in Tibet, with a main span of 430 m. Owing to the unique temperature conditions in Tibet, there have been no large-scale experimental studies on the thermal load design of CFST bridges in this area. Therefore, to determine the thermal load calculation parameters and thermal effects of Zangmu Bridge, a long-term continuous field test was conducted to measure the temperature variations in a test arch with the same pipe diameter. The test results were then compared with current design specifications and relevant literature. Finally, the thermal effects in a CFST arch bridge were analysed using the finite element method. According to the results, the following recommendations were made: (1) the average temperature of concrete in the pipe after the formation of concrete strength should be used to calculate the closure temperature of CFST arch bridges in Tibet; however, the standard calculation formula was still applicable; (2) the daily average temperature in extreme weather should be taken as the maximum and minimum effective temperature; (3) we presented recommended values for the influence range and gradient temperature for a single large-diameter pipe; and (4) a refined finite element model that included the arch base should be used to verify the temperature effects during bridge design.

scholarly journals Static and dynamic evaluation of a butterfly-shaped concrete-filled steel tube arch bridge through numerical analysis and field tests

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110446
Author(s):  
Gang Wu ◽  
Wei-Xin Ren ◽  
Ya-Fei Zhu ◽  
Syed M Hussain
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Model ◽  
Field Tests ◽  
Element Model ◽  
Steel Tube ◽  
Model Errors ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cfst Arch Bridge

The butterfly-shaped concrete-filled steel tube (CFST) arch bridge is an irregular bridge with unique esthetics. In this paper, this new shape of CFST arch bridge is introduced, and a refined three-dimensional finite element model (FEM) is established to evaluate static and dynamic behavior of the bridge. In order to reduce model errors, the FEM is calibrated according to numerical analysis and field tests. Static calculation results show that the butterfly-shaped bridge has good structural performance. The bending moment and axial force of the arch ribs increase when the camber angle of suspender changing from 15° to 50°. Dynamic test is carried out by ambient vibration testing under traffic and wind-induced excitations. The modal parameters of the bridge were calculated by the stochastic subspace identification method in the time domain. In terms of natural frequencies and mode shapes, the FEM analysis was validated by experimental modal analysis. The updated model thus obtained can be treated as a baseline finite element model, which is suitable for long term monitoring and safety evaluation of the structure in different severe circumstances such as earthquakes and wind loading in future.

scholarly journals Artificial Neural Network-Based Method for Seismic Analysis of Concrete-Filled Steel Tube Arch Bridges

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhen Liu ◽  
Shibo Zhang
Keyword(s):  
Neural Network ◽  
Finite Element Method ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Seismic Analysis ◽  
Steel Tube ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cfst Arch Bridge ◽  
Artificial Neural

Seismic analysis of concrete-filled steel tube (CFST) arch bridge based on finite element method is a time-consuming work. Especially when uncertainty of material and structural parameters are involved, the computational requirements may exceed the computational power of high performance computers. In this paper, a seismic analysis method of CFST arch bridge based on artificial neural network is presented. The ANN is trained by these seismic damage and corresponding sample parameters based on finite element analysis. In order to obtain more efficient training samples, a uniform design method is used to select sample parameters. By comparing the damage probabilities under different seismic intensities, it is found that the damage probabilities of the neural network method and the finite element method are basically the same. The method based on ANN can save a lot of computing time.

Investigation on the dynamic impact factor of a concrete filled steel tube butterfly arch bridge

2021 ◽  
pp. 113614
Author(s):  
Shiqiang Qin ◽  
Jiacheng Feng ◽  
Yun-Lai Zhou ◽  
Chao Li ◽  
Xuejin Huo ◽  
...  
Keyword(s):  
Impact Factor ◽  
Steel Tube ◽  
Dynamic Impact ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Dynamic Impact Factor
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