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.

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.

Study on Reliability Evaluation Method of Existing CFST Arch Bridge

2012 ◽  
Vol 226-228 ◽  
pp. 1679-1682
Author(s):  
Yi Song Zou ◽  
Hai Tao Hou ◽  
Wei Peng
Keyword(s):  
System Reliability ◽  
Reliability Index ◽  
Evaluation Method ◽  
Reliability Assessment ◽  
Steel Tube ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Arch Bridges ◽  
Grading Standards ◽  
Bridge System

Based on reliability theory, the application calculation method of Concrete Filled Steel Tube (CFST) arch bridge system reliability index is studied. Select the most unfavorable load distribution in working condition of maximum moment and deflection at the mid-span, from the angle of strain energy, calculated the weights of CFST arch ribs component. On the basis of the grading standards of reliability assessment of the existing bridge components and the critical structures, CFST arch bridge system reliability assessment grading standards are constructed. CFST arch bridges reliability index are evaluated from two aspects (the arch ribs and segment) in this article. As the CFST arch bridge locates in the marine environment, corrosion environment is the serious level of C5-M, steel pipe corrosion is the major diseases of CFST, arch rib which on the corrosion conditions were assessed. The results show that the method can effectively assess the situation of CFST arch bridge.

Autoexcitation-Based Accelerometer Array for Interface Separation Detection of Concrete-Filled Steel Tubular Arch Bridge

2014 ◽  
Vol 578-579 ◽  
pp. 995-999 ◽  
Author(s):  
Sheng Shan Pan ◽  
Xue Feng Zhao ◽  
Zhe Zhang
Keyword(s):  
Surface Wave ◽  
Bearing Capacity ◽  
Efficient Method ◽  
Vibration Signal ◽  
Steel Tube ◽  
Engineering Problem ◽  
Test Method ◽  
Vibration Test ◽  
Arch Bridge ◽  
Cfst Arch Bridge

The separation between the filled-concrete and the steel tube would reduce tremendously the bearing capacity of the concrete-filled steel tubular (CFST) arch bridge. However, there is no efficient method to monitor and detect the separation so far, which is a great engineering problem we have to solve. Therefore, this paper firstly proposes a vibration test method aiming at the local modal of the steel tube. Distributed accelerometer array deployed along the tube is used to acquire the vibration signal induced by quantitative excitation via telecontrol. Changes in frequency and amplitude of the steel tube are selected as parameters for the separation detection based on the theory of surface wave transmission. This method can satisfy the demand of the real-time monitoring of interface separation of the CFST arch bridge.

A Method for Seismic Capacity Evaluation of CFST Arch Bridges

2011 ◽  
Vol 268-270 ◽  
pp. 377-382
Author(s):  
Kai Zhong Xie ◽  
Le Qin Qin ◽  
Wen Gao Lv
Keyword(s):  
Failure Modes ◽  
Steel Tube ◽  
Ground Movement ◽  
Seismic Capacity ◽  
Arch Bridge ◽  
Capacity Evaluation ◽  
Cfst Arch Bridge ◽  
Internal Forces ◽  
Arch Bridges ◽  
Capability Evaluation

Based on strength and ductility, the seismic capabilities of the chords of arch ribs, web members, horizontal integrations, suspenders and beams of suspenders of concrete filled steel tube (CFST) arch bridges are studied, then the seismic capability of the bridge is obtained. Firstly, the internal forces of the members are calculated respectively by finite element under the actions of gravity representative value and small earthquakes (0.05g). Then the ultimate bearing capacities, the ratio of ductility and the reduction coefficients of earthquake are obtained according to the failure modes. Finally, yield accelerations of ground movement are multiplied by the reduction coefficients of earthquake, which the resistance seismic capabilities of the members Ac are obtained. The seismic capability of bridge is the minimum Ac. Taking Nanning Yonghe Bridge that is a 346m CFST arch bridge as example, the seismic capability is evaluated that the bridge can resisted the earthquake which the acceleration of ground movement is respectively 0.677g. The results show that the method of seismic capability evaluation is a feasible and efficient method for seismic capability evaluation of CFST arch bridge.

A Study on Dynamic Performance of Concrete Filled Steel Tube Arch Bridges

2014 ◽  
Vol 1065-1069 ◽  
pp. 926-929 ◽  
Author(s):  
Xue Wen Dong ◽  
Qiu Yang Liu
Keyword(s):  
Analytical Method ◽  
Theoretical Study ◽  
Dynamic Performance ◽  
Steel Tube ◽  
Vibration Characteristic ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cfst Arch Bridge ◽  
Arch Bridges ◽  
Bridge Models

With the span of CFST (Concrete Filled Steel Tube) arch bridges getting much longer, the dynamic performance of them is becoming more and more advanced. In order to evaluate the structure of CFST arch bridges in a comprehensive way, it is necessary to take the dynamic performance of this kind of bridges into consideration. Methods of doing the dynamic analysis can be divided into two kinds: one is traditional theoretical analytical method, which is only suitable for simple arch bridge models; the other is FEM (Finite Element Methods), which is able to simulate the real structure and lead to more precise results. This paper attempts to study the calculation theory of free vibration characteristic of arch bridges through theoretical analytical method, and then it will do an empirical study on the dynamic performance of a CFST arch bridge by FEM to test the conclusion of theoretical study.

Study on Transverse Synchronization Control for Super-Breadth and Long-Span Basket Handle Arch Bridge when Vertically Rotating

2013 ◽  
Vol 438-439 ◽  
pp. 917-922
Author(s):  
Zhi Wei Sun ◽  
Xiao Guang Wu
Keyword(s):  
Steel Tube ◽  
Synchronization Control ◽  
The Finite Element Method ◽  
Arch Bridge ◽  
Long Span ◽  
Maximum Value ◽  
Cfst Arch Bridge ◽  
The Difference ◽  
Arch Bridges ◽  
Main Arch

Monitoring and controlling of vertical construction for main arch ribs is most important for concrete-filled steel tube (CFST) arch bridges due to high risk. Controlling the difference of elevation between the two main arch ribs has direct influence on the mechanical behavior of lateral brace, towers and temporary hinges at arch abutments of main piers. Therefore, transverse synchronization control is the main priority in vertical rotating construction phase. Taking a half-through CFST arch bridge in Shijiazhuang City as an example, this paper make a study of transverse synchronization control of the two main arch ribs during vertical rotation. The finite element method (FEM) software-Midas is employed to simulate the main arch ribs in rotation construction phase, and maximum value of the difference of elevation between the two main arch ribs is obtained to offer reference and basis of vertical rotation construction of this bridge.

scholarly journals Failure Modes Analysis of Stone Arch Bridges

2015 ◽  
Vol 9 (1) ◽  
pp. 442-449
Author(s):  
Song Jun ◽  
Wang Fumin ◽  
Shi Kang
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Ultimate Bearing Capacity ◽  
Scale Model ◽  
Arch Bridge ◽  
Loading Process ◽  
Bridge Safety ◽  
Destruction Mechanism ◽  
Arch Bar ◽  
Arch Bridges

A destruction test based on the bridge safety appraisal is one way to verify the failure law of an actual bridge. In this paper, a stone arch bridge in a 1:10 scale model and with a span of 60 m (namely, an arch bar of the same length as the object of test) has been tested, methods of its whole test and loading process introduced, and ultimate bearing capacity, deflection and development rules of cracks in the loading process figured out. With the clarification of destruction mechanism, the ultimate forms of disease and remaining height of section have been acquired and, finally, the destruction theory of stone arch bridges has been verified and optimized.

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.

The Study on Bearing Capacity Influence for the Steel Tube Deformation in CFST Arch Bridge

2012 ◽  
Vol 178-181 ◽  
pp. 2236-2239 ◽  
Author(s):  
De Rong Zeng ◽  
Tie Jun Wang
Keyword(s):  
Bearing Capacity ◽  
Critical Stress ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Reduction Factor ◽  
Analysis Software ◽  
Element Analysis ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Before And After

The theoretical formulas of the ultimate bearing capacity and critical stress of the deformed steel tube in a CFST arch bridge are gotten by the local section steel tube analysis and the elastic buckling analysis of steel tube, At the same time, the ultimate bearing capacity and critical stress of the deformed steel tube are computed by using ANSYS finite element analysis software and compared, which verifies the theoretical formulas are correctness and feasibility. Finally, a reduction factor formula of the ultimate bearing capacity of the tube before and after deformation is gotten; it directly reflected the reduction level of the ultimate bearing capacity of the deformed steel tube.

scholarly journals Experimental Study on Deformation Behavior and Compressive Strength of Concrete Cast in Steel Tube Arches under Low-Temperature Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tuo Shi ◽  
Nianchun Deng ◽  
Xiao Guo ◽  
Wen Xu ◽  
Shi Wang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Performance Test ◽  
Large Diameter ◽  
Test Site ◽  
Steel Tube ◽  
Design Strength ◽  
Curing Conditions ◽  
Expansive Agent ◽  
Arch Bridges

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.

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