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

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.

2011 ◽  
Vol 268-270 ◽  
pp. 377-382
Author(s):  
Kai Zhong Xie ◽  
Le Qin Qin ◽  
Wen Gao Lv

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.


2014 ◽  
Vol 1065-1069 ◽  
pp. 926-929 ◽  
Author(s):  
Xue Wen Dong ◽  
Qiu Yang Liu

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.


2013 ◽  
Vol 438-439 ◽  
pp. 917-922
Author(s):  
Zhi Wei Sun ◽  
Xiao Guang Wu

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhengran Lu ◽  
Chao Guo

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.


2011 ◽  
Vol 255-260 ◽  
pp. 962-966
Author(s):  
Fan Xing ◽  
Lin Zhao ◽  
Ya Zhe Xing

In view of huge destructibility of the near-fault ground motions, structures with long natural vibration period are liable to fall into nonlinear reaction stage. Based on a full understanding of the near-fault seismic spectrum characteristics, the out-of-plane seismic response of a long span concrete-filled steel tube (CFST) arch bridge was studied in depth, and the research result could offer a reference for near-fault aseismic design.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhen Liu ◽  
Shibo Zhang

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.


2013 ◽  
Vol 639-640 ◽  
pp. 1025-1028
Author(s):  
Zhong Quan Zou ◽  
Xu Wang ◽  
Zhi Mei Wang

Concrete Filled Steel Tube(CFST) is widely used in civil engineering structures because of its superior mechanical performance. Yet the mechanical behavior of CFST is highly depended on the construction quality of the filled concrete. Hence it is very important for the inspection of the construction quality of the filled concrete in CFST structures. In this paper, the ultrasonic testing technique was used to detect the defect of the filled concrete of a CFST arch bridge. During the inspection, the ultrasonic transducer was moved along the circumference of the cross-section of the arch, and the defect of the concrete was comprehensively judged by detecting the change of sonic time, sonic amplitude and sonic frequency. Based on the analysis of the ultrasonic transmission path, the influences of different defects on the sonic time, sonic amplitude and sonic frequency were discussed. The detecting results were verified by core-drilling method. The verification showed that different kinds of defects defected by ultrasonic testing was in good accordance with the drilling samples, which demonstrates the adaptability of the ultrasonic detection technique in the construction quality inspection of CFST structures.


2012 ◽  
Vol 178-181 ◽  
pp. 2405-2411
Author(s):  
Li He ◽  
Yong Jiu Qian

A variety of conventional weapons equipped with explosive are used to destroy the significant long-span arch bridge. Because of the special function of the weapons and the complexity of the arch bridge, the damage results with the features of uncertainty and fuzzy are assessed with fuzzy theory. Combined with the standards for technical condition evaluation of highway bridges and wartime specific requirements, the fuzzy mathematical model based on the fuzzy mathematics theory and method is established to judgment comprehensively the arch technical condition. The hirarchy fuzzy comprehensive evaluation method is applied to determine the technical state grade of the damaged arch bridge. The method of damage evaluation provides the effective reference for the emergency repairmen of the arch bridges.


2014 ◽  
Vol 578-579 ◽  
pp. 995-999 ◽  
Author(s):  
Sheng Shan Pan ◽  
Xue Feng Zhao ◽  
Zhe Zhang

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.


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