Deflection distribution estimation of the main arch of arch bridges based on long-gauge fiber optic sensing technology

Deflection of the main arch of arch bridges is one of the main indices for supporting the alignment after construction and evaluating the structural performance. The existing sensing technology and analysis method for deflection monitoring have developed, but it is still difficult to monitor the deflection of the main arch of a long-span arch bridge with great height difference between measuring points. On the contrary, in recent years, with the outstanding advantages of fiber optic sensing technologies, a long-gauge fiber Bragg grating sensing technology has been used in structural health monitoring due to its characteristics, including reflecting the macro and micro information and being connected into network. For these reasons, the long-gauge fiber Bragg grating sensing technology is proposed to develop a method to monitor the deflection of the main arch of arch bridges. A curvature load method for deflection distribution estimation using strain measurements is proposed. It deduces the expression of the complex relation between the strain and the deformation on the main arch element and then separates the coupled strain on the element through the specific sensor layout. A series of simulation tests of the deck arch bridge, half-through bridge, and through arch bridge was conducted. It is concluded that the proposed method can not only be applied to these long-span arch bridges but also can identify the static and dynamic deflections of the main arch effectively.

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Fiber-Optic Sensing Systems: Fiber-Bragg Grating Sensor and Swept Laser Interrogation Platform

2005 International Conference on Microelectronics ◽

10.1109/icm.2005.1590019 ◽

2006 ◽

Author(s):

K. Hsu

Keyword(s):

Fiber Bragg Grating ◽

Fiber Optic ◽

Fiber Bragg Grating Sensor ◽

Bragg Grating ◽

Sensing Systems ◽

Fiber Optic Sensing ◽

Bragg Grating Sensor

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Ultimate Bearing Capacity Analysis of Long-Span Continuous Stone Arch Bridge

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.3800 ◽

2011 ◽

Vol 71-78 ◽

pp. 3800-3805

Author(s):

Da Lin Hu ◽

Kai Jiang ◽

Qi Xin Sun ◽

Lin Han

Keyword(s):

Bearing Capacity ◽

Safety Assessment ◽

Ultimate Bearing Capacity ◽

Failure Characteristics ◽

Arch Bridge ◽

The Past ◽

Long Span ◽

Arch Bridges ◽

Mechanical Performances ◽

Main Arch

In the past 50 years, many long-span continuous stone arch bridges have been built in China. Analysis of mechanical performances and load capacities of long-span continuous stone arch bridges has important significances for the safety assessment of the similar bridges. 3D elastoplastic finite element method is employed to analyze ultimate bearing capacity of a three-span arch bridge with sandstone masonry in this paper. The characteristics of structural geometric and material nonlinearities and cracking and crushing of the masonry are taken into account. Compared with single-span arch bridge, both the coaction of spandrel structure and main arch and the influence of loading arrangements on ultimate bearing capacity is analyzed. The failure characteristics of the structure under the ultimate load are also introduced. The analysis results and conclusions can be referenced for the safety assessment of similar bridges.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.917 ◽

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.

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The foaming dynamic characteristics of polyurethane foam

Journal of Cellular Plastics ◽

10.1177/0021955x19864374 ◽

2019 ◽

Vol 56 (3) ◽

pp. 279-295

Author(s):

Cui Zhang ◽

Xinglin Tong ◽

Chengwei Deng ◽

Hongqiao Wen ◽

Di Huang ◽

...

Keyword(s):

Polyurethane Foam ◽

Reaction Temperature ◽

Fiber Optic ◽

Polymer Composite Material ◽

Reaction Process ◽

Bragg Grating ◽

Sensing Technology ◽

Foaming Power ◽

Fiber Optic Sensing ◽

Expansion Force

Polyurethane foam is a kind of polymer composite material. The foaming turgidity and reaction temperature of polyurethane foam are closely related to its mechanical properties. According to our present knowledge, this study is the first time that fiber optic sensing technology has been applied to monitor the dynamics change in the foaming turgidity and reaction temperature of polyurethane foam during its preparation. The effects on the foaming expansion force, contractile force, and reaction temperature are studied through changing proportion of water among the ingredients of the polyurethane foam. The results have shown that the fiber optic Bragg grating wavelength varies due to the reaction temperature and foaming power. In the reaction process, the foaming expansion force can make the maximum wavelength change of fiber optic Bragg grating 1–3.5 nm, equivalent to 1000–3541 micro strain. And the highest temperature of the reaction was 42.6°C. The wavelength shifts of the fiber optic Bragg gratings were closely related to the reaction temperature and foaming power. The results show that fiber optic sensing technology can be used for the online kinetics monitoring of the reaction process of polyurethane foam plastics. The data obtained from the fiber optic Bragg grating could be used for the design and performance prediction of new polyurethane foam materials.

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