Fiber Optic Sensing of Prestressed-Prism-Reinforced Continuous-Composite Concrete Beams for Bridge Deck Application

Author(s):  
Edward G. Nawy ◽  
Benxian Chen

This investigation involves the identification and use of a novel type of fiber optic sensor in nondestructive testing and monitoring of the deformation behavior of critical sections of structural concrete elements and transforming them into smart systems. Deformational behavior of high-performance-concrete continuous-composite beams reinforced with prestressed prisms was studied and instrumented using fiber optic Bragg grating sensors. Such elements are useful as components of continuous bridge decks where prevention of cracking in the negative moment regions is essential to maintaining the integrity of a bridge. An experimental technique using Bragg grating sensors to evaluate the behavior of the investigated elements at service load stages and the potential of this technique for on-line, real-time monitoring of existing constructed concrete structures are presented. Four continuous beams 5791 mm (19 ft) long with two equal 2743-mm (9-ft) clear spans were tested to failure. High-performance concrete with compressive strength fc’ in excess of 90 MPa (13,000 psi) was used for both the precast prestressed prisms and the main beams cast in situ. Experimental results were compared with theoretical evaluations obtained from nonlinear analysis. Parametric study was conducted to further identify the primary variables that affected the structural performance of such composite T-sections.

1997 ◽  
Vol 503 ◽  
Author(s):  
Edward G. Nawy ◽  
P. E.

ABSTRACTThis investigation involves the identification and use of a novel type of fiber optic sensors in monitoring the deformation behavior of critical sections of the structural concrete elements and transforming them into smart systems. Basic operating principles of the Bragg-grating sensors identified in this work are proved to be feasible. Deformational behavior was studied of high performance concrete composite beams reinforced with prestressed prisms and instrumented with Bragg Grating fiber optic sensors. The experimental techniques using those sensors for evaluating their behavior at service load stages, and the potential of this technique for on-line, real-time monitoring of existing constructed concrete structures are presented.


2000 ◽  
Vol 27 (5) ◽  
pp. 1088-1093 ◽  
Author(s):  
Marco Quirion ◽  
Gérard Ballivy

Advances in fiber optic sensing technology have made possible the installation of an extremely precise and reliable sensor in small structural members. Because of the high sensitivity and fast response of the sensor, low strain and dynamic strain can be measured. In this study, a Fabry-Perot strain sensor was cast in a high performance concrete cylinder, which had been submitted to simple compression and thermal tests. These results were compared with measurements obtained using external linear variable differential transformers fixed on concrete samples having the same composition as the fiber optic instrumented concrete cylinder. Comparisons were also done with results from tests on concrete cylinders instrumented with embedment vibrating wire and electrical strain gauges. In addition, thermal tests were performed on the different concrete cylinders and samples in order to compare the behaviour of the different sensors in high performance concrete submitted to temperature variations. The results show that the concrete strains measured with the Fabry-Perot sensor are in agreement with strain measurements made on concrete samples. Consequently, the presence of the embedded fiber optic sensor does not influence greatly the mechanical properties of concrete. Furthermore, for high stress levels (0.4 f 'c) and rapid stress changes (0.25 MPa/s), the fiber optic sensor measures with higher accuracy the strains of high performance concrete than the vibrating wire strain gauge.Key words: high performance concrete, sensor, vibrating wire, strain, extensometer, Fabry-Perot, fiber optic, instrumentation.


2013 ◽  
Vol 38 (4) ◽  
pp. 471 ◽  
Author(s):  
M. Taki ◽  
F. Zaidi ◽  
I. Toccafondo ◽  
T. Nannipieri ◽  
A. Signorini ◽  
...  

2009 ◽  
Vol 419-420 ◽  
pp. 1-4 ◽  
Author(s):  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Seong Kyum Kim ◽  
Seung Min Park

High-performance concrete (HPC) as a promising construction material has been widely used in infrastructures and high-rise buildings etc. However, its pretty high autogenous shrinkage (AS) especially in its early age becomes one of the key problems endangering long-time durability of HPC structures. This paper carried out the early age AS research of large scaled HPC column specimens by embedded Fiber Bragg-Grating (FBG) strain sensor. Temperature compensation for FBG strain sensor by thermocouple was also attempted in this paper, and the results were reasonable and acceptable comparing with the result compensated by FBG temperature sensor. Reinforcement influence, size effect and temperature effect on HPC AS were also analyzed respectively in this paper.


2020 ◽  
Vol 10 (4) ◽  
pp. 1335 ◽  
Author(s):  
Shuwen Deng ◽  
Xudong Shao ◽  
Banfu Yan ◽  
Yan Wang ◽  
Huihui Li

Joints are always the focus of the precast structure for accelerated bridge construction. In this paper, a girder-to-girder joint suitable for steel-ultra-high-performance concrete (UHPC) lightweight composite bridge (LWCB) is proposed. Two flexural tests were conducted to verify the effectiveness of the proposed T-shaped girder-to-girder joint. The test results indicated that: (1) The T-shaped joint has a better cracking resistance than the traditional I-shaped joint; (2) The weak interfaces of the T-shaped joint are set in the areas with relatively lower negative bending moment, and thus the cracking risk could be decreased drastically; (3) The natural curing scheme for the joint is feasible, and the reinforcement has a very large inhibitory effect on the UHPC material shrinkage; The joint interface is the weak region of the LWCB, which requires careful consideration in future designs. Based on the experimental test results, the design and calculation methods for the deflection, crack width, and ultimate flexural capacity in the negative moment region of LWCB were presented.


2018 ◽  
Vol 53 (7) ◽  
pp. 969-979 ◽  
Author(s):  
Tyler B Hudson ◽  
Nicolas Auwaijan ◽  
Fuh-Gwo Yuan

A real-time, in-process cure monitoring system employing a guided wave-based concept for carbon fiber reinforced polymer composites was developed. The system included a single piezoelectric disc that was bonded to the surface of the composite for excitation, and an embedded phase-shifted fiber Bragg grating for sensing. The phase-shifted fiber Bragg grating almost simultaneously measured both quasi-static strain and the ultrasonic guided wave-based signals throughout the cure cycle. A traditional FBG was also used as a base for evaluating the high sensitivity of the phase-shifted fiber Bragg grating sensor. Composite physical properties (degree of cure and glass transition temperature) were correlated to the amplitude and time of arrival of the guided wave-based measurements during the cure cycle. In addition, key state transitions (gelation and vitrification) were identified from the experimental data. The physical properties and state transitions were validated using cure process modeling software (e.g. RAVEN®). This system demonstrated the capability of using an embedded phase-shifted fiber Bragg grating to sense a wide bandwidth of signals during cure. The distinct advantages of a fiber optic-based system include multiplexing of multiple gratings along a single optical fiber, small size compared to piezoelectric sensors, ability to embed or surface mount, utilization in harsh environments, electrically passive operation, and electromagnetic interference (EMI) immunity. The embedded phase-shifted fiber Bragg grating fiber optic sensor can monitor the entire life-cycle of the composite structure from curing, post-cure/assembly, and in-service creating “smart structures”.


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