scholarly journals Analysis of Long-Term Prestress Loss in Prestressed Concrete (PC) Structures Using Fiber Bragg Grating (FBG) Sensor-Embedded PC Strands

2021 ◽  
Vol 11 (24) ◽  
pp. 12153
Author(s):  
Sung-Tae Kim ◽  
Young-Soo Park ◽  
Chul-Hwan Yoo ◽  
Soobong Shin ◽  
Young-Hwan Park
Keyword(s):  
Optical Fiber ◽  
Prestressed Concrete ◽  
Optical Fiber Sensor ◽  
Fiber Sensor ◽  
Prestress Loss ◽  
Fbg Sensor ◽  
Embedded Pc ◽  
Long Term Performance ◽  
Term Performance

This study aims to develop a prestressed concrete steel (PC) strand with an embedded optical Fiber Bragg Grating (FBG) sensor, which has been developed by the Korea Institute of Civil Engineering and Building Technology since 2013. This new strand is manufactured by replacing the steel core of the normal PC strand with a carbon-fiber-reinforced polymer (CFRP) rod with excellent tensile strength and durability. Because this new strand is manufactured using the pultrusion method, which is a composite material manufacturing process, with an optical fiber sensor embedded in the inner center of the CFRP Rod, it ensures full composite action as well as proper function of the sensor. In this study, a creep test for maintaining a constant load and a relaxation test for maintaining a constant displacement were performed on the proposed sensor-type PC strand. Each of the two tests was conducted for more than 1000 h, and the long-term performance verification of the sensor-type PC strand was only completed by comparing the performance with that of a normal PC strand. The test specimens were fabricated by applying an optical fiber sensor-embedded PC strand, which had undergone long-term performance verification tests, to a reinforced concrete beam. Depending on whether grout was injected in the duct, the specimens were classified into composite and non-composite specimens. A hydraulic jack was used to prestress the fabricated beam specimens, and the long-term change in the prestress force was observed for more than 1600 days using the embedded optical fiber sensor. The experimental results were compared with the analytical results to determine the long-term prestress loss obtained through finite-element analysis based on various international standards.

scholarly journals Smart Sensing of PSC Girders Using a PC Strand with a Built-in Optical Fiber Sensor

2021 ◽  
Vol 11 (1) ◽  
pp. 359
Author(s):  
Sung Tae Kim ◽  
Hyejin Yoon ◽  
Young-Hwan Park ◽  
Seung-Seop Jin ◽  
Soobong Shin ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Prestressed Concrete ◽  
Steel Wire ◽  
Optical Fiber Sensor ◽  
Fiber Reinforced Polymer ◽  
Bridge Structure ◽  
Fbg Sensor ◽  
Prestressing Force ◽  
Reinforced Polymer ◽  
Loading Tests

This paper presents a multi-functional strand capable of introducing prestressing force in prestressed concrete (PSC) girders and sensing their static and dynamic behavior as well. This innovative strand is developed by replacing the core steel wire of the strand used in PSC structures with a carbon fiber-reinforced polymer (CFRP) wire with a built-in optical Fiber Bragg Grating (FBG) sensor. A full-scale girder specimen was fabricated by applying this multi-function strand to check the possibility of tracking the change of prestressing force at each construction stage. Moreover, dynamic data could be secured during dynamic loading tests without installing accelerometers and made it possible to obtain the natural frequencies of the structure. The results verified the capability to effectively manage the prestressing force in the PSC bridge structure by applying the PC strand with a built-in optical sensor known for its outstanding practicability and durability.

scholarly journals An Optical Fiber Sensor Based on La2O2S:Eu Scintillator for Detecting Ultraviolet Radiation in Real-Time

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3754 ◽  
Author(s):  
Yongji Yan ◽  
Xu Zhang ◽  
Haopeng Li ◽  
Yu Ma ◽  
Tianci Xie ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Response Time ◽  
Electromagnetic Interference ◽  
Uv Light ◽  
Optical Fiber Sensor ◽  
Temperature Response ◽  
Superior Performance ◽  
Fiber Sensor ◽  
Uv Detectors

A novel ultraviolet (UV) optical fiber sensor (UVOFS) based on the scintillating material La2O2S:Eu has been designed, tested, and its performance compared with other scintillating materials and other conventional UV detectors. The UVOFS is based on PMMA (polymethyl methacrylate) optical fiber which includes a scintillating material. Scintillating materials provide a unique opportunity to measure UV light intensity even in the presence of strong electromagnetic interference. Five scintillating materials were compared in order to select the most appropriate one for the UVOFS. The characteristics of the sensor are reported, including a highly linear response to radiation intensity, reproducibility, temperature response, and response time (to pulsed light) based on emission from a UV source (UV fluorescence tube) centered on a wavelength of 308 nm. A direct comparison with the commercially available semiconductor-based UV sensor proves the UVOFS of this investigation shows superior performance in terms of accuracy, long-term reliability, response time and linearity.

The investigation and proposed rehabilitation of the Tsing Yi South Bridge, Hong Kong

1988 ◽  
Vol 15 (2) ◽  
pp. 190-198
Author(s):  
A. S. Beard ◽  
H. S. S. Tung
Keyword(s):  
Prestressed Concrete ◽  
Load Testing ◽  
Concrete Core ◽  
Box Girder ◽  
Expansion Joints ◽  
Radiographic Inspection ◽  
Core Extraction ◽  
Long Term Performance ◽  
Term Performance

The Tsing Yi South Bridge was constructed in the early 1970s to provide access between Tsing Yi Island and the mainland at Kwai Chung. It has a prestressed concrete box girder superstructure consisting of five independent units which are monolithic with their piers and have expansion joints at the mid-span shear hinges and the abutments. During routine maintenance it was found that the superstructure cantilevers were deflecting excessively, and consequently a thorough inspection and appraisal were commissioned. These included a complete visual inspection, concrete core extraction, radiographic inspection of prestressing tendons and a programme of load testing. The bridge was also reanalyzed to check its long-term performance. Subsequently, a rehabilitation scheme was designed to recover part of the deflection. This involved the introduction of additional prestress near the box girder's top flange. Key words: prestressed concrete, structural assessment, creep, shrinkage, radiographic inspection, rehabilitation, external prestressing.

Literature Reviews and Summary of Concrete Bridge Seamless Broaden Technology

2012 ◽  
Vol 193-194 ◽  
pp. 1290-1295 ◽  
Author(s):  
Fang Yuan Li ◽  
Zheng Yuan Xie ◽  
Xiao Shuai Guo
Keyword(s):  
Concrete Bridge ◽  
Prestress Loss ◽  
Shrinkage Temperature ◽  
Literature Reviews ◽  
Rigid Connection ◽  
Long Term Performance ◽  
Term Performance ◽  
Creep And Shrinkage ◽  
Design Construction

When the bridges broaden with seamless technology, there are differences between the existing bridge and the new bridge in design, construction and service. Because of concrete creep and shrinkage, temperature effect and prestress loss, there are stress defects in the seam, which will affect the service and safety. The current methods for the seam in foreign and domestic, such as plant steel and semi-rigid connection method are passive measures based on structure exiting state, which cannot ensure the long-term performance of the seam.

Parsing on the Processing Methods of Seamline for Concrete Bridgewith Seamless Broaden Technology

2014 ◽  
Vol 587-589 ◽  
pp. 1581-1585 ◽  
Author(s):  
Fang Yuan Li ◽  
Xiao Shuai Guo
Keyword(s):  
Driving Safety ◽  
Prestress Loss ◽  
Shrinkage Temperature ◽  
Long Term Effect ◽  
Rigid Connection ◽  
The Difference ◽  
Long Term Performance ◽  
Term Performance ◽  
Creep And Shrinkage

In view of the difference in design, construction and the usage of the old and the new bridges, there are always stress defects in seamline because of the concrete creep and shrinkage, temperature effect and prestress loss, which seriously affect the service and driving safety. The current ways in foreign and domestic, such as plant steel and semi-rigid connection method, are passive processing based on structure, can’t ensure the long-term performance. According to the three direction stress existing in the seamline, this paper decomposes the material contribution and structure influence, putting forward respectively using material and structure to overcome the adverse situation, using material to remove partial long-term effect, and through the sensitivity analysis of related parameters, to make the structure bearing the rest adverse effect, ensuring the long-term performance of seamline. The relevant conclusion can provide reference for the design and construction of the concrete bridge seamline.

Performance Evaluation of Composite Prestressed Concrete Slab Bridges

2000 ◽  
Vol 1740 (1) ◽  
pp. 12-18
Author(s):  
Robert J. Peterman ◽  
Julio A. Ramirez
Keyword(s):  
Performance Evaluation ◽  
Prestressed Concrete ◽  
Concrete Slab ◽  
Reinforcement Corrosion ◽  
Moment Connections ◽  
Rate Of Penetration ◽  
Concrete Panels ◽  
Long Term Performance ◽  
Term Performance

The results from a research project that evaluated the long-term performance of bridges constructed with composite prestressed concrete panels are summarized. The particular construction system investigated used full-span prestressed concrete panels that would be typical for bridges with spans of 12 m (40 ft) or less. A full-scale bridge specimen was constructed and subjected to 5 million cycles of service loading and 48 weeks of durability exposure cycling. This was done to assess the potential for delamination as well as the resistance to chloride-induced reinforcement corrosion. The exposure cycling greatly accelerated the rate of penetration of chlorides, producing concentrations in the deck that exceeded those from bridges that had been in service for nearly 40 years. The results from this study showed that long-term composite behavior can be achieved in these structures by applying a raked finish to the top surface of the prestressed panels. Corrosion measurements revealed the need to modify the positive-moment connections at interior piers to provide a more durable structure.

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