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.

scholarly journals CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder

Polymers ◽  
2014 ◽  
Vol 6 (2) ◽  
pp. 443-463 ◽  
Author(s):  
Roland Koller ◽  
Iwan Stoecklin ◽  
Sebastian Valet ◽  
Giovanni Terrasi
Keyword(s):  
Box Girder ◽  
Steel Box Girder ◽  
Long Term Performance ◽  
Term Performance

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.

Long-Term Performance of Concrete Suffered Infant Age Freezing

2012 ◽  
Vol 174-177 ◽  
pp. 524-529 ◽  
Author(s):  
Bao Lin Guo ◽  
Chang He Yu ◽  
Yu Han ◽  
Ju Peng Zhu
Keyword(s):  
Calcium Carbonate ◽  
Cross Section ◽  
Box Girder ◽  
Cover Concrete ◽  
Concrete Quality ◽  
Complicated Process ◽  
Long Term Performance ◽  
Term Performance ◽  
The Web

Interior water migrated towards the surface area when concrete suffered minus temperature during infant ages. Cover concrete became the worst part after the complicated process of water freezing – thawing, intermittent hydration of cementious materials and volatilization. Presentation quality, carbonization depth and rebound value in 120 d ages were observed and tested in situation. There were some calcium carbonate stains spread over the web, many swelling points and radial ice lens spread over the surface of box girder. The carbonization depth was over 10mm, and the rebound value of web concrete lower than 50, some areas’ lower than 35, variance larger than 30. Compared with other parts, the rebound value of web bottom concrete was the lowest and the variance biggest. For the same cross section, there were obviously difference of concrete quality between sunny face and shady ones, which enhanced the un-uniformity of element and made the stress distribution more complicated and uncertainty. Some effective measures must be taken to avoid the infant age frozen in order to assure the concrete quality constructed during the winter.

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.

Long-Term Performance of a Curved Box Girder Viaduct

2021 ◽  
Vol 35 (1) ◽  
pp. 04020135
Author(s):  
Yang Zhou ◽  
Carnot Nogueira ◽  
Kevin Rens ◽  
Chengyu Li
Keyword(s):  
Box Girder ◽  
Long Term Performance ◽  
Term Performance

Sliding materials – the often essential but generally weakest links in bridge bearings and expansion joints

2019 ◽  
Author(s):  
Gianni Moor ◽  
Simon Hoffmann ◽  
Danilo Della Ca'
Keyword(s):  
State Of The Art ◽  
Cycle Performance ◽  
Special Focus ◽  
Expansion Joints ◽  
Sliding Interfaces ◽  
Materials Used ◽  
Long Term Performance ◽  
Term Performance ◽  
Bridge Bearings

<p>Bridge bearings and expansion joints, being engineered components that accommodate movements and rotations, are typically the parts of a bridge that are subjected to the greatest demands although being far less robust than the main structure. As a result, they generally cannot offer a service life that approaches that of the bridge as a whole. Therefore, the durability of the bearings and expansion joints selected for use in a structure is an important factor to consider in maximizing life-cycle performance. Most bearings and expansion joints that facilitate significant superstructure movements have sliding interfaces, which provide much of the flexibility required by the main structure’s design. These sliding interfaces generally involve the use of non- ferrous materials such as PTFE, which are subjected to friction and abrasion with every movement, and are therefore the component parts that are subjected to the highest demands. Therefore, the performance of the sliding materials used in a bridge’s bearings and expansion joints has considerable influence on the structure’s long-term performance. This paper discusses this subject, with a special focus on the state-of-the-art UHMWPE alternative to the PTFE sliding material traditionally used in main sliding interfaces.</p>

Long-Term Performance of Steel-Concrete Composite Box Girder

2013 ◽  
Vol 838-841 ◽  
pp. 653-656
Author(s):  
Xiao Jie Liu ◽  
Ya Peng Jiang
Keyword(s):  
Initial Time ◽  
Time Varying ◽  
Box Girder ◽  
Stress And Deformation ◽  
Long Term Performance ◽  
Term Performance

In this paper, an analytical example was given to show the time-varying regularity of stress and deformation of composite box girder. The distribution of deflection along the span at initial time and ultimate time was calculated. It was found that the mid-span deflection increased rapidly during the initial 50 days, and became stable after 300 days. The stress of steel increased while the stress of concrete decreased and both of the variation rates gradually slowed down with time. The regularity of stress of steel and concrete with time are similar to that of the mid-span deflection.

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