Multiscale modelling of the long-term performance of prestressed concrete structures – Case studies on T-Girder beams

2021 ◽  
Vol 231 ◽  
pp. 111761
Author(s):  
Emanuele Canestro ◽  
Alfred Strauss ◽  
Helder Sousa
Keyword(s):  
Case Studies ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
Multiscale Modelling ◽  
Long Term Performance ◽  
Term Performance

scholarly journals Probability-Based Concrete Carbonation Prediction Using On-Site Data

2020 ◽  
Vol 10 (12) ◽  
pp. 4330
Author(s):  
Hyunjun Jung ◽  
Seok-Been Im ◽  
Yun-Kyu An
Keyword(s):  
Probabilistic Approach ◽  
Concrete Structures ◽  
Design Parameters ◽  
Degree Of Hydration ◽  
Concrete Carbonation ◽  
Remaining Service Life ◽  
Long Term Performance ◽  
Term Performance ◽  
Prediction Approach

This study proposes a probability-based carbonation prediction approach for successful monitoring of deteriorating concrete structures. Over the last several decades, a number of researchers have studied the concrete carbonation prediction to estimate the long-term performance of carbonated concrete structures. Recently, probability-based durability analyses have been introduced to precisely estimate the carbonation of concrete structures. Since the carbonation of concrete structures, however, can be affected by material compositions as well as various environmental conditions, it is still a challenge to predict concrete carbonation in the field. In this study, the Fick’s first law and a Bayes’ theorem-based carbonation prediction approach is newly proposed using on-site data, which were obtained over 19 years. In particular, the effects of design parameters such as diffusion coefficient, concentration, absorption quantity of CO2, and the degree of hydration have been thoroughly considered in this study. The proposed probabilistic approach has shown a reliable prediction of concrete carbonation and remaining service life.

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 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.

The Long-Term Performance of Nuclear Waste Forms: Natural Materials - Three Case Studies

1992 ◽  
Vol 294 ◽  
Author(s):  
Rodney C. Ewing
Keyword(s):  
Case Studies ◽  
Nuclear Waste ◽  
Experimental Results ◽  
Waste Form ◽  
Short Term ◽  
Waste Forms ◽  
Long Term Performance ◽  
Term Performance ◽  
Nuclear Waste Forms

ABSTRACTNatural materials may be used to advantage in the evaluation of the long-term performance of nuclear waste forms. Three case studies are presented: (I) radiation effects in ceramic waste forms; (II) corrosion products of U02 under oxic conditions; (III) corrosion rate of nuclear waste glasses. For each case, a natural phase which is structurally and chemically analogous to the waste form is identified and used to evaluate the long-term behavior of a nuclear waste form. Short-term experimental results are compared to the observations made of analogous natural phases. The three case studies illustrate that results may range between providing fundamental data needed for the long-term evaluation of a waste form to only providing qualitative data of limited use. Although in the most rigorous view the long-term behaviour of a phase cannot be predicted, the correspondence between short-term experimental results and observations made of natural phases provides confidence in the “predicted” behavior of the waste form. The strength of this approach rests with the degree to which a mechanistic understanding of the phenomenon is attained.

Long-term performance and life-cycle-cost benefits of cathodic protection of concrete structures using galvanic anodes

2021 ◽  
Vol 42 ◽  
pp. 102467
Author(s):  
Naveen Krishnan ◽  
Deepak K. Kamde ◽  
Zameel Doosa Veedu ◽  
Radhakrishna G. Pillai ◽  
Dhruvesh Shah ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cathodic Protection ◽  
Life Cycle Cost ◽  
Concrete Structures ◽  
Cost Benefits ◽  
Long Term Performance ◽  
Term Performance

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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