Refined calculation of time-dependent prestress losses in prestressed concrete girders

2020 ◽  
Vol 16 (10) ◽  
pp. 1430-1446 ◽  
Author(s):  
Mingfang Yang ◽  
Jinxin Gong ◽  
Xiaoyan Yang
Keyword(s):  
Prestressed Concrete ◽  
Time Dependent ◽  
Prestress Losses ◽  
Concrete Girders ◽  
Prestressed Concrete Girders ◽  
Refined Calculation

Time-Dependent Prestress Losses in Prestressed Concrete Girders Built of High-Performance Concrete

1997 ◽  
Vol 1594 (1) ◽  
pp. 64-72 ◽  
Author(s):  
M. Myint Lwin ◽  
Bijan Khaleghi
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Time Dependent ◽  
Step Method ◽  
Time Step ◽  
Prestress Losses ◽  
Concrete Girders ◽  
Prestressed Concrete Girders ◽  
Creep And Shrinkage

The Washington State Department of Transportation is one of several state departments of transportation involved in demonstration projects to acquire information and data on the design, fabrication, and construction of prestressed concrete bridges with high-performance concrete (HPC). Predicting the time-dependent prestress losses due to the creep and shrinkage of HPC and the relaxation of prestressing steel is difficult because of the limited experience with and data on the creep and shrinkage properties of HPC. The AASHTO load resistance factor design specification approach to estimating prestress losses is discussed, and the time-step method and the modified rate-of-creep method are introduced as ways of predicting more accurately the time-dependent prestress losses. A design example is used to compare and discuss numerically the prestress losses computed by the various methods. The modified rate-of-creep analysis method yields the lowest losses. The modified rate-of-creep method is a desirable, comprehensive, applicable, and practical method for estimating time-dependent prestress losses in composite and noncomposite prestressed concrete girders with HPC. This method is suitable for manual and electronic computation.

scholarly journals State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

2020 ◽  
Vol 10 (20) ◽  
pp. 7257
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Zheng-Kuan Lee
Keyword(s):  
Prestressed Concrete ◽  
State Of The Art ◽  
Nondestructive Method ◽  
Prestress Loss ◽  
Prestress Losses ◽  
Long Span Bridges ◽  
Concrete Girders ◽  
Long Span ◽  
Vibration Responses ◽  
Prestressed Concrete Girders

Prestressing methods were used to realize long-span bridges in the last few decades. For their predictive maintenance, devices and dynamic nondestructive procedures for identifying prestress losses were mainly developed since serviceability and safety of Prestressed Concrete (PC) girders depend on the effective state of prestressing. In fact, substantial long term prestress losses can induce excessive deflections and cracking in large span PC bridge girders. However, old unsolved problematics as well as new challenges exist since a variation in prestress force does not significantly affect the vibration responses of such PC girders. As a result, this makes uncertain the use of natural frequencies as appropriate parameters for prestress loss determinations. Thus, amongst emerging techniques, static identification based on vertical deflections has preliminary proved to be a reliable method with the goal to become a dominant approach in the near future. In fact, measured vertical deflections take accurately and instantaneously into account the changes of structural geometry of PC girders due to prestressing losses on the equilibrium conditions, in turn caused by the combined effects of tendon relaxation, concrete creep and shrinkage, and parameters of real environment as, e.g., temperature and relative humidity. Given the current state of quantitative and principled methodologies, this paper represents a state-of-the-art review of some important research works on determining prestress losses conducted worldwide. The attention is principally focused on a static nondestructive method, and a comparison with dynamic ones is elaborated. Comments and recommendations are made at proper places, while concluding remarks including future studies and field developments are mentioned at the end of the paper.

scholarly journals Time-dependent reliability analyses of prestressed concrete girders strengthened with CFRP laminates

2019 ◽  
Vol 196 ◽  
pp. 109297 ◽  
Author(s):  
D. Dias-da-Costa ◽  
L.A.C. Neves ◽  
S. Gomes ◽  
S.A. Hadigheh ◽  
P. Fernandes
Keyword(s):  
Prestressed Concrete ◽  
Time Dependent ◽  
Cfrp Laminates ◽  
Concrete Girders ◽  
Prestressed Concrete Girders

Proposed evaluation and repair procedures for precast, prestressed concrete girders with end-zone cracking

PCI Journal ◽  
2012 ◽  
Vol 57 (2) ◽  
pp. 94-119 ◽  
Author(s):  
Christie J. Hasenkamp ◽  
Sameh S. Badie ◽  
Kromel E. Hanna ◽  
Maher K. Tadros
Keyword(s):  
Prestressed Concrete ◽  
Concrete Girders ◽  
Prestressed Concrete Girders ◽  
Precast Prestressed Concrete
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