Incorporation of Stress Time Dependence into Failure Projection Modeling of Corroding Bridge Post-Tensioning Tendons

CORROSION ◽  
10.5006/3607 ◽  
2020 ◽  
Vol 76 (11) ◽  
pp. 1088-1091
Author(s):  
William H. Hartt ◽  
Teddy S. Theryo
Keyword(s):  
Time Dependence ◽  
Analytical Modeling ◽  
Initial Value ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge Structures ◽  
Post Tensioning ◽  
Wire Strand ◽  
Creep And Shrinkage

Post-tensioning (PT) has evolved to become an important technology for designing long span bridge structures. However, tendon failures resulting from wire/strand corrosion have been reported as early as 2 y post construction. In response to this, a recent study introduced and evaluated an analytical modeling approach that projects corrosion-induced wire and strand fractures and tendon failures, given statistics that characterize wire corrosion rate. This past modeling effort assumed that tensile stress in tendons was constant with time at 63% of the guaranteed ultimate tensile strength (GUTS); however, in actuality this stress decreases with time over an assumed 10,000 d (approximately 27 y) from an initial value of about 70% of GUTS to a long-term value in the range 60% to 63% of ultimate at mid-span for a simply supported beam as a consequence of long-term concrete creep and shrinkage and strand relaxation. The present study builds upon this model by incorporating this time dependence of tendon stress into the failure projection modeling. Results are discussed within the context of better understanding bridge tendon integrity issues and corrosion related failure concerns.

Fire of steel and composite beam bridges

2019 ◽  
Author(s):  
Henryk Zobel ◽  
Wojciech Karwowski ◽  
Agnieszka Golubińska ◽  
Thakaa Al-Khafaji
Keyword(s):  
Fire Resistance ◽  
Composite Beam ◽  
Structural Integrity ◽  
Bridge Structure ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge Structures ◽  
Fire Scenarios ◽  
Design Construction ◽  
Cable Stayed Bridges

<p>The problem of bridge fires is growing. Because of a bad experience in Poland, it was decided to improve fire resistance of long span bridge structures, and of cable-stayed bridges in particular. Statistics shows that fire is a real threat to this kind of structure. They also confirm that the worst results of fire are for those with an orthotropic deck rather than with a concrete one. The basic problems to solve are how to predict fire resistance of a particular bridge and how to ensure safety and structural integrity of the bridge structure. Taking into account the fact that bridge standards do not include information relating to fire protection, and fire standards do not determine rules for design, construction and maintenance of such structures, there are no regulations for this problem. Fire scenarios are devoted to buildings, but the thermo-structural behavior of bridges is different.</p>

scholarly journals Damage Evaluation of Bridge Hanger Based on Bayesian Inference: Analytical Model

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yang Ding ◽  
Jing-liang Dong ◽  
Tong-lin Yang ◽  
Zhong-ping Wang ◽  
Shuang-xi Zhou ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Evaluation Model ◽  
Bayes Theorem ◽  
Damage Evaluation ◽  
Mcmc Method ◽  
Initial Value ◽  
Long Span ◽  
Long Span Bridge ◽  
Proposed Model ◽  
Analytical Expressions

With the increase of the long-span bridge, the damage of the long-span bridge hanger has attracted more and more attention. Nowadays, the probability statistics method based on Bayes’ theorem is widely used for evaluating the damage of bridge, that is, Bayesian inference. In this study, the damage evaluation model of bridge hanger is established based on Bayesian inference. For the damage evaluation model, the analytical expressions for calculating the weights by finite mixture (FM) method are derived. In order to solve the complex analytical expressions in damage evaluation model, the Metropolis-Hastings (MH) sampling of Markov chain Monte Carlo (MCMC) method was used. Three case studies are adopted to demonstrate the effect of the initial value and the applicability of the proposed model. The result suggests that the proposed model can evaluate the damage of the bridge hanger.

scholarly journals MEASUREMENT OF DEFLECTION LINE ON BRIDGES

2013 ◽  
Vol 95 (1) ◽  
pp. 64-75
Author(s):  
Rudolf Urban ◽  
Martin Štroner
Keyword(s):  
Prestressed Concrete ◽  
Concrete Structures ◽  
Measurement Procedure ◽  
Concrete Bridges ◽  
Prediction Methods ◽  
Prestressed Concrete Bridges ◽  
Long Span ◽  
Bridge Structures

Abstract Prestressed concrete bridges are very sensitive to the increase in long-term deflections. Reliable forecasts of deflections of bridge structures during construction and durability are crucial for achieving good durability. The main results of measurements are the changes of the deflection line of the bridge structures, which places special demands on the measurement procedure. Results from measurements are very useful for the improvement of mathematical prediction methods of behaviour of long span prestressed concrete structures.

Random Seismic Response Analysis of Long-Span Bridge Structures

2012 ◽  
Vol 204-208 ◽  
pp. 2157-2161 ◽  
Author(s):  
Zhang Jun Liu ◽  
Yan Fu Xing ◽  
Yong Wan
Keyword(s):  
Seismic Response ◽  
Independent Random Variables ◽  
Response Analysis ◽  
Orthogonal Expansion ◽  
Bridge Structure ◽  
Seismic Response Analysis ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge Structures ◽  
Random Seismic Response

Based on the orthogonal expansion method of stochastic processes, seismic acceleration processes can be represented as a linear combination of deterministic functions modulated by a set of mutually independent random variables. In conjunction with the probability density evolution method, the random seismic response of bridge structures can be successfully researched. A long-span bridge structure is taken as an example. The probabilistic information of the response of a long-span bridge structure in different control under earthquake excitations is investigated. The investigation provides a new approach to the random seismic response analysis of long-span bridge structures.

scholarly journals Creep Characteristics Of Concrete Used In Long-Span Arch Bridge

2019 ◽  
Vol 14 (1) ◽  
pp. 18-36 ◽  
Author(s):  
Yongbao Wang ◽  
Renda Zhao ◽  
Yi Jia ◽  
Ping Liao
Keyword(s):  
High Speed ◽  
Concrete Structures ◽  
Mountainous Area ◽  
Concrete Creep ◽  
Arch Bridge ◽  
Analysis And Design ◽  
Model Code ◽  
Long Span ◽  
Creep And Shrinkage

The reinforced concrete arch bridge with concrete-filled steel tubular stiffened skeleton is extensively used in the mountainous area of southwest China due to their long span and high stability. Beibanjiang Bridge located in Shanghai- Kunming high-speed railway, which had a record span of 445 m, has recently been completed in 2016. However, concrete creep and shrinkage have pronounced effects on the long-term deflection and stress redistribution of this bridge. Several concrete creep and shrinkage specimens in the natural environment were made to predict the long-term behaviour of this bridge accurately. They were used to measure the concrete creep and shrinkage of the core concrete and surrounding concrete used in the arch bridge. The test results were compared to ACI209 R-92 Prediction of Creep, Shrinkage and Temperature Effects in Concrete Structures model, 1990 CEB-FIP Model Code 1990: Design Code model, fib Model Code for Concrete Structures 2010 model and Creep and Shrinkage Prediction Model for Analysis and Design of Concrete Structures-Model B3. Based on the numerical fitting method, the fib Model Code for Concrete Structures 2010 model was modified to suit the concrete creep and shrinkage experimental results. Then, the modified fib Model Code for Concrete Structures 2010 model was used to predict the timedependent behaviour of a concrete arch bridge.

Influence of Prestress Degree to Long-Term Response of the Long Span Prestressed Concrete Bridges

2012 ◽  
Vol 256-259 ◽  
pp. 1542-1547
Author(s):  
Jun Xie ◽  
Yi Shu Zhou ◽  
Xiao Hua Zheng
Keyword(s):  
Prestressed Concrete ◽  
Concrete Bridges ◽  
Deformation Control ◽  
Prestressed Concrete Bridges ◽  
Long Span ◽  
Bridge Structures ◽  
Stress And Deformation ◽  
Critical Sections ◽  
Term Response

Though the prestress degree that is selected under control of the specified stress limit is a key design parameter in design of the prestressed concrete bridges, study on long-term deformation of the long span prestressed concrete beam bridges is not popular both here and abroad. This paper reveals the time-dependent regularity of long-term stress and deformation effect to the critical sections of the long span prestressed bridges from various prestress degrees, thereby the necessity of stress and deformation control consideration during design of the long span prestressed bridge structures is verified, and the prestressing expression based on stress and deflection control for relative study and design reference is given.

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