Load Rating a Prestressed Concrete Double T-Beam Bridge without Plans by Field Testing

2015 ◽  
Vol 2522 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Carlos V. Aguilar ◽  
David V. Jáuregui ◽  
Craig M. Newtson ◽  
Brad D. Weldon ◽  
Tamara M. Cortez
Keyword(s):  
New Mexico ◽  
Prestressed Concrete ◽  
Field Testing ◽  
Concrete Bridges ◽  
Load Rating ◽  
Load Testing ◽  
Prestressing Steel ◽  
Lack Of Information ◽  
Beam Bridge ◽  
T Beam

Bridges with no design plans are an issue in New Mexico because of the many that exist throughout the state. Conventional load rating techniques cannot be used because these bridges have limited or no design documentation. This lack of information has created uncertainties regarding the load-carrying capacity of these structures. Only a few states have formal procedures on how these particular bridges should be load rated. A project was conducted for the New Mexico Department of Transportation to develop a procedure for load rating bridges without plans, including prestressed concrete bridges. In accordance with the AASHTO Manual for Bridge Evaluation, a prestressed concrete double T-beam bridge was evaluated with advanced analyses and experimental methods (including load testing and nondestructive material evaluation techniques). A four-step load rating procedure was implemented that included estimating the prestressing steel by Magnel diagrams, verifying the estimate with a rebar scanner, testing the bridge at both diagnostic and proof loads based on strain measurements, and using the proof test results to rate the bridge. Rating factors and posting loads were determined for AASHTO and New Mexico legal loads. Because of the poor condition of the shear keys (some of which were broken), it is shown that the load distribution between beams was adversely affected and the bridge should be load posted.

scholarly journals Assessment of Mechanical Properties of Corroded Prestressing Strands

2020 ◽  
Vol 10 (12) ◽  
pp. 4055 ◽  
Author(s):  
Chi-Ho Jeon ◽  
Cuong Duy Nguyen ◽  
Chang-Su Shim
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Prestressed Concrete ◽  
Critical Issue ◽  
Concrete Bridges ◽  
Structural Behavior ◽  
Maximum Deformation ◽  
Prestressing Steel ◽  
External Tendons ◽  
Governing Factor

The corrosion of prestressing steel in prestressed concrete bridges is a critical issue for bridge maintenance. To assess structures with corroded strands, it is necessary to define the mechanical properties of the strands and their influence on the structural behavior. In this study, corroded strands were taken from external tendons in existing post-tensioned concrete bridges and tested to determine the effects of corrosion on their tensile properties. Empirical equations for the tensile strength and ductility of the corroded strands were proposed using test results. The most corroded wire governs the mechanical properties of the strand. Experiments on prestressed concrete beams with a single corroded strand were conducted to investigate their structural behavior. A reduction in the flexural strength and maximum deformation was observed in these experiments. According to the section loss of a wire in a strand and its location in a beam, the flexural capacity can be evaluated using the proposed equation. The reduced ultimate strain of the corroded strand can be the governing factor of the flexural strength.

The Disease Treatment Measures and Intensification of Reinforced Concrete T-Shaped Girder Bridges

2012 ◽  
Vol 532-533 ◽  
pp. 321-324 ◽  
Author(s):  
Ya Xun Yang ◽  
Zhi Kui Yang ◽  
Chao Qiao
Keyword(s):  
Reinforced Concrete ◽  
Detailed Analysis ◽  
Prestressed Concrete ◽  
Bridge Construction ◽  
Disease Treatment ◽  
Girder Bridges ◽  
Good Economy ◽  
Treatment Measures ◽  
Beam Bridge ◽  
T Beam

Reinforced concrete and Prestressed concrete T-beam bridge are widely used because they have the features of good economy and easy construction in bridge construction. However, with the increase in traffic and the growth of hours of operation, diseases like the increase of the deflection in this bridge,the more cracks,etc.,are being emerging gradually.According to the disease of Chun Ma Bridge while that is being used, we have made a detailed analysis,and proposed purposeful measures to deal with the disease as well as the design to reinforce the bridge,solved the problem of the safety in the bridge operation. This article have made a good in-depth discussion and analysis on the T-beam retrofitting,and it will have a guidance significance for the similar bridges in the future.

Fatigue reliability of deteriorating prestressed concrete bridges due to stress corrosion cracking

2001 ◽  
Vol 28 (4) ◽  
pp. 673-683 ◽  
Author(s):  
M A Maes ◽  
X Wei ◽  
W H Dilger
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Prestressed Concrete ◽  
Corrosion Cracking ◽  
Concrete Bridges ◽  
Concrete Bridge ◽  
Fatigue Reliability ◽  
Prestressing Steel ◽  
Prestressed Concrete Bridges ◽  
Prestressed Concrete Bridge

In this paper, an analysis framework is presented to develop a relationship between fatigue reliability in a prestressed concrete bridge and the progress of stress corrosion cracking (SCC) in prestressing steel. The fatigue limit state uses a cumulative damage model for prestressing steel wires, which is a function of both stress range and minimum stress. The SCC model takes into account varying degrees of material susceptibility, stress regimes, and environmental conditions and is structured around three stages: initiation of micro-cracking, propagation, and macro-crack instability using linear elastic fracture mechanics. The framework is an overall time-dependent analysis of the safety against fatigue of a prestressed concrete bridge. It involves a stochastic analysis of the evolution of prestressing wire corrosion as a function of time and a time-dependent probabilistic analysis of the fatigue reliability of the prestressed concrete bridge suffering a certain degree of deterioration. The uncertainties involved in the fatigue model, the SCC model, and traffic actions are considered. The updating of uncertainties is simplified by considering a limited number of classes representative of the severity of SCC exposure. The framework is applied to three deteriorating highway bridges.Key words: fatigue analysis, prestressing strands, stress corrosion cracking, reliability assessment, prestressed concrete bridges, deterioration.

Diagnostic Load Tests of a Prestressed Concrete Bridge Damaged by Overheight Vehicle Impact

2000 ◽  
Vol 1696 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Francesco M. Russo ◽  
Terry J. Wipf ◽  
F. Wayne Klaiber
Keyword(s):  
Prestressed Concrete ◽  
Load Distribution ◽  
Significant Loss ◽  
Concrete Bridges ◽  
Load Testing ◽  
Prestressed Concrete Bridges ◽  
Load Tests ◽  
Damaged Beams ◽  
Remaining Capacity ◽  
Live Load Distribution

A series of diagnostic load tests performed on two prestressed concrete bridges located in western Iowa are discussed. The bridges are dual prestressed concrete I-beam structures. In June 1996, an overheight vehicle struck the westbound structure and caused significant loss of section and cracking. As a result of the severity of the damage and because of concerns about the remaining capacity and long-term durability of the damaged beams, the Iowa Department of Transportation decided to remove the two most severely damaged beams. The diagnostic load-testing portion of the research program consisted of positioning test vehicles of known weight at predetermined locations along the deck of the damaged westbound and undamaged eastbound bridge. Single-and dual-truck tests were conducted on each bridge. Following replacement of the damaged beams in the westbound structure, additional tests were conducted. The results of these three load tests are compared to determine the effect of the localized beam damage on the overall live load distribution pattern in the bridge. The objective of this research is to determine the effects of damage on the load distribution and the remaining strength of damaged prestressed concrete bridges. Noticeable differences in response were detected in the westbound and eastbound bridges before beam replacement, with the difference essentially disappearing after the repair of the westbound bridge. The research project also involved model bridge testing, along with the repair of the beams that were removed from service and those that were intentionally damaged in the laboratory. The project is now complete.

scholarly journals Assessment of Mechanical Properties of Corroded Prestressing Strands

2020 ◽  
Author(s):  
Chi-Ho Jeon ◽  
Cuong Duy Nguyen ◽  
Chang-Su Shim
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Prestressed Concrete ◽  
Critical Issue ◽  
Concrete Bridges ◽  
Structural Behavior ◽  
Maximum Deformation ◽  
Prestressing Steel ◽  
Governing Factor ◽  
Existing Bridges

The corrosion of prestressing steel in prestressed concrete bridges is a critical issue for bridge maintenance. To assess structures with corroded strands, it is necessary to define the mechanical properties of the strands and their influence on the structural behavior. In this study, corroded strands are taken from external tendons in existing bridges and tested to define the effects of corrosion on the tensile properties of the strand. Empirical equations for the tensile strength and ductility of the corroded strand are proposed using test results. The most corroded wire governs the mechanical properties of the strand. Experiments on prestressed concrete beams with a single corroded strand are conducted to investigate the structural behavior. A reduction in the flexural strength and maximum deformation is observed from the experiment. According to the section loss of a wire in a strand and its location in a beam, the flexural capacity can be evaluated using the proposed equation. The reduced ultimate strain of the corroded strand can be the governing factor of the flexural strength.

scholarly journals DAMAGE TO CONCRETE BRIDGES DUE TO REINFORCEMENT CORROSION

Transport ◽  
2002 ◽  
Vol 17 (4) ◽  
pp. 137-142 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Prestressed Concrete ◽  
Poor Quality ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Prestressing Steel ◽  
Existing Structures ◽  
Concrete Carbonation ◽  
Prestressed Reinforcement ◽  
Segmental Bridge

Corrosion of reinforcement initiated by concrete carbonation and chloride contamination is the most common type of deterioration of concrete bridges. Based on the author's experience a number of cases is reported in which the corrosion of ordinary and prestressed reinforcement as well as the causes and consequences of deterioration observed are presented. Investigations have shown that the main reasons are: insufficient concrete cover, poor quality of concrete, and ingress of aggressive salts. The carbonation depth must be related to the histogram ofrebar cover depths and the probability of their coincidence can be predicted. The monitoring of tendon conditions in prestressed concrete precast post-tensioned segmental bridge decks shows that the voids and the water are often present in the ducts leading to the local rusting of tendons. The wires used in tendons are liable to fail in tension that was observed in some prestressed concrete bridges. Unfortunately, no reliable procedures of determining the condition of prestressing steel in existing structures are available.

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