scholarly journals Long-term Deflections in Balanced Cantilever Prestressed Concrete Bridges

2009 ◽  
Vol 4 (1) ◽  
pp. 22
Author(s):  
Eltayeb Hassan Onsa ◽  
Elsafi Mohamed Adam ◽  
Abdalla Khogali Ahmed ◽  
Mohamed Elmontasir Elbagir
Keyword(s):  
Prestressed Concrete ◽  
Concrete Bridges ◽  
Live Load ◽  
Prestressed Concrete Bridges ◽  
Prestressing Force ◽  
Load Tests ◽  
The Moment ◽  
Aashto Lrfd ◽  
Made In

Long-term deflections in balanced cantilever prestressed concrete bridges are reviewed. Burri and Shambat Bridges are taken as cases study to calculate long-term deflection. The two bridges were constructed at Khartoum State in the years 1972 and 1962, respectively. Due to the shortage of the basic data regarding the two bridges the AASHTO-LRFD is used to estimate and calculate the missing data in the two bridges. The Moment Area method is used to calculate the long-term deflections due to the dead load, live load and prestressing force. The calculated long-term deflections are compared with measured live load deflections obtained from load tests made by a Chinese contractor requested to evaluate the two bridges. Remarkable differences between theoretical and measured deflection at the end of cantilevers are encountered. The differences are probably due to the basic assumptions made in the formulations of deflection calculations. Some adjustments in the long-term deflection formulae are suggested to bring the calculated deflections in compatibility with measured ones.

Reliability Analysis of Prestressed Concrete Bridges in Mexico: Assessment and Live Load Factors Proposal

2021 ◽  
Author(s):  
Rolando Salgado-Estrada ◽  
Sergio A. Zamora-Castro ◽  
Agustín L. Herrera-May ◽  
Yessica A. Sánchez-Moreno ◽  
Yair S. Sánchez-Moreno
Keyword(s):  
Reliability Analysis ◽  
Prestressed Concrete ◽  
Concrete Bridges ◽  
Live Load ◽  
Prestressed Concrete Bridges ◽  
Load Factors

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.

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.

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