Construction assessment and long-term prediction of prestressed concrete bridges based on monitoring data

Abstract The long-term assessment of large civil infrastructures such as prestressed concrete bridges is a challenging task. The real time history related to the phased construction, the influence of the adopted constructive method, the characterization of the employed concrete and the environmental conditions are crucial aspects for accurate predictions based on Finite Element Models. Data from long-term monitoring systems have been used to improve the quality of those predictions, namely to validate the design assumptions, to calibrate the structural model, and to update the safety coefficients. The new bridge over the Tagus River in Portugal, the Leziria Bridge, comprehends a 1700 m long viaduct, which was erected using a movable scaffolding system. A long-term monitoring system was implemented and measurements were taken since the start of the construction. Based on these measurements, this work presents the analysis strategy adopted to compute the long-term behaviour based on a Finite Element Model. A detailed scanning of all information with relevance for the viaduct behaviour was performed. A full discussion concerning the real long-term behaviour is made, focusing the differences between the measurements and the results obtained with the numerical model, namely the trends due to shrinkage and creep and the variations due to the temperature. Finally, concerning to the viaduct lifetime, the predicted values for the measured parameters are updated, since the predictions based on the European standard rules presents significant bias to be used as reference values regarding the viaduct surveillance.

[1]  John Cairns,et al.  Model Code 2010 First Complete Draft Volume 1 , 2010 .

[2]  C. L. Roberts-Wollman,et al.  Measurements of Thermal Gradients and their Effects on Segmental Concrete Bridge , 2002 .

[3]  Mohamed Lachemi,et al.  Determination of the coefficient of thermal expansion of high performance concrete from initial setting , 2002 .

[4]  Pedro Borges,et al.  Automation robustness of scaffolding systems strengthened with organic prestressing , 2010 .

[5]  J. BotellaLlusiá,et al.  [Long-term results]. , 1983, Anales de la Real Academia Nacional de Medicina.

[6]  Dongning Li,et al.  Thermal design criteria for deep prestressed concrete girders based on data from Confederation Bridge , 2004 .

[7]  Dan M. Frangopol,et al.  Structural Health Monitoring and Reliability Estimation: Long Span Truss Bridge Application With Environmental Monitoring Data , 2008 .

[8]  Ahmet E. Aktan,et al.  Limitations in Structural Identification of Large Constructed Structures , 2007 .

[9]  Howard A. Perko.  Load Test Results , 2009 .

[10]  Ian N. Robertson,et al.  Prediction of vertical deflections for a long-span prestressed concrete bridge structure , 2005 .

[11]  Zdeněk P. Bažant,et al.  Prediction of concrete creep and shrinkage: past, present and future , 2001 .

[12]  Bernd Beirow,et al.  Theoretical and experimental free vibrations of tall industrial chimney with flexibility of soil , 2005 .

[13]  João Bento,et al.  Design and implementation of a monitoring system applied to a long-span prestressed concrete bridge , 2011 .

[14]  Yi-Qing Ni,et al.  Technology developments in structural health monitoring of large-scale bridges , 2005 .

[15]  O. Zienkiewicz.  The Finite Element Method In Engineering Science , 1971 .

[16]  Sung-Pil Chang,et al.  Necessity of the bridge health monitoring system to mitigate natural and man-made disasters , 2009 .

[17]  Rajeev Goel,et al.  Comparative Study of Various Creep and Shrinkage Prediction Models for Concrete , 2007 .

[18]  R. P. Johnson,et al.  General rules and rules for buildings , 2004 .