Experience in the Long-Term Monitoring of Bridges

At the end of the 1980’s, a series of existing bridges in Switzerland were equipped with a network of hydrostatic leveling devices, with the aim of following their longterm behavior. Some of the bridges were known to exhibit a steady increase in their deformations, while others were considered in stable condition. The paper describes the measurement system, and the choices that were initially made to ensure that it would be durable. After more than twenty years of operation, the long-term experience related to the operation of this system is presented. The mode of operation of the system is discussed. The results of the monitoring are shown for several bridges. In the mean time, several bridges have been strengthened by additional post-tensioning, one bridge was even strengthened twice. The effect of the additional prestressing and the subsequent changes on the long-term behavior are shown.

[1]  J. Marecos,et al.  The measurement of vertical displacements through water levelling method , 1978 .

[2]  M. Ladner.  Unusual Methods for Deflection Measurements , 1985 .

[3]  Olivier Burdet,et al.  AUTOMATIC MONITORING OF THE RIDDES BRIDGES USING ELECTRONIC INCLINOMETERS , 2002 .

[4]  William T. Estler,et al.  Large-Scale Metrology – An Update , 2002 .

[5]  Stephen Kyle,et al.  Large‐Scale Metrology , 2005 .

[6]  Olivier Burdet,et al.  Evaluation des systèmes existants pour le suivi à long terme des déformations des ponts , 2006 .

[7]  Olivier Burdet,et al.  Automatic Monitoring of Bridges using Electronic Inclinometers , 2000 .

[8]  Water levelling method in observation of structures , 1981 .

[9]  David H. Parker,et al.  Advances in hydrostatic leveling with the NPH6, and suggestions for further enhancements , 2005 .

[10]  I Markey,et al.  OBSERVATION A LONG TERME DE LA DEFORMATION DES PONTS , 1990 .

[11]  Ian Francis Markey.  Enseignements tirés d'observations des déformations de ponts en béton et d'analyses non-linéaires , 1994 .

[12]  Olivier Burdet,et al.  Long-Term Evaluation vs Short-Term Measurements : the Case of the Riddes Bridges , 2002 .

[13]  Olivier Burdet,et al.  ENSEIGNEMENTS TIRES D'ESSAIS DE CHARGE ET D'OBSERVATIONS A LONG TERME POUR L'EVALUATION DES PONTS EN BETON ET LE CHOIX DE LA PRECONTRAINTE , 1995 .

[14]  Olivier Burdet,et al.  Long-term deflection monitoring of prestressed concrete bridges retrofitted by external post-tensioning - examples from Switzerland , 1999 .