The paper presents the
findings of the monitoring of the long-term
deflections of three bridges which
were retrofitted
with external post-tensioning. The emphasis is on the effect
of the additional post-tensioning on the bridge behaviour in the years
following the retrofit. The bridges are highway
prestressed concrete box-girder
bridges built by the balanced cantilever method and retrofitted with additional
exterior post-tensioning cables for deflection control. It is shown that
external posttensioning can be a successful
retrofitting technique for bridges
with serviceability limit state problems. The reported examples also highlight
the value of long term monitoring of concrete bridges for the assessment of
bridges, and for the design of retrofitting scheme.