It is of primary importance
to survey and maintain our existing bridge
structures. Several countries have
set
up today what we call a «Bridge management system» allowing them to
develop strategies for testing and assessment of their
structures. Particular
considerations are given to the deterioration progress, to the evaluation of
the remaining capacity and to service life prediction. At the same time,
traffic and bridge loadings are also increasing, so it is requested to upgrade
the bridges. These maintenance and rehabilitation programmes are an economical
need for sure, but they reflect the desire to build also better quality structures.
This paper will present through few selected examples in Vietnam, Mexico and
Romania how this upgrading and
strengthening is achieved. Some specific methods
and technologies have been developed : sometimes we replace poor quality or
defective material by better quality material, or we attach an additional
load-bearing material, or we may redistribute the loading actions through
imposed deformation of the structural system. In any case, each project is
unique and it appears that strengthening and repairing a structure is really an
art.